Life events and depressiveness - the effect of adjustment for psychosocial factors, somatic health and genetic liability

The Co-Twin Control Design: Implementation and Methodological Considerations

Establishing causal relationships in observational studies is an important step in research and policy decision making. The association between an exposure and an outcome can be confounded by multiple factors, often making it hard to draw causal conclusions. The co-twin control design (CTCD) is a powerful approach that allows for the investigation of causal effects while controlling for genetic and shared environmental confounding factors. This article introduces the CTCD and offers an overview of analysis methods for binary and continuous outcome and exposure variables. Tools for data simulation are provided, along with practical guidance and accompanying scripts for implementing the CTCD in R, SPSS, and Stata. While the CTCD offers valuable insights into causal inference, it depends on several assumptions that are important when interpreting CTCD results. By presenting a broad overview of the CTCD, this article aims to equip researchers with actionable recommendations and a comprehensive understanding of the design's strengths and limitations.

Gendered Impact of Caregiving Responsibilities on Tenure Track Faculty Parents’ Professional Lives

Navigating a career while raising a family can be challenging, especially for women in academia. In this study, we examine the ways in which professional life interruptions due to child caregiving (e.g., opportunities not offered, professional travel curtailed) affect pre- and post-tenure faculty members’ career satisfaction and retention. We also examine whether sharing caregiving responsibilities with a partner affected faculty members’ (particularly women’s) career outcomes. In a sample of 753 tenure track faculty parents employed at a large research-intensive university, results showed that as the number of professional life interruptions due to caregiving increased, faculty members experienced less career satisfaction and greater desire to leave their job. Pre-tenure women’s, but not pre-tenure men’s, career satisfaction and intention to stay were negatively affected when they experienced at least one professional life interference. Pre-tenure men’s desire to stay in their job and career satisfaction remained high, regardless of the number of professional life interferences they experienced. Sharing parenting responsibilities with a partner did not buffer the demands of caregiving on pre-tenure women’s career outcomes. Our work highlights the need to consider the varied ways in which caregiving affects faculty members’ careers, beyond markers such as publications, and how institutions can support early career stage women with family-friendly practices.

Specific and cumulative lifetime stressors in the aetiology of major depression: A longitudinal community-based population study

AIMS

Early-life stressful circumstances (i.e. childhood maltreatment) coupled with stressful events later in life increase the likelihood of subsequent depression. However, very few studies have been conducted to examine the specific and cumulative effects of these stressors in the development of depression. There is also a paucity of research that simultaneously considers the role of biological factors combined with psychosocial stressors in the aetiology of depression. Guided by the biopsychosocial model proposed by Engel, the present study aims to examine to what extent the experience of stressors across the lifespan is associated with depression while taking into account the role of genetic predispositions.

METHODS

Data analysed were from the Social and Psychiatric Epidemiology Catchment Area of the Southwest of Montreal (ZEPSOM), a large-scale, longitudinal community-based cohort study. A total of 1351 participants with complete information on the lifetime diagnoses of depression over a 10-year follow-up period were included in the study. Stressful events across the lifespan were operationalised as specific, cumulative and latent profiles of stressful experiences. Latent profile analysis (LPA) was used to explore the clustering of studied stressors including childhood maltreatment, poor parent-child relationship, and stressful life events. A polygenetic risk score was calculated for each participant to provide information on genetic liability. Multivariate logistic regression was used to examine the association between specific, cumulative and latent profiles of stressors and subsequent depression.

RESULTS

We found that different subtypes of childhood maltreatment, child-parent bonding and stressful life events predicted subsequent depression. Furthermore, a significant association between combined effects of cumulative stressful experiences and depression was found [odds ratio (OR) = 1.20, 95% confidence interval (CI): 1.12-1.28]. Three latent profiles of lifetime stressors were identified in the present study and named as 'low-level of stress' (75.1%), 'moderate-level of stress' (6.8%) and 'high-level of stress' (18.1%). Individuals with a 'high-level of stress' had a substantially higher risk of depression (OR = 1.80, 95% CI: 1.08-3.00) than the other two profiles after adjusting for genetic predispositions, socio-demographic characteristics, and health-related factors.

CONCLUSIONS

While controlling for genetic predispositions, the present study provides robust evidence to support the independent and cumulative as well as compositional effects of early- and later-on lifetime psychosocial stressors in the subsequent development of depression. Consequently, mental illness prevention and mental health promotion should target the occurrence of stressful events as well as build resilience in people so they can better cope with stress when it inevitably occurs.

Depressive symptoms predict smoking cessation in a 20-year longitudinal study of adult twins

Depression has been suggested to hinder smoking cessation, especially when co-occurring with nicotine dependence. The study aimed to examine the longitudinal association of depressive symptoms with smoking cessation among daily smokers. The study utilized adult Finnish twin cohort where 1438 daily smokers (mean age: 38.3, range: 33-45) in 1990 were re-examined for their smoking status in 2011. We assessed baseline depressive symptoms with the Beck Depression Inventory, and the self-reported smoking status at follow-up. The methods included multinomial logistic regression and time to event analyses, adjusted for multiple covariates (age, sex, marital status, social class, heavy drinking occasions, and health status) and smoking heaviness at baseline assessed by cigarettes per day (CPD). Additionally, within-twin-pair analyses were conducted. Results indicated that moderate/severe depressive symptoms at baseline were associated with a lower likelihood of smoking cessation two decades later. Adjusting for covariates, those with moderate/severe depressive symptoms (vs. no/minimal depressive symptoms) had 46% lower likelihood of quitting (relative risk ratio, RRR = 0.54, 95% CI: 0.30-0.96). After including CPD, the association of depressive symptoms with smoking cessation attenuated modestly (RRR = 0.62, 95% CI: 0.34-1.12). Further, time to event analysis for quitting year since baseline yielded similar findings. In the within-pair analysis, depressive symptoms were not associated with quitting smoking. The results suggest that reporting more depressive symptoms is associated with a lower likelihood of smoking cessation during a 20-year period. The baseline amount of smoking and familial factors partly explain the observed association. Smoking cessation programs should monitor depressive symptoms.

