Neurodevelopmental liability to schizophrenia: the complex mediating role of age at onset and premorbid adjustment

Investigating factors associated with the number of rehospitalizations among patients with schizophrenia disorder using penalized count regression models

Background

Schizophrenia is a chronic, severe, and debilitating mental disorder always considered one of the recurrent psychiatric diseases. This study aimed to use penalized count regression models to determine factors associated with the number of rehospitalizations of schizophrenia disorder.

Methods

This retrospective cohort study was performed on 413 schizophrenic patients who had been referred to the Sina (Farshchian) Educational and Medical Center in Hamadan, Iran, between March 2011 and March 2019. The penalized count regression models were fitted using R.3.5.2.

Results

About 73% of the patients were male. The mean (SD) of age and the number of rehospitalizations were 36.16 (11.18) years and 1.21 (2.18), respectively. According to the results, longer duration of illness (P < 0.001), having a positive family history of psychiatric illness (P = 0.017), having at least three children (P = 0.013), unemployment, disability, and retirement (P = 0.025), residence in other Hamadan province townships (P = 0.003) and having a history of arrest/prison (P = 0.022) were significantly associated with an increase in the number of rehospitalizations.

Conclusion

To reduce the number of rehospitalizations among schizophrenic patients, it is recommended to provide special medical services for patients who do not have access to specialized medical centers and to create the necessary infrastructure for the employment of patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01648-z.

Timing of cannabis exposure relative to prodrome and psychosis onset in a community-based first episode psychosis sample

Cannabis has been implicated as both a potential cause and adverse prognostic factor in psychotic disorders. Investigating the contributory role of cannabis toward the overall burden of psychotic illnesses may represent an important step toward psychosis prevention and treatment. The current study samples consecutive admissions (N = 246) to two community based first-episode psychosis services to characterize timing of cannabis use relative to psychosis and attenuated symptom onset, differences between those with and without cannabis exposure, and the association of age at first cannabis exposure with clinical and demographic variables. Both cannabis exposure (78%) and cannabis use disorders (47%) were highly prevalent at admission. In 94% of participants, cannabis use preceded the onset of both attenuated and full-threshold psychosis symptoms by several years. Earlier age at first exposure to cannabis was associated with younger age at prodrome and psychosis onset, worse premorbid functioning, and greater severity of cannabis use disorder at admission. The timing of first exposure to cannabis may have individual prognostic as well as public health significance. Documenting the prevalence and impact of cannabis use in early psychosis samples, as well as the overall incidence of psychotic disorders, will be of vital public health significance as the United States enacts cannabis legalization and cannabis products become more widely available.

Examining which factors influence age of onset in males and females with schizophrenia

OBJECTIVE

Data from the 2010 Australian National Survey of High Impact Psychosis (SHIP) was used to examine (1) what variables influence age of onset (AOO) for males and females, and (2) whether influencing variables were different between the sexes.

METHOD

Data from 622 schizophrenia patients in the SHIP sample was used. These included early life factors, encompassing family psychiatric history, childhood development, trauma and parental loss. Factors occurring within 12 months of diagnosis were also used, including drug/alcohol abuse and premorbid work and social adjustment. Based on the recognised differences in symptom profiles and AOO between the sexes, these factors were regressed separately for males and females.

RESULTS

Stepwise linear regressions showed that a family history of psychiatric disorders was significantly associated with earlier AOO in both sexes. Other variables differed between males and females. Specifically, for females, an earlier AOO was associated with poor premorbid social adjustment and the loss of a family member in childhood. Older AOO was associated with immigrant status. For males, a younger AOO was associated with unemployment at onset, poor premorbid work adjustment, parental divorce in childhood, and lifetime cannabis use. A higher premorbid IQ was associated with an older AOO.

CONCLUSION

Familial predisposition to psychiatric illness is related to earlier AOO of schizophrenia independent of sex. Males appear to have more individual-based predictive factors while females seem to have more community/social-based influences. Future directions for research in schizophrenia are suggested.

Familial and socioeconomic contributions to premorbid functioning in psychosis: Impact on age at onset and treatment response

Background.

Premorbid adjustment (PA) abnormalities in psychotic disorders are associated with an earlier age at onset (AAO) and unfavorable clinical outcomes, including treatment resistance. Prior family studies suggest that familial liability, likely reflecting increased genetic risk, and socioeconomic status (SES) contribute to premorbid maladjustment. However, their joint effect possibly indicating gene–environment interaction has not been evaluated.

