Accuracy of register-based schizophrenia diagnoses in a genetic study

Comparison of new psychiatric diagnoses among Finnish children and adolescents before and during the COVID-19 pandemic: A nationwide register-based study

BACKGROUND

Coronavirus Disease 2019 (COVID-19) restrictions decreased the use of specialist psychiatric services for children and adolescents in spring 2020. However, little is known about the pattern once restrictions eased. We compared new psychiatric diagnoses by specialist services during pandemic and pre-pandemic periods.

METHODS AND FINDINGS

This national register study focused on all Finnish residents aged 0 to 17 years from January 2017 to September 2021 (approximately 1 million a year). The outcomes were new monthly diagnoses for psychiatric or neurodevelopmental disorders in specialist services. These were analyzed by sex, age, home location, and diagnostic groups. The numbers of new diagnoses from March 2020 were compared to predictive models based on previous years. The predicted and observed levels in March to May 2020 showed no significant differences, but the overall difference was 18.5% (95% confidence interval 12.0 to 25.9) higher than predicted in June 2020 to September 2021, with 3,821 more patients diagnosed than anticipated. During this period, the largest increases were among females (33.4%, 23.4 to 45.2), adolescents (34.4%, 25.0 to 45.3), and those living in areas with the highest COVID-19 morbidity (29.9%, 21.2 to 39.8). The largest increases by diagnostic groups were found for eating disorders (27.4%, 8.0 to 55.3), depression and anxiety (21.0%, 12.1 to 51.9), and neurodevelopmental disorders (9.6%, 3.0 to 17.0), but psychotic and bipolar disorders and conduct and oppositional disorders showed no significant differences and self-harm (-28.6, -41.5 to -8.2) and substance use disorders (-15.5, -26.4 to -0.7) decreased in this period. The main limitation is that data from specialist services do not allow to draw conclusions about those not seeking help.

CONCLUSIONS

Following the first pandemic phase, new psychiatric diagnoses in children and adolescents increased by nearly a fifth in Finnish specialist services. Possible explanations to our findings include changes in help-seeking, referrals and psychiatric problems, and delayed service access.

Specific adolescent prodromal symptoms associated with onset of psychosis in the Northern Finland Birth Cohort 1986

BACKGROUND

Several psychological symptoms in adolescence associate with later development of psychosis. However, it is unclear which symptoms specifically predict psychotic disorders rather than psychiatric disorders in general. We conducted a prospective study comparing how specific adolescent psychotic-like symptoms, predicted psychotic and non-psychotic hospital-treated psychiatric disorders in the population-based Northern Finland Birth Cohort 1986 (NFBC1986).

METHODS

At age 15-16 years, 6632 members of the NFBC1986 completed the PROD-screen questionnaire. New hospital-treated mental disorders of the NFBC1986 participants were detected between age 17 and 30 years from the Finnish Care Register for Health Care. Multiple covariates were used in the analysis.

RESULTS

During the follow-up, 1.1% of the participants developed a psychotic and 3.2% a non-psychotic psychiatric disorder. Three symptoms were specifically associated with onset of psychosis compared to non-psychotic psychiatric disorders: 'Difficulty in controlling one's speech, behaviour or facial expression while communicating' (adjusted OR 4.00; 95% CI 1.66-9.92), 'Difficulties in understanding written text or heard speech' (OR 2.25; 1.12-4.51), and 'Difficulty or uncertainty in making contact with other people' (OR 2.20; 1.03-4.67). Of these, the first one remained statistically significant after Bonferroni correction for multiple comparisons.

CONCLUSION

To our knowledge, this is the first general-population-based prospective study exploring psychiatric symptoms predicting the onset of hospital-treated first-episode psychosis in comparison to non-psychotic disorders. We found three symptoms related with difficulties in social interaction which predicted onset of psychosis. This is a novel finding and should be replicated.

Climatic exposures in childhood and the risk of schizophrenia from childhood to early adulthood

BACKGROUND

Season of birth is a risk factor of schizophrenia, and it is possible that cumulative exposure to climatic factors during childhood affects the risk of schizophrenia. We conducted a cohort study among 365,482 persons born in Finland in 1990-1995 to examine associations of 10-year cumulative exposure to global solar radiation and ambient temperature in childhood with schizophrenia.

METHODS

Data on schizophrenia diagnoses and sociodemographic factors from the Finnish population register and health care register were linked to daily meteorological data using residential information. The study population was followed from age 10 until the first schizophrenia diagnosis, death, emigration or December 31, 2017, whichever came first. Hazard ratios (HR) for the risk of schizophrenia were estimated using Cox proportional hazards model.

RESULTS

Compared to the lowest quintile of global solar radiation or ambient temperature, growing up in the second highest quintile (Q4) was associated with greater risk of schizophrenia. These hazard ratios were attenuated after adjustment for parental mental disorder, parental education, parental income, area-level socioeconomic characteristics and urbanicity (HR = 1.29, 95 % CI 1.06-1.58 for radiation; HR = 1.24, 95 % CI, 1.02-1.52 for temperature). Continuous linear terms evaluated in secondary models suggested a greater risk of schizophrenia at greater childhood exposure to global radiation and ambient temperature, but these associations did not remain in fully adjusted models.

CONCLUSIONS

We found no consistent evidence that cumulative exposure to sunlight and ambient temperature in childhood is associated with the risk of developing schizophrenia. Studies in other populations residing in different latitudes are needed.

Potential for prediction of psychosis and bipolar disorder in Child and Adolescent Mental Health Services: a longitudinal register study of all people born in Finland in 1987

Current strategies to predict psychosis identify only a small proportion of individuals at risk. Additional strategies are needed to increase capacity for pre-diction and prevention of serious mental illness, ideally during childhood and adolescence. One possible approach would be to investigate systems in which psychosis risk factors are concentrated during childhood. One notable such system is represented by Child and Adolescent Mental Health Services (CAMHS). Although psychotic disorders are uncommon in CAMHS, many risk factors for psychosis are highly prevalent in young people who enter this system. We hypothesized, therefore, that youth attending CAMHS would be a high-risk group for psychosis if followed into adulthood and, furthermore, that CAMHS systems would capture a substantial proportion of future psychosis cases. We constructed a total population cohort study of all Finns born in 1987 (N=55,875), linking together extensive register data on health care contacts from birth through age 28 years. We identified all individuals diagnosed with a psychotic or bipolar disorder by age 28 (N=1,785). The risk of psychosis/bipolar disorder by age 28 years was 1.8% for individuals who had not attended CAMHS during childhood or adolescence, whereas it was 12.8% for those with a history of any outpatient CAMHS contact (odds ratio, OR=7.9, 95% CI: 7.2-8.7). Furthermore, the risk of psychosis/bipolar disorder by age 28 years was 2.3% for individuals without a history of inpatient CAMHS admission, whereas it was 24.0% for those with a history of inpatient CAMHS admission (OR=13.3, 95% CI: 11.9-14.9), and 36.5% for those with a history of inpatient CAMHS admission in adolescence (age 13-17 years) (OR=24.2, 95% CI: 21.2-27.6). Individuals who attended CAMHS but received no mental disorder diagnosis had an equally high risk of subsequently developing a psychosis/bipolar disorder as individuals who did receive a diagnosis (OR=0.9, 99.5% CI: 0.7-1.1). Compared to other CAMHS attendees, individuals who developed psychosis or bipolar disorder were more likely to have had an initial CAMHS diagnosis of depressive or other mood disorder (OR=2.3, 99.5% CI: 1.6-3.0) and disruptive behaviour disorder (OR=1.7, 99.5% CI: 1.2-2.5). Of all psychosis/bipolar diagnoses by age 28 years, 50.2% occurred in individuals who had, at some point in childhood or adolescence, attended CAMHS, indicating that CAMHS represent not only a high-risk but also a high-capacity system for prediction of psychosis/bipolar disorder. These findings suggest an enormous, untapped potential for large-scale psychosis/bipolar disorder prediction and prevention research within existing specialist CAMHS.

Robust data-driven identification of risk factors and their interactions: A simulation and a study of parental and demographic risk factors for schizophrenia

OBJECTIVES

Few interactions between risk factors for schizophrenia have been replicated, but fitting all such interactions is difficult due to high-dimensionality. Our aims are to examine significant main and interaction effects for schizophrenia and the performance of our approach using simulated data.

METHODS

We apply the machine learning technique elastic net to a high-dimensional logistic regression model to produce a sparse set of predictors, and then assess the significance of odds ratios (OR) with Bonferroni-corrected p-values and confidence intervals (CI). We introduce a simulation model that resembles a Finnish nested case-control study of schizophrenia which uses national registers to identify cases (n = 1,468) and controls (n = 2,975). The predictors include nine sociodemographic factors and all interactions (31 predictors).

RESULTS

In the simulation, interactions with OR = 3 and prevalence = 4% were identified with <5% false positive rate and ≥80% power. None of the studied interactions were significantly associated with schizophrenia, but main effects of parental psychosis (OR = 5.2, CI 2.9-9.7; p < .001), urbanicity (1.3, 1.1-1.7; p = .001), and paternal age ≥35 (1.3, 1.004-1.6; p = .04) were significant.

CONCLUSIONS

We have provided an analytic pipeline for data-driven identification of main and interaction effects in case-control data. We identified highly replicated main effects for schizophrenia, but no interactions.