Long-term leisure-time physical activity and other health habits as predictors of objectively monitored late-life physical activity - A 40-year twin study

Moderate-to-vigorous physical activity (MVPA) in old age is an important indicator of good health and functional capacity enabling independent living. In our prospective twin cohort study with 616 individuals we investigated whether long-term physical activity assessed three times, in 1975, 1982 and 1990 (mean age 48 years in 1990), and other self-reported health habits predict objectively measured MVPA measured with a hip-worn triaxial accelerometer (at least 10 hours per day for at least 4 days) 25 years later (mean age of 73 years). Low leisure-time physical activity at younger age, higher relative weight, smoking, low socioeconomic status, and health problems predicted low MVPA in old age in individual-based analyses (altogether explaining 20.3% of the variation in MVPA). However, quantitative trait modeling indicated that shared genetic factors explained 82% of the correlation between baseline and follow-up physical activity. Pairwise analyses within monozygotic twin pairs showed that only baseline smoking was a statistically significant predictor of later-life MVPA. The results imply that younger-age physical activity is associated with later-life MVPA, but shared genetic factors underlies this association. Of the other predictors mid-life smoking predicted less physical activity at older age independent of genetic factors.

Rapid socio-economic changes, psychosocial factors and prevalence of hypertension among men and women aged 55 years at baseline in Estonia: a 13-year follow-up study

BACKGROUND

Hypertension is an important public health problem which causes premature morbidity and mortality. Cardiovascular diseases are responsible for about 55% of deaths in Estonia.

THE PURPOSE OF THE STUDY

was to assess, through a follow-up period, the prevalence of hypertension and to observe which risk factors of cardiovascular disease impact the occurrence of the disease. The second aim of the study was to evaluate the role of psychosocial factors and personality traits among individuals with a diagnosis of hypertension.

MATERIALS AND METHODS

The 330 subjects from Estonia, aged 55 years at baseline, from among whom 219 participated at follow-up. A cross-sectional study based on a self-reported questionnaire was conducted.

RESULTS

Over 13 years, the prevalence of hypertension increased from 4% to 53%. Obese (body mass index ≥30 kg/m²) individuals were four times more likely to belong to the hypertension group (p < .01). Among individuals with hypertension the depressed mood score was ≥4 points (max. 9 points) in 54.3% of participants. Depressed mood was linked with experiencing negative stressful life events (B = 0.047, 95% CI 0.016; 0.079; p < .01). Mastery had a protective impact on depressed mood. The self-rated quality of life score was lower among subjects with hypertension than among those who were not diagnosed with hypertension (p < .05).

CONCLUSIONS

According to the 13-year follow-up study, rapid socio-economic changes in Estonia have affected psychosocial health factors among 55-year-old individuals with a diagnosis of hypertension. There is a significant relationship between obesity and the development of hypertension.

Smoking status as a predictor of antidepressant medication use

BACKGROUND

Cigarette smoking and depression are major public health concerns, but longitudinal research on the association between smoking and antidepressant use is scarce. The purpose of this study was to investigate, whether smoking predicts antidepressant medication during a 10-year follow-up.

METHODS

A questionnaire was administered to Finnish adult twins in 1990. Antidepressant prescription data during 1995-2004 were obtained from the register of the Finnish Social Insurance Institution and linked to the survey data. Cox Proportional Hazard Models among 10,652 individuals (1075 cases, 9577 controls) assessed the risk for depression in the cohort, whereas within-pair comparisons of smoking twins with their non-smoking co-twins controlled for shared familial influences.

RESULTS

Daily smokers had a significantly elevated likelihood for having antidepressant prescriptions in the follow-up. Based on the analysis among those without baseline depression, heavy daily smokers had a significantly elevated likelihood (HR 1.56, 95% CI 1.17-2.08) for antidepressant prescription when adjusted for all confounders. Similar analysis using pairs discordant for antidepressant medication confirmed that daily smoking twins had a higher likelihood for prescriptions (HR 1.98, 95% CI 1.11-3.54) compared with their non-smoking co-twins. The estimates were for MZ pairs (HR 1.78, 95% CI 0.48-6.55) and DZ pairs (HR 1.92, 95% CI 0.99-3.72), respectively.

LIMITATIONS

Changes in smoking status after baseline cannot be accounted for. Reversed association between depression and smoking cannot be ruled out.

CONCLUSION

Daily smoking predicts antidepressant medication, even when controlling for essential confounders and familial factors. This study highlights the need of systematically assessing depressive symptoms among smokers.

Persistent leisure-time physical activity in adulthood and use of antidepressants: A follow-up study among twins

BACKGROUND

To study whether persistent leisure-time physical activity (PA) during adulthood predicts use of antidepressants later in life.

METHODS

The Finnish Twin Cohort comprises same-sex twin pairs born before 1958, of whom 11 325 individuals answered PA questions in 1975, 1981 and 1990 at a mean age of 44 years (range 33-60). PA volume over 15-years was used as the predictor of subsequent use of antidepressants. Antidepressant use (measured as number of purchases) for 1995-2004 were collected from the Finnish Social Insurance Institution (KELA) prescription register. Conditional logistic regression was conducted to calculate odds ratios (OR) with 95% confidence intervals (CI) for the use of antidepressants in pairs discordant for PA (642, including 164 monozygotic (MZ) pairs).