Methods.

We examined whether family history of psychosis (FHP) and parental SES may predict PA and AAO in unrelated cases with first-episode psychosis (n = 108) and schizophrenia (n = 104). Premorbid academic and social functioning domains during childhood and early adolescence were retrospectively assessed. Regression analyses were performed to investigate main effects of FHP and parental SES, as well as their interaction. The relationships between PA, AAO, and response to antipsychotic medication were also explored.

Results.

Positive FHP associated with academic PA difficulties and importantly interacted with parental SES to moderate social PA during childhood (interaction p = 0.024). Positive FHP and parental SES did not predict differences in AAO. Nevertheless, an earlier AAO was observed among cases with worse social PA in childhood (β = −0.20; p = 0.005) and early adolescence (β = −0.19; p = 0.007). Further, confirming evidence emerged for an association between deficient childhood social PA and poor treatment response (p = 0.04).

Conclusions.

Familial risk for psychosis may interact with parental socioeconomic position influencing social PA in childhood. In addition, this study supports the link between social PA deviations, early psychosis onset, and treatment resistance, which highlights premorbid social functioning as a promising clinical indicator.

Gender differences measured by the MATRICS consensus cognitive battery in chronic schizophrenia patients

Using Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), previous study showed significant gender differences for cognitive deficits in immediate and delayed memory in schizophrenia patients. However, RBANS does not include reasoning and problem solving, and social cognition. These cognitive functions can significantly affect the outcomes and daily life in patients. This study examined the gender differences of cognition using the measurement and treatment research to improve cognition in schizophrenia (MATRICS) consensus cognitive battery (MCCB), especially focusing on reasoning and problem solving, and social cognition in schizophrenia patients. The results showed that healthy controls exemplified better cognition than patients in both genders in all examined MCCB scores. Male healthy controls had better reasoning and problem solving and working memory than females, but these gender differences were not presented in schizophrenia patients. Also, male schizophrenia patients showed worse cognition than females on social cognition, processing speed, verbal learning and visual learning. Our results support that male schizophrenia patients had more cognitive impairment than females on reasoning and problem solving, social cognition, processing speed, working memory, verbal learning and visual learning.

Is an Early Age at Illness Onset in Schizophrenia Associated With Increased Genetic Susceptibility? Analysis of Data From the Nationwide Danish Twin Register

Background

Early age at illness onset has been viewed as an important liability marker for schizophrenia, which may be associated with an increased genetic vulnerability. A twin approach can be valuable, because it allows for the investigation of specific illness markers in individuals with a shared genetic background.

Methods

We linked nationwide registers to identify a cohort of twin pairs born in Denmark from 1951 to 2000 (N = 31,524 pairs), where one or both twins had a diagnosis in the schizophrenia spectrum. We defined two groups consisting of; N = 788 twin pairs (affected with schizophrenia spectrum) and a subsample of N = 448 (affected with schizophrenia). Survival analysis was applied to investigate the effect of age at illness onset.

Findings

We found that early age at illness onset compared to later onset in the first diagnosed twin can be considered a major risk factor for developing schizophrenia in the second twin. Additionally, we found that the stronger genetic component in MZ twins compared to DZ twins is manifested in the proximity of assigned diagnosis within pairs.

Discussion

Early onset schizophrenia could be linked to a more severe genetic predisposition, indicating that age might be perceived as a clinical marker for genetic vulnerability for the illness.

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Early age at schizophrenia onset in one twin increases risk of illness in the second twin 4.7 times compared to a later onset.

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A stronger genetic predisposition may be needed to affect early schizophrenia onset in females compared to males.

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Genetic factors seem to play an important role in the proximity of assigned diagnosis within twin pairs.

The main aim of this study is to examine if early age at schizophrenia onset can be viewed as a clinical marker for increased genetic vulnerability in the illness. By linking the Danish Twin Register to other nationwide health registers we obtain accurate data regarding psychiatric diagnostic outcome in a complete twin population (> 31,000 twin pairs). Our study shows how an early age at illness onset in the first diagnosed twin in a pair is a major risk factor for developing schizophrenia in the second twin, underlining the importance of genetic factors in illness vulnerability.