Diagnostic conversion from unipolar depression to bipolar disorder, schizophrenia, or schizoaffective disorder: A nationwide prospective 15-year register study on 43 495 inpatients

OBJECTIVE

To examine temporal patterns and predictors for diagnostic conversion from unipolar depression (UD) to bipolar disorder (BD), schizophrenia, and schizoaffective disorder (SAD).

METHODS

A prospective nationwide register-based cohort (n = 43 495) of all first psychiatric hospitalizations due to UD during 1996-2011 was followed up to 15 years. We used cumulative incidence function (CIF) analyses and the Fine-Gray subdistribution model to define the cumulative incidence of the conversions and subdistribution hazard ratios (SHRs) for predictors.

RESULTS

The overall 15-year cumulative incidence of conversion was 11.1% (95% CI 10.7-11.6): 7.4% (95% CI 7.0-7.8) for BD, 2.5% (95% CI 2.3-2.7) for schizophrenia, and 1.3% (95% CI 1.1-1.4) for SAD. The highest crude incidence rate emerged during the first year. Psychotic depression predicted higher conversion risk to BD (SHR = 2.0, 95% CI 1.5-2.7), schizophrenia (SHR = 5.3, 95% CI 3.3-8.7), and SAD (SHR = 10.6, 95% CI 4.0-28.4) than mild depression. Female sex, greater overall disturbance, and comorbid personality disorder predicted conversion to BD, whereas young age and male sex to psychotic disorders.

CONCLUSIONS

Among patients with first hospitalization due to UD, approximately one in nine converts to another major psychiatric disorder during 15 years, with the highest risk occurring within the first year. Patients with psychotic depression are particularly vulnerable for conversion to other major psychiatric disorders. Conversion to psychotic disorders occurs earlier than to BD. Males are at higher risk for progression to psychotic disorders, whereas females, patients with recurrent depressive episodes, severe disturbance of overall functioning, and personality disorder are at higher risk for converting to BD.

Hospital-treated mental and behavioral disorders and risk of Alzheimer's disease: A nationwide nested case-control study

Background:

Studies investigating psychiatric disorders as Alzheimer's disease (AD) risk factors have yielded heterogeneous findings. Differences in time windows between the exposure and outcome could be one explanation. We examined whether (1) mental and behavioral disorders in general or (2) specific mental and behavioral disorder categories increase the risk of AD and (3) how the width of the time window between the exposure and outcome affects the results.

Methods:

A nationwide nested case-control study of all Finnish clinically verified AD cases, alive in 2005 and their age, sex and region of residence matched controls (n of case-control pairs 27,948). History of hospital-treated mental and behavioral disorders was available since 1972.

Results:

Altogether 6.9% (n = 1932) of the AD cases and 6.4% (n = 1784) of controls had a history of any mental and behavioral disorder. Having any mental and behavioral disorder (adjusted OR = 1.07, 95% CI = 1.00–1.16) or depression/other mood disorder (adjusted OR = 1.17, 95% CI = 1.05–1.30) were associated with higher risk of AD with 5-year time window but not with 10-year time window (adjusted OR, 95% CI 0.99, 0.91–1.08 for any disorder and 1.08, 0.96–1.23 for depression).

Conclusions:

The associations between mental and behavioral disorders and AD were modest and dependent on the time window. Therefore, some of the disorders may represent misdiagnosed prodromal symptoms of AD, which underlines the importance of proper differential diagnostics among older persons. These findings also highlight the importance of appropriate time window in psychiatric and neuroepidemiology research.

Employment Status and Personal Income Before and After Onset of a Severe Mental Disorder: A Case-Control Study

OBJECTIVE

Individuals with severe mental disorders have an impaired ability to work and are likely to receive income transfer payments as their main source of income. However, the magnitude of this phenomenon remains unclear. Using longitudinal population cohort register data, the authors conducted a case-control study to examine the levels of employment and personal income before and after a first hospitalization for a serious mental disorder.

METHODS

All individuals (N=50,551) who had been hospitalized for schizophrenia, other nonaffective psychosis, or bipolar disorder in Finland between 1988 and 2015 were identified and matched with five randomly selected participants who were the same sex and who had the same birth year and month. Employment status and earnings, income transfer payments, and total income in euros were measured annually from 1988 to 2015.

RESULTS

Individuals with serious mental disorders had notably low levels of employment before, and especially after, the diagnosis of a severe mental disorder. Their total income was mostly constituted of transfer payments, and this was especially true for those diagnosed as having schizophrenia. More than half of all individuals with a serious mental disorder did not have any employment earnings after they received the diagnosis.

CONCLUSIONS

The current study shows how most individuals in Finland depend solely on income transfer payments after an onset of a severe mental disorder.

Mental disorders and long-term labour market outcomes: nationwide cohort study of 2 055 720 individuals

OBJECTIVE

To examine the associations between an onset of serious mental disorders before the age of 25 with subsequent employment, income and education outcomes.

METHODS

Nationwide cohort study including individuals (n = 2 055 720) living in Finland between 1988-2015, who were alive at the end of the year they turned 25. Mental disorder diagnosis between ages 15 and 25 was used as the exposure. The level of education, employment status, annual wage or self-employment earnings, and annual total income between ages 25 and 52 (measurement years 1988-2015) were used as the outcomes.

RESULTS

All serious mental disorders were associated with increased risk of not being employed and not having any secondary or higher education between ages 25 and 52. The earnings for individuals with serious mental disorders were considerably low, and the annual median total income remained rather stable between ages 25 and 52 for most of the mental disorder groups.

CONCLUSIONS

Serious mental disorders are associated with low employment rates and poor educational outcomes, leading to a substantial loss of total earnings over the life course.

Body mass index trajectories in childhood and adolescence - Risk for non-affective psychosis

BACKGROUND

Underweight in early adulthood increases risk for schizophrenia, but the effect of early childhood underweight on psychosis risk is not well known.

METHODS

We studied whether underweight or overweight in childhood and adolescence increases risk for non-affective psychosis or other psychiatric disorders in a population-based cohort study 'Cardiovascular Risk in Young Finns'. Body mass index (BMI) trajectories were recorded in the years 1980, 1983 and 1986 (in 3-18 years of age), before the first hospitalization due to a psychiatric disorder. BMI was categorized as underweight, normal weight or overweight, using the BMI classification for children and adolescents. We formed DSM-IV based diagnostic groups of non-affective psychosis (n = 69, including a schizophrenia subgroup, n = 41) and affective disorders (i.e. mood and anxiety disorders, n = 112) based on the Care Register for Health Care. Groups were compared with subjects with no psychiatric diagnoses (n = 3310). Sex, age, low birthweight and mother's mental disorders were included in the analyses.

RESULTS

Underweight, but not overweight, independently predicted later development of non-affective psychosis. The risk of psychosis was over two-fold (relative risk (RR) [95% CI] 2.31 [1.2-4.4]) and of schizophrenia nearly 2.5-fold (RR 2.44 [1.03-5.8]) after underweight in childhood/adolescence. Underweight or overweight in childhood and adolescence was not associated with mood or anxiety disorders.

CONCLUSIONS

These results support the hypothesis of non-affective psychosis as a neurodevelopmental disorder with somatic manifestations throughout childhood and adolescence.

Validation study of the early onset schizophrenia diagnosis in the Danish Psychiatric Central Research Register

The objective of this study is to assess (1) the concordance and validity of schizophrenia register diagnoses among children and adolescents (early onset schizophrenia = EOS) in the Danish Psychiatric Central Research Register (DPCRR), and (2) the validity of clinical record schizophrenia diagnoses. Psychiatric records from 200 patients with a first-time diagnosis of schizophrenia (F20.x) at age < 18 years between 1994 and 2009 in the DPCRR were rated by experienced clinicians according to ICD-10 criteria, using a predefined checklist. We retrieved 178 records, representing 19.6% of all patients diagnosed with EOS from 1994 to 2009. Mean age was 15.2 years and 56.2% were males. The register-based and clinical diagnoses matched in 158 cases (88.8%). Raters' diagnoses confirmed the DPCRR schizophrenia diagnoses in 134 cases, rendering a diagnostic validity of 75.3% of DPCRR schizophrenia, while 149 cases were confirmed as being in the schizophrenia spectrum (83.7%). When removing records with registration errors, 83.5% of cases were confirmed as schizophrenia and 91.8% as being in the schizophrenia spectrum. Interrater reliability was substantial with Cohen's kappa > 0.78-0.83 depending on classification. Compared to diagnoses made in outpatient settings, EOS diagnoses during hospitalizations were more likely to be valid and had fewer registration errors. Diagnosed in inpatient settings, EOS diagnoses are reliable and valid for register-based research. Schizophrenia diagnosed in children and adolescents in outpatient settings were found to have a high number of false-positives, both due to registration errors and diagnostic practice. Utilizing this knowledge, it is possible to reduce the number of false-positives in register-based research of EOS.

Temporal changes in the incidence of treated psychiatric and neurodevelopmental disorders during adolescence: an analysis of two national Finnish birth cohorts

BACKGROUND

Comprehensive overviews of the temporal changes in treated psychiatric and neurodevelopmental disorders during adolescence are scarce. We reviewed data from two national cohorts, 10 years apart, to establish the change in use of specialised services for psychiatric and neurodevelopmental diagnoses in Finland.