RESULTS

Altogether 229 persons had used at least one prescribed antidepressant during the study period. Active co-twins had a lower risk (unadjusted OR 0.80, 95%CI 0.67-0.95) for using any amount of antidepressants than their inactive co-twins; trends being similar for DZ (0.80, 0.67-0.97) and MZ pairs (0.78, 0.51-1.17). The lowest odds ratio (0.51, 0.26-0.98) was seen among MZ pairs after adjusting for BMI, smoking and binge drinking. The point estimates were similar but non-significant for long-term antidepressant use (4+purchases equivalent to 12 months use).

LIMITATIONS

Self-reported physical activity and low number of discordant MZ pairs.

DISCUSSION

Use of antidepressants was less common among physically active co-twins even when shared childhood experiences and genetic background were controlled for. Physical activity in midlife may therefore be important in preventing mild depression later in life.

Physical activity in adulthood: genes and mortality

Observational studies report a strong inverse relationship between leisure-time physical activity and all-cause mortality. Despite suggestive evidence from population-based associations, scientists have not been able to show a beneficial effect of physical activity on the risk of death in controlled intervention studies among individuals who have been healthy at baseline. On the other hand, high cardiorespiratory fitness is known to be a strong predictor of reduced mortality, even more robust than physical activity level itself. Here, in both animals and/or human twins, we show that the same genetic factors influence physical activity levels, cardiorespiratory fitness, and risk of death. Previous observational follow-up studies in humans suggest that increasing fitness through physical activity levels could prolong life; however, our controlled interventional study with laboratory rats bred for low and high intrinsic fitness contrast with these findings. Also, we find no evidence for the suggested association using pairwise analysis among monozygotic twin pairs who are discordant in their physical activity levels. Based on both our animal and human findings, we propose that genetic pleiotropy might partly explain the frequently observed associations between high baseline physical activity and later reduced mortality in humans.

Early-life adversity and adolescent depression: mechanisms involving the ventral striatum

Early-life adversity is a well-established risk factor for the development of depression later in life. Here we discuss the relationship between early-life adversity and depression, focusing specifically on effects of early-life caregiver deprivation on alterations in the neural and behavioral substrates of reward-processing. We also examine vulnerability to depression within the context of sensitive periods of neural development and the timing of adverse exposure. We further review the development of the ventral striatum, a limbic structure implicated in reward processing, and its role in depressive outcomes following early-life adversity. Finally, we suggest a potential neurobiological mechanism linking early-life adversity and altered ventral striatal development. Together these findings may help provide further insight into the role of reward circuitry dysfunction in psychopathological outcomes in both clinical and developmental populations.

Poor sleep predicts symptoms of depression and disability retirement due to depression

BACKGROUND

Disturbed sleep is associated with mood disorders. Both depression and insomnia may increase the risk of disability retirement. The longitudinal links among insomnia, depression and work incapacity are poorly known.

METHODS

We examined association of self-reported sleep quality with incident symptoms of depression and disability retirement due to depressive disorders in a longitudinal population-based sample of twins (n=12,063 individuals). These adults were categorized by their sleep quality in 1975 and 1981, excluding individuals with depressed mood in 1975/1981. The outcomes were the Beck Depression Inventory (BDItot) and its subscale Negative Attitudes Towards Self (BDINATS) in 1990 as dichotomized measures, and the incidence of disability retirement due to depressive disorder during 1991-2004.

RESULTS

Onset of poor sleep between 1975 and 1981 predicted incident depression (BDItot OR=4.5, 95% CI: 2.7-7.4, BDINATS OR=2.0, 95% CI: 1.4-2.7), while persistent poor sleep showed somewhat weaker effects (BDItot; OR=2.5, 95% CI: 1.0-6.0, BDINATS OR=1.9, 95% CI: 1.1-3.3). Among those with few recent stressful life events, onset of poor sleep predicted strongly depression (BDINATS OR=9.5, 95% CI: 3.7-24.2). Likewise onset of poor sleep by 1981 increased the risk of disability retirement due to depression (OR=2.9, 95% CI: 1.8-4.9) with a similar risk among those with persistent poor sleep (OR=2.7, 95% CI: 1.3-5.7).

LIMITATIONS

Lack of baseline diagnostic interviews; sleep quality based on self-report.

CONCLUSIONS

Poor sleep is of importance in etiology of depression and disability retirement due to depression. This emphasizes the importance of early detection and treatment of sleep disturbances.

Acute and long-term psychiatric side effects of mefloquine: a follow-up on Danish adverse event reports

BACKGROUND

The aim of the study was to explore the profile of acute and long-term psychiatric side effects associated with mefloquine.

METHODS

Subjects (n = 73) reported to a Danish national register during five consecutive years for mefloquine associated side effects were included. Acute psychiatric side effects were retrospectively assessed using the SCL-90-R and questions based on Present State Examination (PSE). Subjects reporting suspected psychotic states were contacted for a personal PSE interview. Electronic records of psychiatric hospitalizations and diagnoses were cross-checked. Long-term effects were evaluated with SF-36. SCL-90-R and SF-36 data were compared to age- and gender matched controls.

RESULTS

In the SCL-90-R, clinically significant scores for anxiety, phobic anxiety and depression were found in 55%, 51%, and 44% of the mefloquine group. Substantial acute phase psychotic symptoms were found in 15% and were time-limited. Illusions/hallucinations were more frequently observed among women. Cases of hypomania/mania in the acute phase were 5.5%. Significant long-term mental health effects were demonstrated for the SF-36 subscales mental health (MH), role emotional (RE), and vitality (VT) in the mefloquine group compared to matched controls.

CONCLUSION

The most frequent acute psychiatric problems were anxiety, depression, and psychotic symptoms. Data indicated that subjects experiencing acute mefloquine adverse side effects may develop long-term mental health problems with a decreased sense of global quality of life with lack of energy, nervousness, and depression.