Altering the course of schizophrenia: progress and perspectives. Nat Rev Drug Discov. 2016;15:485-515. [PMID: 26939910 DOI: 10.1038/nrd.2016.28]

Despite a lack of recent progress in the treatment of schizophrenia, our understanding of its genetic and environmental causes has considerably improved, and their relationship to aberrant patterns of neurodevelopment has become clearer. This raises the possibility that 'disease-modifying' strategies could alter the course to - and of - this debilitating disorder, rather than simply alleviating symptoms. A promising window for course-altering intervention is around the time of the first episode of psychosis, especially in young people at risk of transition to schizophrenia. Indeed, studies performed in both individuals at risk of developing schizophrenia and rodent models for schizophrenia suggest that pre-diagnostic pharmacotherapy and psychosocial or cognitive-behavioural interventions can delay or moderate the emergence of psychosis. Of particular interest are 'hybrid' strategies that both relieve presenting symptoms and reduce the risk of transition to schizophrenia or another psychiatric disorder. This Review aims to provide a broad-based consideration of the challenges and opportunities inherent in efforts to alter the course of schizophrenia.

Predictive value of familiality, stressful life events and gender on the course of obsessive-compulsive disorder

BACKGROUND

Familiality, stressful life events (SLE) and gender significantly affect the onset of obsessive-compulsive disorder (OCD). However, their combined impact on the probability of OCD chronicity is largely unknown. With the objective of clarifying their predictive value, we tested a model of interaction effects between these influences.

METHODS

A sample of 449 patients with OCD was systematically assessed for familial loading, exposure to stressful life events, gender and course of the disease at the OCD referral unit at Bellvitge University Hospital. Multiple ordinal logistic regression was used to test interaction models.

RESULTS

Familiality presented a main negative association with chronicity (OR=0.83, CI97.5%=0.70-0.98). This association was additively moderated by both exposure to SLE before onset and gender, and showed a positive slope among female patients not exposed to SLE before onset (Familiality*SLEbo: OR=0.69, CI97.5%=0.47-1; Familiality*gender: OR=1.30, CI97.5%=0.91-1.84).

LIMITATIONS

The findings are based on cross-sectional data. Assessment of course is based on a retrospective measure, which may imply the possibility of overestimation of chronicity.

CONCLUSIONS

The predictive value of familiality on the course of OCD is only partially informative as both SLEbo and gender modify the association. When other risk factors are included in the model, familiality may predict decreased chances of chronicity. The mediation effects identified could explain the discrepancies found in previous research on this topic. Increased chances of presenting a chronic course of OCD may be found in association with familial vulnerability among female patients not exposed to SLEbo.

Sex, symptom, and premorbid social functioning associated with perceptual organization dysfunction in schizophrenia

Impairments in visual perceptual organization abilities are a repeatedly observed cognitive deficit in schizophrenia. These impairments have been found to be most prominent among patients with histories of poor premorbid social functioning, disorganized symptoms, and poor clinical outcomes. Despite the demonstration of significant sex differences for these clinical factors in schizophrenia, the extent of sex differences for visual perceptual organization in schizophrenia is unknown. Therefore, we investigated the extent to which previously known correlates (premorbid social sexual functioning and disorganized symptoms) and a novel factor (participant sex) accounted for performance on two perceptual organization tasks (contour integration and Ebbinghaus illusion) that have previously demonstrated sensitivity to schizophrenia. We also determined the relative degree to which each of these factors predicted task scores over and above the others. Schizophrenia patients (N = 109, 43 females) from different levels of care were ascertained. Female patients demonstrated higher contour integration scores, but lower performance on the context sensitivity index of the Ebbinghaus illusion, compared to males. Contour integration performance was significantly associated with poorer premorbid adolescent social sexual functioning and higher levels of disorganized symptoms, supporting past results that indicate a relationship among poor premorbid social sexual functioning, disorganized symptoms, and visual perceptual abnormalities in schizophrenia. However, analyses of Ebbinghaus illusion performance suggests there is a complex relationship among patient sex, clinical factors and perceptual abilities with relatively intact bottom-up grouping processes in females, but greater problems, compared to males with more top-down mediated context sensitivity. Therefore, sex differences may be an important consideration for future studies of visual perceptual organization in schizophrenia.