METHODS

We compared the nationwide register-based incidence of psychiatric and neurodevelopmental diagnoses between the 12th birthday and 18th birthday of adolescents born in Finland in 1987 and 1997. Adolescents who emigrated or died before their 12th birthday and those with missing covariate data were excluded, as were those who, when aged 11 years, had lived in a municipality belonging to a hospital district with obviously incomplete data reports during any follow-up years in our study. Our primary outcomes were time to incident specialised service use for any psychiatric or neurodevelopmental disorder and for 17 specific diagnostic classes. We also investigated whether adolescents who died by suicide had accessed specialised services before their deaths.

FINDINGS

The cumulative incidence of psychiatric or neurodevelopmental disorders increased from 9·8 in the 1987 cohort to 14·9 in the 1997 cohort (difference 5·2 percentage points [95% CI 4·8-5·5]) among girls, and from 6·2 in the 1987 cohort to 8·8 in the 1997 (2·6 percentage points [2·4-2·9]) among boys. The hazard ratio for the overall relative increase in neurodevelopment and psychiatric disorders in the 1997 cohort compared with the 1987 cohort was 1·6 (95% CI 1·5-1·8) among girls and 1·5 (1·4-1·6) among boys. Of the studied diagnostic classes, we noted significant (ie, p<0·001) relative increases for ten of 17 diagnoses among girls and 11 among boys. Of the adolescents who died by suicide before age 18, only five of 16 in the 1987 cohort and two of 12 in the 1997 cohort had used specialised services in the 6 months before their death.

INTERPRETATION

The large absolute rise in service use for psychiatric or neurodevelopmental disorders points to the need to deliver effective treatment to a rapidly increased patient population, whereas the relative increase in specific diagnoses should inform clinical practice. Despite increasing service use, identification of adolescents at risk of suicide remains a major public health priority.

FUNDING

Academy of Finland, Brain and Behavior Research Foundation, Finnish Medical Foundation.

Altered growth trajectory of head circumference during infancy and schizophrenia in a National Birth Cohort

Identification of abnormalities in the developmental trajectory during infancy of future schizophrenia cases offers the potential to reveal pathogenic mechanisms of this disorder. Previous studies of head circumference in pre-schizophrenia were limited to measures at birth. The use of growth acceleration of head circumference (defined as the rate of change in head circumference) provides a more informative representation of the maturational landscape of this measure compared to studies based on static head circumference measures. To date, however, no study has examined whether HC growth acceleration differs between pre-schizophrenia cases and controls. In the present study, we employed a nested case control design of a national birth cohort in Finland. Cases with schizophrenia or schizoaffective disorder (N=375) and controls (N=375) drawn from the birth cohort were matched 1:1 on date of birth (within 1month), sex, and residence in Finland at case diagnosis. Longitudinal data were obtained on head circumference from birth through age 1. Data were analyzed using a new nonparametric Bayesian inversion method which allows for a detailed understanding of growth dynamics. Adjusting for growth velocity of height and weight, and gestational age, there was significantly accelerated growth of head circumference in females with schizophrenia from birth to 2months; the findings remained significant following Bonferroni correction (p<0.0125). This is the first study to report abnormal HC growth acceleration, a more sensitive measure of somatic developmental deviation of this measure, in schizophrenia.

The quality of severe mental disorder diagnoses in a national health registry as compared to research diagnoses based on structured interview

BACKGROUND

Utilization of diagnostic information from national patient registries rests on the quality of the registered diagnoses. We aimed to investigate the agreement and consistency of diagnoses of psychotic and bipolar disorders in the Norwegian Patient Registry (NPR) compared to structured interview-based diagnoses given as part of a clinical research project.

METHODS

Diagnostic data from NPR were obtained for the period 01.01.2008-31.12.2013 for all patients who had been included in the Thematically Organized Psychosis (TOP) study between 18.10.2002 and 01.09.2014 with a Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) diagnosis of schizophrenia (n = 537), delusional disorder (n = 48), schizoaffective disorder (n = 118) or bipolar disorder (n = 408). Diagnostic agreement between the primary DSM-IV diagnosis in TOP and the International Classification of Diseases, 10th revision (ICD-10) diagnoses in NPR was evaluated using Cohen's unweighted nominal kappa (κ). Diagnostic consistency was calculated as the proportion of all registered severe mental disorder diagnoses in NPR that were equivalent to the primary diagnosis given in the TOP study.

RESULTS

The proportion of patients registered with the equivalent ICD-10 diagnosis as the primary DSM-IV diagnosis given in TOP was 84.2% for the schizophrenia group, 68.8% for the delusional disorder group, 76.3% for the schizoaffective disorder group, and 78.4% for the bipolar disorder group. Diagnostic agreement was good for schizophrenia (κ = 0.74) and bipolar disorder (κ = 0.72), fair for schizoaffective disorder (κ = 0.63), and poor for delusional disorder (κ = 0.39). Among patients with DSM-IV schizophrenia, 4.7% were diagnosed with ICD-10 bipolar disorder, and among patients with DSM-IV bipolar disorder, 2.5% were diagnosed with ICD-10 schizophrenia. Diagnostic consistency was 84.9% for schizophrenia, 59.1% for delusional disorder, 65.9% for schizoaffective disorder, and 91.0% for bipolar disorder.

CONCLUSIONS

When compared to research-based diagnoses, clinical diagnoses of schizophrenia and bipolar disorder in the NPR are accurate and consistent, with minimal diagnostic overlap between the two disorders.

Effects of childhood and adolescence physical activity patterns on psychosis risk-a general population cohort study

Schizophrenia spectrum disorders are associated with high morbidity and mortality in somatic diseases. The risk factors of this excess mortality include, e.g., obesity, dietary factors, and physical inactivity, especially after the onset of psychosis, but there are limited early developmental data on these factors in individuals who later develop psychosis. A population-based cohort study "Cardiovascular Risk of Young Finns" started in 1980 with 3596 children and adolescents from six different age groups (3, 6, 9, 12, 15, and 18 years). Cardiovascular health parameters, including questionnaire of physical activity before first hospitalization (≤18 years), were studied in 1980, 1983, and 1986. All psychiatric diagnoses of the participants were derived from the Finnish Hospital Discharge Register up to the year 2012. We identified diagnostic groups of non-affective psychosis (n = 68, including a schizophrenia subgroup, n = 41), personality disorders (n = 43), affective disorders (n = 111), and substance-related disorders (n = 49), based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Groups were compared with controls with no psychiatric diagnoses (n = 3325). Sex, age, body mass index, birth weight, non-preterm birth, and mother's mental disorders were included in the statistical model. Low physical activity in childhood and adolescence (9-18 years) independently predicted later development of non-affective psychosis. Lower physical activity index (relative risk 1.26 [1.1-1.5]), lower level of common activity during leisure time (relative risk 1.71 [1.2-2.5]), and non-participation in sports competitions (relative risk 2.58 [1.3-5.3]) were associated with a higher risk for later non-affective psychosis (expressed as increase in relative risk per physical activity unit). The findings were even stronger for schizophrenia, but no such link was observed for other diagnoses. The cause of low physical activity in premorbid/prodromal phase is likely to be multifactorial, including deviant motor and cognitive development. The results provide a rationale for including exercise and physical activity interventions as a part of psychosis prevention programs.

Can mental health diagnoses in administrative data be used for research? A systematic review of the accuracy of routinely collected diagnoses

BACKGROUND

There is increasing availability of data derived from diagnoses made routinely in mental health care, and interest in using these for research. Such data will be subject to both diagnostic (clinical) error and administrative error, and so it is necessary to evaluate its accuracy against a reference-standard. Our aim was to review studies where this had been done to guide the use of other available data.

METHODS

We searched PubMed and EMBASE for studies comparing routinely collected mental health diagnosis data to a reference standard. We produced diagnostic category-specific positive predictive values (PPV) and Cohen's kappa for each study.

RESULTS

We found 39 eligible studies. Studies were heterogeneous in design, with a wide range of outcomes. Administrative error was small compared to diagnostic error. PPV was related to base rate of the respective condition, with overall median of 76 %. Kappa results on average showed a moderate agreement between source data and reference standard for most diagnostic categories (median kappa = 0.45-0.55); anxiety disorders and schizoaffective disorder showed poorer agreement. There was no significant benefit in accuracy for diagnoses made in inpatients.

CONCLUSIONS

The current evidence partly answered our questions. There was wide variation in the quality of source data, with a risk of publication bias. For some diagnoses, especially psychotic categories, administrative data were generally predictive of true diagnosis. For others, such as anxiety disorders, the data were less satisfactory. We discuss the implications of our findings, and the need for researchers to validate routine diagnostic data.

Panic Disorder-A Malfunction of Multiple Transmitter Control Systems within the Midbrain Periaqueductal Gray Matter?