Association between depression, examination-related stressors, and sense of coherence: the Ronin-Sei study

AIMS

In the Japanese education system, students who fail university entrance exam often go to special preparatory schools to prepare for the following year's exam. These students are called ronin-sei. The purpose of this study was to clarify: (i) depression and somatic complaints in ronin-sei; and (ii) the association between depression, examination-related stressors, and sense of coherence (SOC).

METHODS

A total of 914 ronin-sei from two preparatory schools were asked to answer a self-rating questionnaire. Depression was measured using the Center for Epidemiologic Studies Depression Scale (CES-D) and SOC was measured using the SOC-13 Scale.

RESULTS

Overall, 57.9% of subjects were considered to have depression (CES-D ≥ 16) and 19.8% had severe depression (CES-D ≥ 26). Higher CES-D scores were associated with a higher rate of somatic complaints. In hierarchical logistic regression analysis, having no one to talk to about his/her worries and having parents who disagree about the first-choice of university and faculty were independent risk factors for depression and severe depression, respectively, even after controlling for SOC.

CONCLUSIONS

Preparatory school students have various somatic complaints, and their depression is in part related to examination-related stressors. To maintain mental health, it is important to enhance SOC, to understand their examination-related stressors and to provide adequate support for these students.

Older persons' lived experiences of depression and self-management

Mental ill-health, such as depression in the elderly, is a complex issue that is influenced by the life-world perspective of older persons. Their self-management ability should be strengthened based on an understanding of their situation, perspectives, and vulnerability. The aim of this study was to explore and increase understanding of old persons' lived experiences of depression and self-management using an interpretative explorative design. Understanding was developed by means of hermeneutic interpretation. One theme, Relationships and Togetherness, and four subthemes, A Sense of Carrying a Shoulder Bag, Walking on Eggshells, Holding the Reins, and Estrangement--a Loss of Togetherness, emerged. A collaborative approach can be important for empowering older persons through self-development and management. Although the findings of the present study cannot be considered conclusive or definitive, they nevertheless contribute new knowledge of older persons' lived experiences of depression in everyday life.

Older persons' experiences of depressive ill-health and family support

The aim of this study was to explore experiences of the meaning of family support among older persons with depressive ill-health. Data were collected from twenty-nine participants through semistructured interviews and analysed using interpretative hermeneutic and reflective methodology. The findings revealed a main theme, hovering between feelings of belongingness and aloneness in relationships with family members, based on two themes: a sense of being worthy and a sense of being unworthy. Experiences of support and lack of support from family members were not opposites but connected in internal relationships and can be pictured as a movement on a continuum of ambiguity. Family support promotes the emotional needs of older persons with depressive ill-health to be confirmed. The family plays a vital role, not always by direct assistance, but indirectly by supporting the older person's own "guiding principles" for managing her/his situation. The feelings of aloneness as well as shame and guilt at poor or absent family responsiveness should be adequately addressed. Innovative nursing care can lead to improvement by focusing on acquiescence to the older person's life situation.

Self-reported rather than registered cancer is associated with psychosocial strain

Background

Individuals with only a subjective experience of cancer may conceal severe psychological distress and act like patients with verified disease. The purpose of the study was to establish whether some typical psychosocial factors may be linked to subjects with registered cancer (confirmed) and also to those with self-reported cancer lacking accompanying registered data (non-confirmed).

Methods

The material comprised 25 898 working-aged individuals (response rate 40.0%) in 1998. Of these 19 629 also responded at the follow-up in 2003 (response rate 75.8%). The analyses focused on respondents with cancer diagnosis in 2002 or earlier according to data of the Finnish Cancer Registry and self-report of cancer in 2003 (confirmed) (N=330) and on respondents with self-reported cancer only but lacking registered diagnosis (non-confirmed) (N=140). Those who neither reported cancer nor had a diagnosis were included as a control group (N= 18 299).

Results

Respondents with confirmed cancer belonged more often to the oldest age-group than those with non-confirmed cancer. Respondents with non-confirmed cancer were more often obese, depressed and reported less social support compared to subjects with confirmed cancer. Compared to controls they had a statistically significantly increased risk of depression, lower optimism, lower life satisfaction, more childhood adversities, more negative life events and less social support.

Conclusions

Individuals with only a subjective experience of cancer reported more psychosocial strain than those with accompanying registered cancer. Self-report of a severe disease like cancer without corresponding clinical findings might reflect heavy psychological distress which should be taken into consideration in clinical work.

Heritability and mortality risk of insomnia-related symptoms: a genetic epidemiologic study in a population-based twin cohort

STUDY OBJECTIVES

Our aim was to estimate heritability in phenotypic insomnia and the association between insomnia and mortality.

DESIGN

Representative follow-up study.

PARTICIPANTS

1990 survey of the Finnish Twin Cohort (N = 12502 adults; 1554 monozygotic and 2991 dizygotic twin pairs).

MEASUREMENTS

Current insomnia-related symptoms (insomnia in general, difficulty in initiating sleep, sleep latency, nocturnal awakening, early morning awakening, and non-restorative sleep assessed in the morning and during the day) were asked. Latent class analysis was used to classify subjects into different sleep quality classes. Quantitative genetic modelling was used to estimate heritability. Mortality data was obtained from national registers until end of April 2009.

RESULTS

The heritability estimates of each symptom were similar in both genders varying from 34% (early morning awakening) to 45% (nocturnal awakening). The most parsimonious latent class analysis produced 3 classes: good sleepers (48%), average sleepers (up to weekly symptoms, 40%), and poor sleepers (symptoms daily or almost daily, 12%). The heritability estimate for the cluster was 46% (95% confidence interval 41% to 50%). In a model adjusted for smoking, BMI, and depressive symptoms, the all-cause mortality of poor sleepers was elevated (excess mortality 55% in men and 51% in women). Further adjustment for sleep length, use of sleep promoting medications, and sleep apnea-related symptoms did not change the results.