Cuprizone-induced demyelination in mice: age-related vulnerability and exploratory behavior deficit

Schizophrenia is a mental disease that mainly affects young individuals (15 to 35 years old) but its etiology remains largely undefined. Recently, accumulating evidence indicated that demyelination and/or dysfunction of oligodendrocytes is an important feature of its pathogenesis. We hypothesized that the vulnerability of young individuals to demyelination may contribute to the onset of schizophrenia. In the present study, three different age cohorts of mice, i.e. juvenile (3 weeks), young-adult (6 weeks) and middle-aged (8 months), were subjected to a 6-week diet containing 0.2% cuprizone (CPZ) to create an animal model of acute demyelination. Then, age-related vulnerability to CPZ-induced demyelination, behavioral outcomes, and myelination-related molecular biological changes were assessed. We demonstrated: (1) CPZ treatment led to more severe demyelination in juvenile and young-adult mice than in middle-aged mice in the corpus callosum, a region closely associated with the pathophysiology of schizophrenia; (2) the higher levels of demyelination in juvenile and young-adult mice were correlated with a greater reduction of myelin basic protein, more loss of CC-1-positive mature oligodendrocytes, and higher levels of astrocyte activation; and (3) CPZ treatment resulted in a more prominent exploratory behavior deficit in juvenile and young-adult mice than in middle-aged mice. Together, our data demonstrate an age-related vulnerability to demyelination with a concurrent behavioral deficit, providing supporting evidence for better understanding the susceptibility of the young to the onset of schizophrenia.

Family load estimates of schizophrenia and associated risk factors in a nation-wide population study of former child and adolescent patients up to forty years of age

OBJECTIVES

This nation-wide register-based study investigates the family load of schizophrenia (SZ) across three generations in affected families compared to control families. Furthermore the study compares the family load in case vs. control families considering the age of onset of the disorder in the cases. In addition, the study addresses the impact of certain socio-demographic risk factors, i.e. sex, region of residence, year of birth, month of birth, and maternal and paternal age at birth.

METHOD

A total of N=2020 child and adolescent psychiatric cases born between 1969 and 1985 registered in the Danish Central Psychiatric Register (DCPR) before the age of 18 developed SZ before the age of 40. N=5982 controls without any psychiatric diagnosis before age 18 were matched for age, sex, and residential region. Psychiatric diagnoses were also obtained on the first-degree relatives, i.e. parents, siblings, and offspring as a part of the Danish Three Generation Study (3GS). A family load was obtained by using various mixed regression models.

RESULTS

SZ did occur more often in case than in control families. Having a mother, father or a sibling with the disorder was proven to be a risk factor. The year of birth, the region of residence, and paternal age at birth (≥ 35) were associated with SZ. However, the family load was not dependent on age of onset of the case-proband. Furthermore, case relatives did not develop SZ earlier than control relatives.

CONCLUSIONS

These findings based on a very large and representative dataset provide further and solid evidence for the high family aggregation of SZ. The year of birth, the region of residence, and paternal age at birth play an additional role in the development of the disorder.

3-T proton magnetic spectroscopy in unmedicated first episode psychosis: a focus on creatine

Different lines of evidence suggest an abnormal cerebral energy metabolism as being critical to the pathophysiology of schizophrenia. However, it is unknown as to whether levels of creatine (Cr) would be involved in these anomalies. The study involved 33 unmedicated first episode psychosis patients and 41 healthy controls. Proton magnetic resonance spectroscopy ((1) H-MRS) was performed at 3 T using a long TE (TE/TM/TR of 240/27/3000 ms) such that within the total phosphocreatine (PCr) plus Cr signal (tCr(240)), mainly Cr was detectable. The target region was an 18 cm(3) prefrontal volume. A negative association was found between age of patients and tCr(240) levels referenced to internal water, with 20% of the variance in tCr(240) accounted for by Age. A secondary finding revealed 16% reduction of tCr(240) levels in patients, solely when comparing participants older than the median age of patients. No association existed between tCr(240) levels and clinical variables. These findings support previous data reporting abnormalities in brain creatine kinase isoenzymes involved with the maintenance of energy pools in schizophrenia. The implications of using a long TE are discussed in terms of the relative proportions of Cr and PCr within the tCr(240) signal, and of potential group differences in T(2) times.