The clinical and psychopharmacological profile of panic disorder in human patients shows a remarkable similarity to the defensive behavioral response evoked in experimental animals by activation of neurons in the dorsal part of the midbrain periaqueductal gray matter (PAG). Studies of the neural circuitry within the PAG indicate that a subpopulation of GABAergic neurons in the dorsolateral sector may act as an amplifying stage that potentiates inhibitory serotonergic input to the "defense area" within the PAG. These neurons may function as a gain-control system that sets the level of excitability of efferent output neurons, which mediate the autonomic and somatomotor components of panic behavior. Dysfunctional activity within the dorsolateral PAG leading to a destabilization of this control system may be a factor underlying panic behavior and predisposes to the development of panic disorder in susceptible persons. NEUROSCIENTIST 6:48-59, 2000

Hypothyroxinemia During Gestation and Offspring Schizophrenia in a National Birth Cohort

BACKGROUND

Evidence from animal and human studies indicates that thyroid hormone deficiency during early gestation alters brain development. As schizophrenia is associated with prenatal brain insults and premorbid cognitive deficits, we tested the a priori hypothesis that serologically defined maternal thyroid deficiency during early gestation to mid-gestation is associated with schizophrenia in offspring.

METHODS

The investigation is based on the Finnish Prenatal Study of Schizophrenia, a nested case-control study that included archived maternal sera from virtually all pregnancies since 1983 (N = >1 million). We identified all offspring in the cohort with a diagnosis of schizophrenia based on the national inpatient and outpatient register and matched them on sex, date of birth, and residence in Finland at time of onset of the case to comparison subjects (1:1) from the cohort. Maternal sera of 1010 case-control pairs were assessed for free thyroxine, and sera of 948 case-control pairs were assessed for thyroid-stimulating hormone.

RESULTS

Maternal hypothyroxinemia (free thyroxine ≤10th percentile, normal thyroid-stimulating hormone) was associated with an increased odds of schizophrenia (odds ratio = 1.75, 95% confidence interval = 1.22-2.50, p = .002). When adjusted for maternal psychiatric history, province of birth, and maternal smoking during pregnancy, the association remained significant (odds ratio = 1.70, 95% confidence interval = 1.13-2.55, p = .010).

CONCLUSIONS

In a large, national birth cohort, prospectively documented hypothyroxinemia during early gestation to mid-gestation was associated with increased odds of schizophrenia in offspring. This information can inform translational studies of maternal hypothyroxinemia examining molecular and cellular deviations relevant to schizophrenia.

Maternal exposure to sexually transmitted infections and schizophrenia among offspring

Animal models and epidemiologic studies suggest that prenatal maternal infection, and sexually transmitted infection (STI) in particular, is associated with an increased risk of schizophrenia in the offspring. However, findings from prior research studies on common infections, including herpes simplex virus type 2 (HSV-2) and Chlamydia trachomatis (C. trachomatis) have been inconsistent. To investigate these associations, we conducted a case-control study nested in the population-based Finnish Prenatal Study of Schizophrenia. Using linked national registries, 963 cases with schizophrenia (ICD-10 F20) or schizoaffective disorder (ICD-10 F25), and 963 matched controls were identified from among all persons born between 1983 and 1998 in Finland. HSV-2 IgG antibody levels were quantified in archived maternal serum samples drawn during pregnancy. Mothers of 16.4% of cases versus 12.6% of controls were HSV-2 seropositive. Mean levels of maternal HSV-2 IgG were marginally higher among cases than controls (index values of 0.98 versus 0.86; p=0.06). The unadjusted odds ratio (OR) of maternal HSV-2 IgG seropositivity was 1.33 (95% confidence interval (CI)=1.03-1.72, p=0.03). Following adjustment for covariates, the relationship was attenuated (OR=1.22, CI=0.93-1.60; p=0.14). In an exploratory analysis of another STI, C. trachomatis antibodies were measured in a subsample of 207 case-control pairs drawn from the cohort. The proportions of subjects that were seropositive and the mean levels of C. trachomatis antibodies were similar for cases and controls. This study does not support a strong association of HSV-2 or C. trachomatis IgG antibodies in maternal serum during early to mid-gestation with the development of schizophrenia in the offspring.

Comparing algorithms for deriving psychosis diagnoses from longitudinal administrative clinical records

PURPOSE

Registers derived from administrative datasets are valuable tools in psychosis research, but diagnostic accuracy can be problematic. We sought to compare the relative performance of four methods for assigning a single diagnosis from longitudinal administrative clinical records when compared with reference diagnoses.

METHODS

Diagnoses recorded in inpatient and community mental health records were compared to research diagnoses of psychotic disorders obtained from semi-structured clinical interviews for 289 persons. Diagnoses were derived from administrative datasets using four algorithms; 'At least one' diagnosis, 'Last' or most recent diagnosis, 'Modal' or most frequently occurring diagnosis, and 'Hierarchy' in which a diagnostic hierarchy was applied. Agreements between algorithm-based and reference diagnoses for overall presence/absence of psychosis and for specific diagnoses of schizophrenia, schizoaffective disorder, and affective psychosis were examined using estimated prevalence rates, overall agreement, ROC analysis, and kappa statistics.

RESULTS

For the presence/absence of psychosis, the most sensitive and least specific algorithm ('At least one' diagnosis) performed best. For schizophrenia, 'Modal' and 'Last' diagnoses had greatest agreement with reference diagnosis. For affective psychosis, 'Hierarchy' diagnosis performed best. Agreement between clinical and reference diagnoses was no better than chance for diagnoses of schizoaffective disorder. Overall agreement between administrative and reference diagnoses was modest, but may have been limited by the use of participants who had been screened for likely psychosis prior to assessment.

CONCLUSION

The choice of algorithm for extracting a psychosis diagnosis from administrative datasets may have a substantial impact on the accuracy of the diagnoses derived. An 'Any diagnosis' algorithm provides a sensitive measure for the presence of any psychosis, while 'Last diagnosis' is more accurate for specific diagnosis of schizophrenia and a hierarchical diagnosis is more accurate for affective psychosis.

Elevated maternal C-reactive protein and increased risk of schizophrenia in a national birth cohort

OBJECTIVE

The objective of the present study was to investigate an association between early gestational C-reactive protein, an established inflammatory biomarker, prospectively assayed in maternal sera, and schizophrenia in a large, national birth cohort with an extensive serum biobank.

METHOD

A nested case-control design from the Finnish Prenatal Study of Schizophrenia cohort was utilized. A total of 777 schizophrenia cases (schizophrenia, N=630; schizoaffective disorder, N=147) with maternal sera available for C-reactive protein testing were identified and matched to 777 control subjects in the analysis. Maternal C-reactive protein levels were assessed using a latex immunoassay from archived maternal serum specimens.

RESULTS

Increasing maternal C-reactive protein levels, classified as a continuous variable, were significantly associated with schizophrenia in offspring (adjusted odds ratio=1.31, 95% confidence interval=1.10-1.56). This finding remained significant after adjusting for potential confounders, including maternal and parental history of psychiatric disorders, twin/singleton birth, urbanicity, province of birth, and maternal socioeconomic status.

CONCLUSIONS

This finding provides the most robust evidence to date that maternal inflammation may play a significant role in schizophrenia, with possible implications for identifying preventive strategies and pathogenic mechanisms in schizophrenia and other neurodevelopmental disorders.

Finnish Prenatal Study of Bipolar Disorders (FIPS-B): overview, design and description of the sample

BACKGROUND

Bipolar disorders (BPD) are chronic mental illnesses, the development of which involves genetic factors and environmental influences.

AIMS

The aim of this paper is to provide an overall description of the Finnish Prenatal Study of Bipolar Disorders (FIPS-B), including the study design, national registers and linkage of the registers.

METHODS

FIPS-B is a population-based prenatal epidemiological study of BPD with a nested case-control study design using several national registers. The registers used are: the Finnish Medical Birth Register (FMBR), the Finnish Hospital Discharge Register (FHDR), the Population Central Register and the Finnish Maternity Cohort (FMC), which are linked using the unique personal identity code (PIC). FIPS-B includes all children born from January 1, 1983 to December 31, 1998 and diagnosed with BPD in Finland by December 31, 2008.

RESULTS

The total number of cases included in the FIPS-B is 1887. The age at first diagnosis ranged from 4 to 25 years. Half (50.4%) of the cases utilized only outpatient services, 12.7% only inpatient services and the rest (36.9%) utilized both services. Offspring of mothers with the lowest educational level had an increased odds of BPD (OR = 1.46, 95% CI 1.13-1.88). The cumulative incidence of BPD in the population aged 25 years or younger was 11.6/10,000 in 2008.

CONCLUSIONS

FIPS-B has all the strengths of a register-based prenatal epidemiological study, along with the availability of maternal biomarkers, enabling it to examine several prenatal, perinatal and familial risk factors for BPD.

Prenatal and childhood growth, and hospitalization for alcohol use disorders in adulthood: the Helsinki birth cohort study

Background

Small birth size - an indicator of a sub-optimal prenatal environment - and variation in growth after birth have been associated with non-communicable diseases in later life. We tested whether birth size or growth in childhood associated with the risk of hospital admission for alcohol use disorders (AUDs) from early to late adulthood.

Methods

The sample comprised 6544 men and 6050 women born between 1934 and 1944 in Helsinki, Finland. Data on anthropometric measures were extracted from medical records and diagnoses of AUD from the Finnish Hospital Discharge Register and Causes of Death Register covering a 40-year period from 1969 to 2008.

Results

Altogether 171 women (2.8%) and 657 men (10.0%) were diagnosed at a hospital with AUD. After adjusting for major confounders, shorter length at birth, shorter height up to two years of age, and lower weight at two years associated with hospitalization for AUD in women. In men, slower growth in height, particularly from 2 to 7 years, and slower weight gain from 7 to 11 years as well as shorter height and lower weight at 7 and 11 years associated with a diagnosis of AUD in men.