CONCLUSIONS

Insomnia-related symptoms were common in both genders. The symptoms and their clusters showed moderate heritability estimates. A significant association was found between poor sleep and risk of mortality, especially in those with somatic disease.

Childhood adversities, adulthood life events and depression

BACKGROUND

The role of childhood adversities in predicting adulthood depression has been suggested to be complex and in need of additional comprehensive studies.

AIMS

This investigation set out to examine whether increased exposure to life events (LEs) in adulthood mediates the association between childhood adversities and adulthood depression.

METHODS

This study is based on a random health survey sample from the Finnish working-aged population (n=16,877) with a follow-up of up to 7 years. Depression was identified by Beck Depression Inventory, records of antidepressant prescriptions and hospitalization due to depression obtained from national health registers.

RESULTS

Childhood adversities were associated with an increased likelihood of experiencing a high number of LEs in adulthood and their perceived burdensomeness. The mean number of new LEs correlated significantly (P<0.001) in a dose-response relationship with the number of childhood adversities. Reporting childhood adversities was associated with a 1.28-2.70-fold increase in the odds of depression as indicated by BDI score, a 1.29-1.94-fold increase in the rate of antidepressant prescriptions and a 1.17-4.04-fold increase in the risk of hospitalization due to depression. Adjustment for new LE attenuated these associations by 21-24%, but did not render them insignificant.

CONCLUSIONS

Increased exposure to adult negative life events proximal to adult depression may partially explain the association between childhood adversities and adult depression.

Genetic contribution to the relationship between personality and depressive symptoms among older women

BACKGROUND

Prior studies suggest that certain types of personality are at higher risk for developing depressive disorders. This study examined the relationship between old age depressive symptoms and two middle-age personality dimensions, neuroticism and extraversion.

METHOD

The present study is part of the Finnish Twin Study on Aging, where altogether 409 female twins who had completed the Eysenck Personality Inventory at the age of 38-51 years were studied for depressive symptoms 28 years later using Center for the Epidemiologic Studies Depression Scale. Logistic regression analysis suitable for dependent data and univariate and Cholesky models for decomposing the genetic and environmental factor were used.

RESULTS

Middle age extraversion protected from later depressive symptoms while neuroticism increased the risk. Twin modeling indicated that the association between neuroticism and depressive symptoms resulted from shared genetic risk factors common to both traits. However, a substantial proportion of the genetic vulnerability was specific to old age depressive symptoms and was not shared with neuroticism. Middle age extraversion had no genetic relationship with old age depressive symptoms.

CONCLUSIONS

The relationship between middle age neuroticism and old age depressive symptoms is strong but only partly the result of genetic factors that predispose to both neuroticism and depressive symptoms. Extraversion, by contrast, has no genetic relationship with depressive symptoms experienced in old age.

Measurement Invariance and Latent Mean Differences of the Beck Depression Inventory II Across Gender Groups

This study examined measurement invariance (i.e., configural invariance, metric invariance, scalar invariance) of the Chinese version of Beck Depression Inventory II (BDI-II-C) across college males and females and compared gender differences on depression at the latent factor mean level. Two samples composed of 402 male college students and 595 female college students were analyzed. Results found the evidences of partial scalar invariance of the BDI-II-C with five noninvariant items (i.e., Items 2, 3, 4, 7, and 10), providing empirical evidences of construct validity of the BDI-II-C for the purpose of making gender latent mean comparisons. Additionally, the findings revealed significant latent mean differences favoring females on the Negative Attitude factor but not on the Performance Difficulty and Somatic Element factors. These results were discussed in light of the benefits of using latent mean analyses associated with specific factors when comparing gender differences on depression.

Binge drinking and depressive symptoms: a 5-year population-based cohort study

BACKGROUND

Only few prospective population studies have been able so far to investigate depression and drinking patterns in detail. Therefore, little is known about what aspect of alcohol consumption best predicts symptoms of depression in the general population.

PARTICIPANTS AND DESIGN

In this prospective population-based two-wave cohort study, a cohort of alcohol-drinking men and women (n = 15 926) were followed-up after 5 years. A postal questionnaire was sent in 1998 (response proportion 40%) and again in 2003 (response proportion 80% of the baseline participants) to Finnish adults aged 20-54 years at baseline.

MEASUREMENTS

Alcohol consumption was measured by average intake (g/week) and by measures of binge drinking (intoxications, hangovers and alcohol-induced pass-outs). Depressive symptoms were assessed with the 21-item Beck Depression Inventory. In addition, information from hospital discharge register for depression and alcohol abuse were linked to the data.

FINDINGS

This study found a positive association between baseline binge drinking and depressive symptoms 5 years later. Adjustment for several possible confounders attenuated the observed relationships only slightly, suggesting that binge drinking contributes independently to the occurrence of depressive symptoms. Binge drinking was related to symptoms of depression independently of average intake.

CONCLUSIONS

This study supports the hypothesis that heavy drinking, and in particular a binge pattern involving intoxications, hangovers or pass-outs, produces depressive symptoms in the general population. The frequency of hangovers was the best predictor for depressive symptoms.

Risk factors of suicide in inpatients and recently discharged patients with affective disorders. A case-control study

OBJECTIVE

Patients with affective disorders are at high risk of suicide, especially during inpatient treatment and during the first year after discharge.

METHODS

A blinded case-control design was used. The study included a total national sample of patients with affective disorder admitted during the period from January 1, 1994 to December 31, 1995, who died because of suicide, either during admission or shortly after discharge.

RESULTS

A history of suicide attempt was a significant risk factor (IRR 4.9; 95% CI 2.1-11.6). Loss of job during the year prior to the index admission was associated with an increase in suicide risk (IRR: 2.9; 95% CI 1.2-7.5). Clinical improvement during the index admission (IRR: 0.3; 95% CI 0.1-0.7), and treatment with antidepressant drugs at the censoring date (IRR: 0.3; 95% CI 0.1-0.7) were associated with a decrease in suicide risk.