Conclusions

Pre- and postnatal growth associates with the risk for AUD later in life differently in women than in men: the fetal period and infancy seem to be the sensitive periods for women, whereas those for men the occur from toddlerhood onwards.

A review of the reliability and validity of OPCRIT in relation to its use for the routine clinical assessment of mental health patients

The OPCRIT program is a symptom checklist with accompanying algorithms producing operationally defined diagnoses. We undertook a review of studies which had used OPCRIT and had reported statistics concerning its reliability and validity, producing summary measures from 44 studies. The first main measure of interest was inter-rater reliability where mean kappa values indicated that agreement between raters was "substantial" with a marginal improvement at the diagnostic (0.76) versus individual item (0.69) level. The second main measure of interest was convergent validity - the agreement between OPCRIT and clinical diagnoses. Most studies reported these figures as concordance rates suggesting mean agreement, unadjusted for chance, of 69%. Very few studies used the chance-adjusted kappa statistic but where this was used agreement was "fair" (0.39). Agreement between OPCRIT and other research diagnoses was "moderate" (0.60). We also considered differences between the way OPCRIT has traditionally been used in research settings and the naturalistic manner in which it will be employed in the hospital ward. This review provides a summary of the reliability and validity of OPCRIT, which will be considered during the preparation for its use in the routine characterization of mental health patients in clinical settings.

Cardiovascular morbidity, mortality and pharmacotherapy in patients with schizophrenia

BACKGROUND

Patients with schizophrenia have excess cardiovascular morbidity and mortality. Previous studies suggest that this may be partly due to inadequate somatic treatment and care, such as non-optimal use of lipid-lowering and antihypertensive pharmacotherapy, but longitudinal studies on such aetiological pathways are scarce.

METHOD

We investigated the use of lipid-lowering and antihypertensive pharmacotherapy, and the risk of hospitalization for and death from coronary heart disease and stroke among patients with schizophrenia in a birth cohort of 12 939 subjects (Helsinki Birth Cohort Study). This cohort was followed for over 30 adult years by using national databases on cardio- and cerebrovascular hospitalizations and mortality and on reimbursement entitlements and use of drugs for treatment of hypertension, dyslipidaemia, coronary heart disease and diabetes.

RESULTS

Individuals with schizophrenia had a higher risk of hospitalization for coronary heart disease [hazard ratio (HR) 1.65, 95% confidence interval (CI) 1.03-2.57], and mortality from this disease was markedly higher (HR 2.92, 95% CI 1.70-5.00), particularly among women (p=0.001 for women, p=0.008 for men). Women with schizophrenia had also marginally increased stroke mortality (p=0.06). However, patients with schizophrenia used less lipid-lowering (odds ratio 0.47, 95% CI 0.27-0.80) and antihypertensive drug treatment (HR 0.37, 95% CI 0.22-0.61).

CONCLUSIONS

In this longitudinal study, coronary heart disease morbidity was increased and coronary heart disease mortality markedly increased in patients, especially in women with schizophrenia. These patients nevertheless received less antihypertensive and lipid-lowering treatment.

Quality of the Finnish Hospital Discharge Register: a systematic review

AIMS

The Finnish Hospital Discharge Register (FHDR) is one of the oldest individual level hospital discharge registers and has been intensively used for research purposes. The aim of this study was to gather information concerning the quality of FHDR into one place in terms of a systematic review of validation studies that compare data to external information.

METHODS

Several reference databases were searched for validity articles published until January 2012. For each included study, focus of validation, register years examined, number of compared observations, external source(s) of data, summary of validation results, and conclusions concerning the validity of FHDR were extracted.

RESULTS

In total, 32 different studies comparing FHDR data to external information were identified. Most of the studies examined validity in the case of vascular disease, mental disorders or injuries. More than 95% of discharges could be identified from the register. Positive predictive value (PPV) for common diagnoses was between 75 and 99%.

CONCLUSIONS

Completeness and accuracy in the register seem to vary from satisfactory to very good in the register as long as the recognised limitations are taking into account. Poor recording of subsidiary diagnoses and secondary operations and other rarely used items are the most obvious limitations in validity, but do not compromise the value of data in FHDR in being used in studies that are not feasible to conduct otherwise.

Evidence for shared susceptibility to epilepsy and psychosis: a population-based family study

BACKGROUND

There is emerging evidence of an etiological overlap between a range of neurodevelopmental disorders, including schizophrenia and epilepsy. Here we investigate shared familial vulnerability to psychotic illness and epilepsy in a family-based study.

METHODS

The study population consisted of parents and their children born in Helsinki between 1947 and 1990. The Finnish Hospital Discharge Register was used to determine psychiatric and neurological outcomes in adulthood for all offspring. Parental history of psychosis and epilepsy was determined by linking the Hospital Discharge Register and the Finnish Population Register.

RESULTS

Our total sample comprised 9653 families and 23,404 offspring. Individuals with epilepsy had a 5.5-fold increase in the risk of having a broadly defined psychotic disorder, an almost 8.5-fold increase in the risk of having schizophrenia, and a 6.3-fold increase in the risk of having bipolar disorder. There was strong evidence of clustering of the association between epilepsy and psychosis within families. Individuals with a parental history of epilepsy had a 2-fold increase in the risk of developing psychosis, compared with individuals without a parental history of epilepsy. Individuals with a parental history of psychosis had, reciprocally, a 2.7-fold increase in the risk of having a diagnosis of generalized epilepsy, compared with individuals without a parental history of psychosis. Post hoc analyses showed that these associations were not driven by the comorbidity of epilepsy and psychosis in the parents.

CONCLUSIONS

These findings support recent evidence of overlapping etiological factors between epilepsy and schizophrenia, especially recent evidence of a genetic overlap between these disorders.

Hypertensive disorders in pregnancy and risk of severe mental disorders in the offspring in adulthood: the Helsinki Birth Cohort Study

BACKGROUND

Hypertensive disorders may affect the fetal developmental milieu and thus hint at mechanisms by which prenatal adversity associates with mental disorders in later life. We examined if hypertension without proteinuria and preeclampsia in pregnancy predict serious mental disorders in the offspring, and if sex, childhood socioeconomic status, length of gestation and parity modify these associations.

METHODS

We included 5970 women and men born after a normotensive, hypertensive or preeclamptic pregnancy defined by using mother's blood pressure and urinary protein measurements at maternity clinics and birth hospitals. Mental disorders requiring hospitalization or contributing to death were identified from the Finnish Hospital Discharge and Causes of Death Registers between years 1969 and 2004.

RESULTS

In comparison to the offspring born after normotensive pregnancies, offspring born after pregnancies complicated by hypertension without proteinuria were at 1.19-fold (CI: 1.01-1.41, P-value = 0.04) higher risk of any mental disorder and 1.44- (CI: 1.11-1.88, P-value < 0.01) and 1.39-fold (CI: 0.99-1.93, P-value = 0.05) higher risk of mood and anxiety disorder, respectively. In contrast, preeclampsia was associated, with a lower risk of any mental disorder in the male offspring (P-value = 0.02; P-value = 0.04 for interaction 'sex × normotension/preeclampsia').

CONCLUSIONS

Hypertension without proteinuria in pregnancy was associated with a higher risk of serious mental disorders in the offspring in adulthood. Preeclampsia seems to, in turn, associate with lower risk of severe mental disorders in male offspring.

Copy number variants: a new molecular frontier in clinical psychiatry

Molecular genetic research, building on genetic epidemiology, has provided the field of psychiatry with a host of exciting advances. It is now clear beyond any reasonable doubt that genetic inheritance influences liability to develop almost every major psychiatric disorder. Rapid progress in identifying genes contributing to psychiatric liability, recently accelerated by the advent of approaches such as genome-wide association studies and chromosomal microarray analysis, raises a critical question for psychiatric practice and training: how will molecular genetics alter the practice of psychiatry for front-line clinicians? The premise of the present review is that our growing knowledge regarding the roles of copy number variants in behavioral disorders will soon require revision of standards of evaluation and care for psychiatric patients.

Prenatal origins of hospitalization for personality disorders: the Helsinki birth cohort study

Although a suboptimal prenatal environment has been linked with schizophrenia and depression, possible associations with personality disorders remain unclear. The aim of this study was to examine the associations of body size at birth and length of gestation with hospitalization for personality disorders in a cohort study of 6506 men and 5857 women born in Helsinki, Finland, between 1934 and 1944. International Classification of Diseases (-8, -9, -10) diagnoses of personality disorders were extracted from the national Finnish Hospital Discharge Register since 1969. 102 men and 80 women had been hospitalized due to any personality disorder. 41 men and 30 women had dramatic personality disorders. Among men, head circumference showed an inverse J-shaped, nonlinear association with hospitalization for personality disorders. Men with a small head circumference were at increased risk. Also in men, a smaller head-to-length ratio linearly predicted personality disorders. Among women, a smaller placental area predicted increased risk of hospitalization for dramatic personality disorders. Vulnerability to personality disorders may be programmed during fetal life.

11-year follow-up of mortality in patients with schizophrenia: a population-based cohort study (FIN11 study)

BACKGROUND

The introduction of second-generation antipsychotic drugs during the 1990s is widely believed to have adversely affected mortality of patients with schizophrenia. Our aim was to establish the long-term contribution of antipsychotic drugs to mortality in such patients.

METHODS

Nationwide registers in Finland were used to compare the cause-specific mortality in 66 881 patients versus the total population (5.2 million) between 1996, and 2006, and to link these data with the use of antipsychotic drugs. We measured the all-cause mortality of patients with schizophrenia in outpatient care during current and cumulative exposure to any antipsychotic drug versus no use of these drugs, and exposure to the six most frequently used antipsychotic drugs compared with perphenazine use.

FINDINGS

Although the proportional use of second-generation antipsychotic drugs rose from 13% to 64% during follow-up, the gap in life expectancy between patients with schizophrenia and the general population did not widen between 1996 (25 years), and 2006 (22.5 years). Compared with current use of perphenazine, the highest risk for overall mortality was recorded for quetiapine (adjusted hazard ratio [HR] 1.41, 95% CI 1.09-1.82), and the lowest risk for clozapine (0.74, 0.60-0.91; p=0.0045 for the difference between clozapine vs perphenazine, and p<0.0001 for all other antipsychotic drugs). Long-term cumulative exposure (7-11 years) to any antipsychotic treatment was associated with lower mortality than was no drug use (0.81, 0.77-0.84). In patients with one or more filled prescription for an antipsychotic drug, an inverse relation between mortality and duration of cumulative use was noted (HR for trend per exposure year 0.991; 0.985-0.997).

INTERPRETATION

Long-term treatment with antipsychotic drugs is associated with lower mortality compared with no antipsychotic use. Second-generation drugs are a highly heterogeneous group, and clozapine seems to be associated with a substantially lower mortality than any other antipsychotics. Restrictions on the use of clozapine should be reassessed.

FUNDING

Annual EVO Financing (Special government subsidies from the Ministry of Health and Welfare, Finland).

Association between medication and risk of suicide, attempted suicide and death in nationwide cohort of suicidal patients with schizophrenia

PURPOSE

Mortality among schizophrenia patients is substantially higher than in the general population. The aim of this study was to investigate, in a nationwide cohort of suicidal schizophrenic individuals, how the risks of suicide, severe suicide attempts and death are associated with usage of antidepressant or antipsychotic treatment.

METHODS

The study population included all individuals in Finland who were hospitalised with a diagnosis of attempted suicide between 1 January 1997 and 31 December 2003, who also had at least one hospitalisation due to schizophrenia diagnosis (ICD-10 F20), and were at least 16 years old when the index hospitalisation began. Cox's proportional hazards modelling and Bayesian intensity estimation were used in the analysis.

RESULTS

There were 1611 patients with a mean follow-up time of 4.3 years. Current use of antipsychotics was associated with decreased mortality due to suicide (HR 0.52, 95% CI 0.34-0.81, p = 0.004), but no significant decrease in mortality was observed during current use of antidepressants (0.66, 0.41-1.08, p = 0.099), when compared to past use. In more detailed analysis when current users were compared to non-users, olanzapine, and mixed use of antipsychotics, were associated with reduced all-cause mortality, and mixed use also with reduced risk of suicide mortality. Current use of citalopram was associated with decreased all-cause and suicide mortality.

CONCLUSIONS

In a population of suicidal schizophrenic individuals antipsychotic medication, treatment was associated with lower mortality from suicide and all-causes. Antidepressive medication was associated with lower all-cause mortality when used in combination with antipsychotics.

The validity of schizophrenia diagnosis in the Finnish Hospital Discharge Register: findings from a 10-year birth cohort sample

The purpose of this study was to investigate the diagnostic validity of schizophrenia in the Finnish Hospital Discharge Register (FHDR) with a large, epidemiologically representative sample using a multidiagnostic approach (DSM-III-R, DSM-IV, ICD-10), and to find additional criteria that could be used to improve the validity of schizophrenia diagnosis in future register-based research that utilizes the FHDR. The study population consisted of all individuals (n=877) who were born in Helsinki, Finland, between 1 January 1951 and 31 December 1960, and who had had at least one diagnosis of schizophrenia, schizophreniform disorder or schizoaffective disorder in the FHDR. All their available hospital case notes were collected. The total number of subjects for whom case notes were obtained was 806. We used the OPCRIT system (version 3.4) to produce diagnoses according to ICD-10, DSM-III-R and DSM-IV criteria based on the information extracted from the hospital case notes. We examined the distribution of the DSM-III-R, DSM-IV and ICD-10 diagnoses generated by the OPCRIT and calculated the proportion of individuals who received the same diagnosis in the FHDR and in the OPCRIT assessment. The proportion of subjects who received a core schizophrenia spectrum diagnosis (schizophrenia, schizoaffective disorder or schizophreniform disorder) in both the FHDR and OPCRIT assessment varied between 75% (DSM-III-R criteria) and 78% (ICD-10 criteria). Of the subjects with a narrow schizophrenia diagnosis in the FHDR, between 74% (DSM-IV) and 78% (ICD-10) received a diagnosis of schizophrenia in the reassessment depending on the diagnostic criteria applied. Eighty per cent of those who had received a core schizophrenia spectrum FHDR diagnosis after 1982 (vs. 56% of those who had received their last schizophrenia diagnosis in 1982 or before) received a DSM-IV diagnosis of core schizophrenia spectrum disorder. Of the 58 subjects in the sample who had been given at various times diagnoses of both core schizophrenia diagnosis and bipolar I diagnosis in FHDR, 43% received a core schizophrenia spectrum diagnosis according to DSM-IV criteria. The validity of the FHDR schizophrenia diagnosis is acceptable for large-scale register studies and comparable with that of other Nordic registers. Diagnostic validity can be further improved by selecting subjects who have core schizophrenia spectrum disorder as the latest diagnosis, by omitting cases diagnosed before 1982, and by excluding cases with a register diagnoses of both a core schizophrenia spectrum and bipolar I disorder.

Case identification in psychiatric epidemiology: a review

BACKGROUND

Psychiatric epidemiologic surveys since 1980 have relied heavily on a small number of survey diagnostic instruments for case ascertainment, which encode reports of respondents to highly structured interview questions delivered by interviewers without clinical training. Many validations of these survey diagnostic instruments have been carried out.

OBJECTIVE

This paper reviews the success of the survey diagnostic instruments, for eight diagnostic categories, in validations with a psychiatrist examination as the gold standard.

METHOD

Public databases were searched for potentially relevant publications, of which more than 1000 were located. Tables show sensitivity, specificity, Kappa, sample source and size, survey instrument and validation method.

RESULTS

The number of validation studies relevant to the eight disorders ranged from 8 for schizophrenia to 29 for major depressive disorder. Reported sensitivities ranged from zero to 100%, and specificities from 22% to 100%.

CONCLUSION

Results for common mental disorders such as major depressive disorder, alcohol disorder, drug disorder, and agoraphobic disorder are better than for panic disorder, obsessive compulsive disorder, bipolar disorder, and schizophrenia. The validity of case ascertainment in psychiatric epidemiology is still in question.

The effects of genetic liability for schizophrenia and maternal smoking during pregnancy on obstetric complications

The purpose of this study was to determine whether a genetic vulnerability for schizophrenia and/or health-risk behaviors among schizophrenic pregnant women were associated with an increased incidence of obstetric complications (OCs).

METHOD

A high-risk birth cohort was formed by searching the Finnish Perinatal Register for all births from 1991-2000 with arterial cord pH values below 7.20, an indication of fetal asphyxia. This database was merged with national hospital discharge registries to determine psychiatric morbidity of the mothers and the mothers' first-degree relatives. Mothers were divided into 3 groups: women diagnosed with schizophrenia/schizoaffective disorder (n=53), mothers with a first-degree relative with schizophrenia/schizoaffective disorder (n=590) and healthy controls (n=36,895).

RESULT

Schizophrenic women had significantly more OCs than mothers with a first-degree schizophrenic relative and controls. These women had significantly increased rates of eclampsia, premature delivery, prenatal hospitalizations, and marginally significant increases in high blood pressure. Offspring of schizophrenic mothers had significantly decreased APGAR scores and birth weight and increased medical complications after birth. In contrast, women with a schizophrenic first-degree relative had no significant increases in OCs compared to controls. Schizophrenic mothers also smoked more than the other groups and smoking was found to mediate the relationship between maternal schizophrenic status and decreased birth weight among offspring.

CONCLUSIONS

Maternal schizophrenia during pregnancy leads to an increased risk of OCs, possibly due to engagement in health-risk behaviors during pregnancy, such as smoking, whereas genetic susceptibility to schizophrenia, by itself, does not appear to be related to incidence of OCs.

Utilization of routinely collected administrative data in monitoring the incidence of aging dependent hip fracture

Societies are facing challenges as the public health burden increases in tandem with population aging. Local information systems are needed that would allow a continuous monitoring of the incidence and effectiveness of treatments. This study investigates the possibilities of routinely collected administrative data as a data source for hip fracture incidence monitoring in Finland.