CONCLUSION

Improved treatment may be a key factor in suicide prevention in patients during, and shortly after hospitalisation with affective disorders. Also, there is a need to be especially aware of suicide risk in patients with little or no improvement at discharge.

Life events, anxious depression and personality: a prospective and genetic study

BACKGROUND

The association between life events and anxious depression might be due to causality or to gene-environment correlation. We examined unidirectional and reciprocal causality and a gene-environment correlation model, in which genes that influence the vulnerability for anxious depression also increase the risk of exposure to life events. The effect of genes that influence environmental exposure might be mediated through personality and we therefore also examined the association between life events and personality (neuroticism and extraversion).

METHOD

Information on life events, anxious depression, neuroticism and extraversion was collected in 5782 monozygotic (MZ) and dizygotic (DZ) twins who participated in a longitudinal survey study of the Netherlands Twin Register. To examine causality, data were analysed longitudinally. To examine gene-environment correlation, the co-twin control method was used.

RESULTS

Anxious depression and, to a lesser extent, neuroticism scores increased after exposure to life events. Anxious depression and neuroticism also predicted the experience of life events. Prospectively, extraversion was not associated with life events. Anxious depression, neuroticism and extraversion scores did not differ between the non-exposed subjects of MZ and DZ twin pairs and unrelated subjects discordant for life events.

CONCLUSIONS

Our findings suggest that reciprocal causation explains the relationship between life events and anxious depression and between life events and neuroticism. Extraversion is not related to life events. No evidence was found for gene-environment correlation, i.e. the genes that influence anxious depression, neuroticism or extraversion do not overlap with the genes that increase the risk of exposure to life events.

The genetic liability to disability retirement: a 30-year follow-up study of 24,000 Finnish twins

Background

No previous studies on the effect of genetic factors on the liability to disability retirement have been carried out. The main aim of this study was to investigate the contribution of genetic factors on disability retirement due to the most common medical causes, including depressive disorders.

Methods

The study sample consisted of 24 043 participants (49.7% women) consisting of 11 186 complete same-sex twin pairs including 3519 monozygotic (MZ) and 7667dizygotic (DZ) pairs. Information on retirement events during 1.1.1975–31.12.2004, including disability pensions (DPs) with diagnoses, was obtained from the Finnish nationwide official pension registers. Correlations in liability for MZ and DZ twins and discrete time correlated frailty model were used to investigate the genetic liability to age at disability retirement.

Results

The 30 year cumulative incidence of disability retirement was 20%. Under the best fitting genetic models, the heritability estimate for DPs due to any medical cause was 0.36 (95% CI 0.32–0.40), due to musculoskeletal disorders 0.37 (0.30–0.43), cardiovascular diseases 0.48 (0.39–0.57), mental disorders 0.42 (0.35–0.49) and all other reasons 0.24 (0.17–0.31). The effect of genetic factors decreased with increasing age of retirement. For DP due to depressive disorders, 28% of the variance was explained by environmental factors shared by family members (95% CI 21–36) and 58% of the variance by the age interval specific environmental factors (95% CI 44–71).

Conclusions

A moderate genetic contribution to the variation of disability retirement due to any medical cause was found. The genetic effects appeared to be stronger at younger ages of disability retirement suggesting the increasing influence of environmental factors not shared with family members with increasing age. Familial aggregation in DPs due to depressive disorders was best explained by the common environmental factors and genetic factors were not needed to account for the pattern of familial aggregation.

Personality disorders and perceived stress in major depressive disorder

The investigation of comorbidity between major depressive disorder (MDD) and personality disorders (PDs) has attracted considerable interest. Whereas some studies found that the presence of PDs has adverse effects on the course and treatment of MDD, others have failed to demonstrate this link. These inconsistent findings suggest that specific PD comorbidity might affect the course of MDD by modulating factors that increase the overall risk of depression, including an elevated tendency to perceive stress. To investigate whether the presence of a specific PD cluster was associated with elevated levels of stress appraisal, we administered the Perceived Stress Scale (PSS) before and after treatment to 227 MDD outpatients enrolled in an 8-week open-label treatment with fluoxetine. Following treatment, multiple linear regression analyses revealed that the presence of Cluster A, but not Cluster B or C, was associated with higher levels of perceived stress, even after adjusting for baseline depression severity and PSS scores, as well as various sociodemographic variables. The presence of Cluster A PD comorbidity was uniquely associated with elevated stress appraisal after antidepressant treatment, raising the possibility that stress exacerbation might be an important factor linked to poor treatment outcome in MDD subjects with Cluster A pathology.

Adolescent risk factors for episodic and persistent depression in adulthood. A 16-year prospective follow-up study of adolescents

BACKGROUND

We examined mid-adolescent psychosocial problems as risk factors for subsequent depression up to adulthood proper, and differences in these for episodic and persistent depression.

METHODS

In a 16-year follow-up of an urban Finnish community cohort (547 males and 714 females) from age 16 years risk factors for subsequent depression (S-BDI) were studied. Data were collected with a classroom questionnaire at 16 years and a postal questionnaire at 22 and 32 years. Differences in predictors for episodic depression (only at age of 22 or 32 y) and persistent depression (both at 22 and 32 y) were studied using logistic and multinomial regression analyses.

RESULTS

Mid-adolescent depressive symptoms predicted persistent and female sex episodic depression. Low self-esteem, dissatisfaction with academic achievement, problems with the law, having no dating experiences, and parental divorce all predicted both episodic and persistent depression.

LIMITATIONS

We had two assessment points in adulthood, but no information about depression between these.

CONCLUSIONS

The associations between mid-adolescent psychosocial problems and subsequent depression extended up to adulthood proper, somewhat differently for episodic and persistent depression. Preventive efforts should be focused towards young people at risk.

Work related violence and threats and the risk of depression and stress disorders

OBJECTIVE

To examine the risk of depression and stress related disorders as a function of occupational exposure to violence and threats.

DESIGN

Population based nested case-control study.

SETTING

All gainfully employed Danes. Cases and controls: 14 166 hospital inpatients and outpatients, aged 18-65, treated for affective or stress related disorders during 1995-1998 selected from The Danish Psychiatric Central Research Register and 58 060 controls matched for age, sex, and time, drawn from Statistics Denmark's Integrated Database for Labour Market Research.

MAIN OUTCOME MEASURE

Clinical psychiatric diagnosis (WHO ICD-10) of affective (F30-39) or stress related (F40-48) disorders compared with controls by the occupation held the year before treatment. The occupation held the year before treatment was used as exposure proxy.

RESULTS

Potential exposure to occupational violence is associated with significantly increased relative risks of both disorders in either sex (women: depression RR 1.45 CI 1.27 to 1.65, stress RR 1.32 CI 1.19 to 1.46; men: depression RR 1.48 CI 1.18 to 1.86, stress RR 1.55 CI 1.29 to 1.84). Work related threats are associated with increase in the risk of depression in women (RR 1.48 CI 1.23 to 1.79) and the risk of stress related disorders in men (RR 1.59 CI 1.32 to 1.91). Risks rose with increasing prevalence of violence and threats. The results remain significant and only slightly attenuated after controlling for extent of professional contact with people other than colleagues.

CONCLUSIONS

Employment in occupations involving exposure to work related threats and violence is a risk factor for depression and stress related disorders in both sexes. These findings have implications for health and safety at work policies.

Which factors are important predictors of non-recovery from major depression? A 2-year prospective observational study

Our aim was to study factors associated with long-term non-recovery from major depression. A total of 109 patients with major depression were followed prospectively for 2 years. A diagnosis of major depression based on SCID interviews at follow-up indicated non-recovery. The effect of several established risk factors was assessed. A third (30%) of the patients did not recover. Severity of initial depression were associated with poor outcome according to univariate analysis. Nevertheless, personality disorder and rural area of residence were associated with non-recovery in final multivariate analysis. Major depression in patients with personality disorder should be treated as effectively as possible. Moreover, service planning in rural areas needs attention.

Recovery from depression: a two-year follow-up study of general population subjects

BACKGROUND

The recovery from depression and factors associated with it are not well known in the general population.

AIMS

To conduct a two-year follow-up of general population subjects and investigate their recovery from depression.

METHODS

Individuals who were assessed as suffering from depression on the basis of Beck Depression Inventory (BDI) scores were monitored for two years.

RESULTS

Sixty-five per cent were still depressed after two years of follow-up. Negative life events had occurred more often in those who had remained depressed than in the others. Logistic regression analysis revealed that a high initial BDI score and a worsening of a subject's economic situation during the follow-up period were associated with failure to recover. Lack of use of health services was associated with non-recovery.

CONCLUSION

Depression may be more chronic in the general population than previously has been thought.

Childhood adversities, adult risk factors and depressiveness: a population study

OBJECTIVE

Childhood adversities have been associated with adulthood depressiveness, but the contribution of adult risk factors is seldom described. We examined whether adult risk factors lie on the pathway from childhood adversity to adult depressiveness (pathway hypothesis) or whether the association depends on life events (vulnerability hypothesis).

METHOD

Among 21,101 randomly sampled working-aged respondents [the Health and Social Support in Finland (HeSSup) Study], the hypotheses were tested with logistic regression analysis models studying the associations between Beck Depression Inventory (BDI)-assessed depressiveness and self-reported childhood adversities alone and in combination with recent adverse events.

RESULTS

Childhood adversities were consistently associated with depressiveness (women, age-adjusted odds ratio 3.1, 95% confidence intervals 2.6-3.7; men, 2.6, 2.1-3.3), although the risks were decreased by more than 30% after adjustments for adult risk factors such as living alone, education, alcohol consumption, social support and negative affectivity. Childhood adversities combined with recent life events were associated with depressiveness in an additive manner. Women with childhood adversities and recent person-independent events especially had increased vulnerability for depressiveness.

CONCLUSIONS

The childhood adversity-depressiveness associations were partly mediated by adult risk factors, supporting a pathway from childhood adversities to depressiveness through adult risk factors. Increased vulnerability for depressiveness was found among respondents with childhood adversities in combination with recent death/illness events. The findings emphasize the importance of early risk factors when identifying persons at risk of depression.

Adverse childhood experiences, stressful life events or demographic factors: which are important in women's depression? A 2-year follow-up population study

OBJECTIVE

The aim of this study was to simultaneously test adverse background factors, namely adverse childhood experiences (ACEs), stressful life events and prior depressive symptoms, for their ability to predict recovery and non-recovery from depression in women among the general population.

METHOD

A stratified random sample of women (n = 835) from the general population was collected at baseline in 1999. Depression (Beck Depression Inventory, BDI-21), ACEs and background factors were assessed by postal questionnaire at baseline. Two years later, stressful life events during the study phase, social support, use of health services and current depression (BDI > or = 13) were similarly assessed.

RESULTS

Adverse childhood experiences were common among depressed women and these past experiences together with the use of health services were associated with recovery from depression. Financial difficulties and a poor subjective health status associated with non-recovery and current stressful life events increased the likelihood of depression on follow-up. Furthermore, the important variables explaining depression on follow-up were the quality of social support and the existence of prior depressive symptoms at baseline.

CONCLUSIONS

Our results suggest that women's current depression especially associates with stressful life events, insufficient social support, poor subjective health and financial difficulties. It seems possible that past adverse experiences predispose women to depression, but current stressful events actualize these symptoms. In addition, use of health services are associated with recovery in women who had ACEs.