The study demonstrates that a straightforward use of register data results in biased estimates for the numbers of hip fractures. An interpretation of hip fractures from the population aging point of view offers an alternative perspective for hip fracture incidence calculation. This enables development of a generalizable method for probabilistic detection of starting points of hip fracture care episodes. Several risk factor and risk population extraction techniques required in register-based data analyses are also demonstrated. Finally, it is shown that empirical evidence suggests that hip fracture incidence is proportional to population level disability prevalence.

In conclusion, Finnish administrative data makes it possible to derive data for rather detailed population level risk factor stratification. Certain limitations of register-based data can be partly avoided by synthesizing data-sensitive methodological solutions during the analysis process.

Employment predictors for discharged schizophrenia patients

OBJECTIVE

To investigate predictors for competitive employment in a three-year follow-up study of discharged schizophrenia patients.

METHODS

The nationally representative sample comprised 2168 schizophrenia patients aged 15-64 years, who had been discharged from psychiatric hospitals in 1986, 1990, and 1994 in Finland. Comprehensive data were collected from psychiatric case records on the patients' sociodemographic and clinical characteristics at discharge and use of services during the follow-up period. The patients were interviewed 3 years after discharge using a structured interview schedule, which included questions on employment.

RESULTS

At follow-up, the competitive employment rate declined among the three cohorts (1989: 7.4%, 1993: 2.6% and 1997: 1.5%), whereas the rate of non-competitive employment remained at the same level (8.4%, 7.2% and 9.6%). The probability of competitive employment was higher for those who, at the time of discharge, were not on disability pension and had a current or past history of marriage, and had been discharged in the late 1980s. The probability of being competitively employed was lower for those who had no occupation at discharge and for those who had spent more time in hospital care during the three years after discharge.

CONCLUSIONS

The high unemployment rate and continuous changes in work life, which characterized Finland in the 1990s may have negatively affected the employment prospects of schizophrenia patients. Work rehabilitation should be more commonly offered, to increase their opportunities for obtaining competitive employment and for improving their quality of life.

The role of DTNBP1, NRG1, and AKT1 in the genetics of schizophrenia in Finland

Several putative schizophrenia susceptibility genes have recently been identified. Significant associations between schizophrenia and neuregulin 1 (NRG1) and dysbindin (DTNBP1) were first reported in 2002 and studies in several populations have since independently reported positive associations to these gene regions. Further, both tentative functional and genetic data have implicated the role of AKT1 in the genetic background of this disorder. However, findings have not been consistent in all populations. We investigated the allelic diversity of these three genes NRG1, DTNBP1 and AKT1 in a representative nation-wide study sample of 441 Finnish schizophrenia families consisting of 865 affected individuals, in order to assess their role in one of the largest population-based study samples. DTNBP1 and AKT1 failed to show evidence of association, whereas two SNPs in the 3' region of the NRG1 gene yielded suggestive evidence of association (p=0.012 and p=0.048) in family-based association analyses. Thus, our study does not indicate that AKT1 or DTNBP1 play a role in the etiology of schizophrenia in the Finnish population. Furthermore, results do not support a major role for NRG1, but we cannot completely exclude a minor role of this gene in the Finnish population.

Intrahepatic cholestasis of pregnancy as an indicator of liver and biliary diseases: a population-based study

Intrahepatic cholestasis of pregnancy (ICP) is a liver disorder, thought to be specific for pregnancy and to spontaneously resolve after delivery. Increased rates of gallstone formation and hepatitis C have previously been associated with ICP. However, there are no longitudinal studies to determine its significance as an indicator of subsequent liver or biliary diseases. In this retrospective cohort study with cases and controls we assessed the risk of liver and biliary diseases in 21,008 women, 10,504 with a history of ICP during the years 1972-2000 (cases) and 10,504 with a normal pregnancy (controls). Cases and controls were matched for age, time of delivery, and place of delivery. The diagnoses of liver and biliary disease were traced from the Finnish Hospital Discharge Register with an almost 100% coverage. Several liver and biliary diseases were found to have a significantly higher incidence in patients with ICP than in controls. The rate ratio for hepatitis C was 3.5 (CI 1.6-7.6; P < .001), for nonalcoholic liver cirrhosis 8.2 (CI 1.9-35.5; P < .05), for gallstones and cholecystitis 3.7 (CI 3.2-4.2; P < .001) and for nonalcoholic pancreatitis 3.2 (CI 1.7-5.7; P < .001). In conclusion, there is an association of ICP with several liver and biliary diseases. Some patients with ICP are at risk of the subsequent development of cirrhosis and other severe chronic diseases. Contrary to what has been previously thought, follow-up may need to be considered for these patients.

Affective flattening and alogia associate with the familial form of schizophrenia

Family history of schizophrenia has been associated with negative symptoms in the clinical picture. Our aim was to examine the signs and symptoms of schizophrenia in a genetically homogeneous isolate and a nationwide multiplex family sample, and to investigate the symptom dimensions and their association with the degree of familial loading for psychotic disorders and with consanguinity. For factor analysis of the Scales for the Assessment of Negative and Positive Symptoms, we included 290 patients with a DSM-IV diagnosis of schizophrenia: 63 multiplex family and 133 singleton patients from the isolate, and 94 nationwide multiplex family patients. The factor analysis yielded four factors. There was a significant difference between the multiplex and singleton patients, the former having more severe affective flattening and alogia. Further, the patients in isolate groups had fewer delusions and hallucinations compared with the whole country multiplex patients regardless of their familial loading for schizophrenia. This may be related to genetic homogeneity in the isolate. We conclude that patients with first-degree relatives with psychotic disorder have more severe negative symptoms.

Psychosis among "healthy" siblings of schizophrenia patients

BACKGROUND

Schizophrenia aggregates in families and accurate diagnoses are essential for genetic studies of schizophrenia. In this study, we investigated whether siblings of patients with schizophrenia can be identified as free of any psychotic disorder using only register information. We also analyzed the emergence of psychotic disorders among siblings of patients with schizophrenia during seven to eleven years of follow-up.

METHODS

A genetically homogenous population isolate in north-eastern Finland having 365 families with 446 patients with a diagnosis of schizophrenia was initially identified in 1991 using four nationwide registers. Between 1998 and 2002, 124 patients and 183 siblings in 110 families were contacted and interviewed using SCID-I, SCID-II and SANS. We also compared the frequency of mental disorders between siblings and a random population comparison group sample.

RESULTS

Thirty (16%) siblings received a diagnosis of psychotic disorder in the interview. 14 siblings had had psychotic symptoms already before 1991, while 16 developed psychotic symptoms during the follow-up. Over half of the siblings (n = 99, 54%) had a lifetime diagnosis of any mental disorder in the interview.

CONCLUSION

Register information cannot be used to exclude psychotic disorders among siblings of patients with schizophrenia. The high rate of emergence of new psychotic disorders among initially healthy siblings should be taken into account in genetic analysis.

Characterization of patients with schizophrenia and related psychoses: evaluation of different diagnostic procedures

BACKGROUND

We aimed at estimating the value of structured interviews, medical records and clinical diagnoses for assessing lifetime diagnosis of patients with schizophrenia. In addition, the validity of the Operational Criteria Checklist (OPCRIT) system was analysed.

SAMPLING AND METHODS

Swedish patients (n = 73), diagnosed with schizophrenia and related disorders by their treating physician, were scrutinized. Independent research diagnoses according to the Diagnostic and Statistical Manual, ed. 3, revised (DSM-III-R) were obtained by (1) a structured interview; (2) the OPCRIT algorithm, based on record analysis only; (3) the OPCRIT algorithm, based on record and interview analysis, or (4) a separate traditional research diagnosis based on both record and interview analysis. In addition, clinical International Classification of Diseases (ICD) diagnoses, given by the treating physician, were obtained from the case notes. Concordance rates for the different psychosis diagnoses were calculated.

RESULTS

Diagnoses based on interviews only showed poor to fair agreement with the other research diagnoses, but patients diagnosed with schizophrenia or schizophrenic psychoses (i.e. schizophrenia, schizophreniform or schizoaffective disorder) at the interview almost always also obtained a corresponding research diagnosis based on record or combined sources. Diagnoses based on records only showed a good to excellent agreement with diagnoses based on records and interviews. Clinical ICD diagnoses generally displayed poor agreement with the research diagnoses, but 94% of patients ever given a clinical ICD diagnosis of schizophrenic psychosis received a corresponding traditional research diagnosis. OPCRIT diagnoses and independently assigned research diagnoses, based on the same information, displayed excellent concordance.

CONCLUSIONS

Structured interviews performed with Swedish long-term-treated psychosis patients during non-hospitalization are a poor source for the evaluation of psychosis diagnoses, but a good screening instrument for the detection of DSM-III-R schizophrenia. In the investigated population, medical records are a valuable source for diagnostic assessment of psychoses and may serve as a stand-alone procedure in this patient category. Swedish clinical ICD diagnoses have a high positive predictive power identifying DSM-III-R diagnoses of schizophrenic psychoses, indicating validity of register-based research focusing on these diagnoses. The OPCRIT system is a valid tool for assessing DSM-III-R psychosis diagnoses. It should be emphasized that the present conclusions are based on the investigated Swedish psychosis population and cannot be generalized to populations composed of other patient groups or sampled in other settings, with other traditions regarding the use and availability of medical records.

Administrative registers in psychiatric research: a systematic review of validity studies

OBJECTIVE

To conduct a systematic review of studies investigating the validity of administrative registers for use in psychiatric research.