Predicting the onset of major depression in subjects with subthreshold depression in primary care: a prospective study

OBJECTIVE

That subjects with subthreshold depression have an increased probability of developing major depression has been confirmed by many studies. However, the factors which may predict the onset of major depression have yet to be fully examined.

METHOD

We examined the control group of a randomized trial in primary care patients with subthreshold depression (N = 109), of whom 20 had developed major depression 1 year later. Using the vulnerability-stress theory, we examined which factors predicted the onset of major depression.

RESULTS

In both univariate and multivariate analyses, family history and chronic illnesses predicted the onset of major depression.

CONCLUSION

It is possible to predict to a certain degree whether a subject with subthreshold depression will develop major depression within a year.

Recovery from major depression: the role of support from family, friends, and spiritual beliefs

OBJECTIVE

Many of the risk factors for major depression are not amenable to change. The present study was designed to identify factors associated with recovery from depression that could be targets for clinical intervention.

METHOD

Sixty-two psychiatric in-patients who met diagnostic criteria for major depression were interviewed while hospitalized and re-interviewed 3 months after discharge. Analyses examined the relationship between depression and three sources of emotional support: family, friends, and spiritual beliefs.

RESULTS

Depression severity at baseline was the most consistent predictor of depression severity and diagnosis at follow-up. Patients who had recovered from depression by the time of the follow-up assessment reported higher perceived emotional support from family and friends at baseline. Support from friends, support from family and a composite of emotional support were significant predictors of depression beyond the effects of initial depression severity.

CONCLUSION

Aspects of emotional support were significantly associated with depression outcome.

The potential relationship between levels of perceived stress and subtypes of major depressive disorder (MDD)

OBJECTIVE

We wanted to explore whether major depressive disorder (MDD) subtypes (melancholic depression, atypical depression, double depression, and MDD with anger attacks) were related to levels of perceived stress, as measured by the Perceived Stress Scale (PSS).

METHOD

Our sample [n = 298; female = 163 (55%); mean age 40.1 +/- 10.5 years] consisted of out-patients with MDD. The Structured Clinical Interview for DSM-III-R, the 17-item Hamilton Rating Scale for Depression, the Anger Attack Questionnaire, and the PSS were administered prior to initiating treatment.

RESULTS

Depressed women had significantly higher levels of perceived stress (P = 0.02) than depressed men. Greater severity of depression at baseline was significantly related to higher levels of perceived stress (P < 0.0001). After adjusting for age, gender, and severity of depression at baseline, higher levels of perceived stress were significantly related to the presence of anger attacks (P < 0.0001; t = -4.103) as well as to atypical depression (P = 0.0013; t = 3.26).

CONCLUSION

Out-patients with MDD who are more irritable and/or present with atypical features have higher levels of perceived stress, indicating a potential reactive component to their depression.

Do stressful life-events or sociodemographic variables associate with depression and alexithymia among a general population?--A 3-year follow-up study

This 3-year follow-up study examined background factors, stressful life-events, and changes in alexithymia and depression scores in four groups of subjects from a general population (N = 1,339): alexithymic (A), depressed (D), simultaneously alexithymic/depressed (AD), and non-alexithymic/non-depressed (O). Alexithymia was assessed using the 20-item version of the Toronto Alexithymia Scale (TAS) and depression using the 21-item Beck Depression Inventory (BDI). A questionnaire screening sociodemography and stressful life-events was also used. The results showed that alexithymia was associated with male gender and blue-collar working, whereas depressive symptoms associated with female gender, older age, poor subjective health, poor financial situation, and low life satisfaction. During the follow-up the sum of stressful life-events was higher among groups AD and D than in groups A and O. The most common stressful life-events were the death of a close relative or friend, a negative change in the health of a family member, and financial problems. The TAS scores decreased only in groups A and AD. The BDI scores decreased in group AD but remained relatively unchanged in group D. Interestingly, if only those without depressive symptoms are considered, alexithymia appears to be a rarer phenomenon than has been reported previously. Furthermore, it seems that depressive symptoms were chronic and long-lasting among the general population.

Psychosocial predictors of successful delivery after unexplained recurrent spontaneous abortions: a cohort study

OBJECTIVE

To examine psychosocial predictors of successful pregnancy after recurrent spontaneous abortions (RSA).

METHOD

We administered two waves of semi-structured interview and self-report questionnaire battery to a consecutive series of 46 couples who had had two RSAs (baseline before third pregnancy, and immediately after third pregnancy was ascertained), and followed them through their third pregnancy.

RESULTS

Of the 46 couples, four miscarried for karyotypal abnormalities and six without any known cause. When the latter six were compared with the remaining 36 women, they reported less social support satisfaction, a more stable attribution for the causes of past abortions, and more depressed mood in the preceding year. Taken altogether, this psychosocial model was able to predict 93% of the pregnancy outcomes correctly.

CONCLUSION

Psychosocial variables (depression, attribution and social support) are robust predictors of the prospective pregnancy and suggest possible points of intervention in couples with RSA.

Determinants of depression among Ethiopian immigrants and refugees in Toronto

The purpose of this study was to determine the occurrence of and risk factors for depressive disorder in a random sample of 342 Ethiopian immigrants and refugees in Toronto. The Composite International Diagnostic Interview questionnaire was used to measure depression. The results suggested a lifetime prevalence of depression among Ethiopian immigrants and refugees of 9.8%, which was slightly higher than the lifetime prevalence rate in the Ontario population (7.3%). However, the rate among Ethiopian immigrants and refugees was approximately three times higher than the rate estimated for Southern Ethiopia (3.2%). The data confirmed the significance of known risk factors for depression in immigrants, including younger age, experiences of premigration trauma, refugee camp internment, and postmigration stressful events. The implication of the overall finding is that there is a need to develop mental health intervention programs, particularly for people who have experienced premigration trauma, refugee camp internment, and postmigration stresses.