METHOD

Studies were identified using MEDLINE (1966-2004) and EMBASE (1980-2004) databases using keywords 'validity' or 'reliability' combined with 'register' or 'database$'. Studies reviewed by two raters blind to each other and quality assessed using a data extraction form devised by the authors. A narrative description of the findings is presented.

RESULTS

Fourteen studies were identified, seven of which concerned Scandinavian registers. Ten studies were solely concerned with diagnostic validity and the most common single diagnosis studied was schizophrenia (five studies). Methods used and study quality varied widely.

CONCLUSION

Given the importance of the area, relatively little high-quality work exists into systematically measuring the diagnostic data validity of registers for research purposes.

Prevalence and diagnosis of schizophrenia based on register, case record and interview data in an isolated Finnish birth cohort born 1940-1969

INTRODUCTION

Schizophrenia occurs worldwide but the prevalence varies markedly. In Finland, schizophrenia is most prevalent in the northeastern region. Our aims were to reassess the register-, case record- and interview-based lifetime prevalence in a genetically homogeneous birth cohort from an isolate population with earlier reported high prevalence of schizophrenia and a chromosome linkage to chromosome 1q.

METHODS

We identified all patients with a diagnosis of schizophrenia [International Classification of Diseases (ICD)-8, ICD-9 or ICD-10 codes], born 1940-1969 in the isolate (n=282) and alive (n=237) in 1998 using the Hospital Discharge, Disability Pension and Free Medicine Registers. The corresponding birth cohort of 14,817 persons and 12,368 alive in 1998 was identified from the National Population Register. We validated 69% of the register diagnosis by making DSM-IV consensus diagnoses, and interviewed 131 (55%) of the 237 patients with SCID-I and SCID-II.

RESULTS

The register-based lifetime prevalence was 1.5% for schizophrenia and 1.9% for schizophrenia spectrum psychotic disorders: in birth cohorts born 1945 to 1959, the latter prevalence was especially high (2.4%). Of those with a register diagnosis of schizophrenia spectrum psychotic disorder, 69% or 63% also received a record-based consensus diagnosis or SCID interview diagnosis of schizophrenia, and the prevalence was 0.9-1.3 and 0.7-1.2%, respectively, when we reassessed most of the register-based cases. The cumulative incidence of schizophrenia spectrum psychotic disorders in the total birth cohort was 1.9%.

CONCLUSION

In this isolate, the register, DSM-IV consensus and SCID interview-based lifetime prevalence of schizophrenia was internationally high. For genetic research work, the register diagnosis should be reassessed using either structured interview or the best estimate consensus diagnosis.

Evaluation of diagnostic procedures in Swedish patients with schizophrenia and related psychoses

We aimed to estimate the value of structured interviews, medical records and Swedish register diagnoses for assessing lifetime diagnosis of patients with schizophrenia. Psychiatric records and diagnostic interviews of 143 Swedish patients diagnosed by their treating physician with schizophrenia and related disorders were scrutinized. Based on record analysis only, or a combined record and interview analysis, DSM-IV diagnoses were obtained by the OPCRIT algorithm. Independent of the OPCRIT algorithm, a standard research DSM-IV diagnosis, based on both record and interview analysis, was given by the research psychiatrist. Concordance rates for the different psychosis diagnoses were calculated. DSM-IV diagnoses based on records only, showed a good to excellent agreement with diagnoses based on records and interviews. Swedish register diagnoses displayed generally poor agreement with the research diagnoses. Nevertheless, 94% of subjects sometimes registered with a diagnosis of schizophrenic psychoses (i.e. schizophrenia, schizoaffective psychosis or schizophreniform disorder) displayed a standard research DSM-IV diagnosis of these disorders. For patients in long-term treatment for schizophrenia in Sweden, psychiatric record reviews should be optimal, cost effective and sufficient for assessment of lifetime research diagnoses of schizophrenia. For these patients a research interview adds little new information. The results further indicate that a Swedish register diagnosis of schizophrenic psychoses has a high positive predictive power to a standard research DSM-IV diagnosis of the disorders. It is concluded that for future Swedish large-scale genetic studies focusing on a broad definition of schizophrenia, it would be sufficient to rely on the Swedish register diagnoses of schizophrenic psychosis.

Violent victimization in schizophrenia

BACKGROUND

We investigated the 3-year prevalence, and the sociodemographic and clinical correlates of violent victimization in a large and unselected nationwide sample of deinstitutionalized patients with schizophrenia.

METHODS

The sample comprised 670 schizophrenic patients aged 15-64 years, who had been discharged from psychiatric hospitals in Finland in 1994. Comprehensive data were collected from psychiatric case records on the patients' sociodemographic factors and psychiatric history, as well as the patients' overall level of functioning. The patients were interviewed 3 years after discharge by each district's psychiatric professionals using a structured interview schedule specifically designed for the purposes of the present study project.

RESULTS

The prevalence of self-reported violent victimization during the 3-year follow-up was 5.6%. In the multivariate analysis, a poor financial situation, alcohol abuse and being a perpetrator of a violent or some other crime were associated with violent victimization.

CONCLUSIONS

The prevalence of violent victimization among schizophrenic patients in Finland was markedly lower than that reported on patients in the United States or Great Britain, but correlates were similar. Patients with a poor financial situation and a history of alcohol misuse, as well as of violent behaviour, seem to have an increased risk for violent victimization, and constitute a vulnerable subgroup in this respect. This subgroup of deinstitutionalized patients with schizophrenia may need additional care and protection from the danger posed to them from other members of the society.

Clinical phenotype of schizophrenia in a Finnish isolate

We identified all cases in Finland (population of 5 million) with a diagnosis of schizophrenia born between 1940 and 1969, using four national computerised registers with high reliability. A sample of 397 families was identified in a genetically homogeneous internal isolate (population of 18,000) in northeastern Finland with high prevalence for schizophrenia and an LOD score of 3.8 in chromosome 1. Our aim was to examine with Operational Criteria Checklist for Psychotic Illness (OCCPI) factor analysis the psychotic and affective signs and symptoms of schizophrenia in this genetically homogeneous population, and compare them with findings from individuals with schizophrenia from multiplex families from the whole country. After collecting all original case notes, we made DSM-IV consensus diagnoses and completed OCCPI ratings on a lifetime basis. For the factor analysis, we accepted 190 patients with a diagnosis of schizophrenia. In addition, 466 schizophrenia patients from 147 multiplex families from the whole country were included in the analysis. The OCCPI factor analysis resulted in four factors: "delusions and hallucinations" and "negative" factors, plus two affective ("manic" and "depressive") factors. We compared the pattern of symptoms among three patient groups: isolate patients who were the only affected individuals in their family, isolate patients who had affected family members, and patients from the whole country with affected family members. We found no clear differences among these groups. However, there were significant differences in the frequency of individual OCCPI items between the study groups. Findings in this schizophrenia OCCPI phenotype study suggest that the clinical picture of schizophrenia in a genetically isolated and homogeneous population closely resembles our nationwide findings in Finland.

Schizophrenic patients in different treatment settings during the era of deinstitutionalization: three-year follow-up of three discharge cohorts in Finland

OBJECTIVE

We investigated differences in psychosocial and clinical characteristics, as well as the use of services, of schizophrenic patients in different treatment settings three years after their discharge from a psychiatric hospital. Furthermore, we examined secular changes in these phenomena during the era of rapid deinstitutionalization in Finland.

METHOD

Three nationally representative samples comprised 3257 schizophrenic patients who had been discharged in 1986, 1990 and 1994. The patients were interviewed three years after discharge by each district's psychiatric professionals using a structured interview schedule specifically designed for the purposes of the present study. Psychosocial functioning was assessed on the Global Assessment Scale and on a modified version of the Medical Research Council Practices Profile.

RESULTS

In the 1990s, more patients with a poor clinical and psychosocial state were transferred from hospital to alternative outpatient facilities, such as sheltered workshops or supported residences. In successive cohorts, the proportion of patients who had dropped out of treatment decreased and the psychiatric and somatic state of the drop-outs improved.

CONCLUSION

In general, the psychiatric treatment system has worked well for most deinstitutionalized patients. In the future, however, it is important that the quality of care and adequate resources in the alternative outpatient facilities are ensured.

A genomewide screen for schizophrenia genes in an isolated Finnish subpopulation, suggesting multiple susceptibility loci

Schizophrenia is a severe mental disorder affecting approximately 1% of the world's population. Here, we report the results from a three-stage genomewide screen performed in a study sample from an internal isolate of Finland. An effort was made to identify genes predisposing for schizophrenia that are potentially enriched in this isolate, which has an exceptionally high lifetime risk for this trait. Ancestors of the local families with schizophrenia were traced back to the foundation of the population in the 17th century. This genealogical information was used as the basis for the study strategy, which involved screening for alleles shared among affected individuals originating from common ancestors. We found four chromosomal regions with markers revealing pairwise LOD scores>1.0: 1q32.2-q41 (Z(max)=3.82, dominant affecteds-only model), 4q31 (Z(max)=2. 74, dominant 90%-penetrance model), 9q21 (Z(max)=1.95, dominant 90%-penetrance model), and Xp11.4-p11.3 (Z(max)=2.01, recessive 90%-penetrance model). This finding suggests that there are several putative loci predisposing to schizophrenia, even in this isolate.