Much touted "depression risk gene" may not add to risk after all: New look at data confirms strong association between depression and stressful life events

Previous studies have found that stressful life events (SLEs) are associated with increased risk of adult depression. However, many studies are observational in nature and limited by methodological issues, such as potential confounding by genetic factors. Genetically informative studies, such as the co-twin control design, can strengthen causal inference in observational research. The co-twin control design involves comparing patterns of associations in the full sample and within dizygotic (DZ) and monozygotic twins (MZ). Discrete-time survival analysis has several benefits and multilevel survival analysis can incorporate frailty terms (random effects) to estimate the components of the biometric model. In the current study, we investigated associations between SLEs and depression risk in a population-based twin sample (N = 2299) with a co-twin control design. Associations were modelled using discrete-time survival analysis with biometric frailty terms. SLE occurrence was associated with increased depression risk. Co-twin control analyses indicated that this association was at least in part due to causal influence of SLE exposure on depression risk for event occurrence across all SLEs and of violent SLEs. Stronger within-pair estimates for economic SLEs compared with the full sample association could have resulted if the full sample association was suppressed or if within-pair estimates were inflated. If the former occurred, economic SLEs may represent particularly important risk factors for depression. A minor proportion of the total genetic risk of depression reflected genetic effects related to SLEs. Our findings have implications for future research on SLEs and depression.

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Recent and childhood adversities in patients with depressive disorders

European Psychiatry ◽

10.1016/j.eurpsy.2016.01.1459 ◽

2016 ◽

Vol 33 (S1) ◽

pp. S404-S404

Author(s):

M. Abdelhameed ◽

A. Kamal ◽

N. Abdelfadeel ◽

S. Morsy

Keyword(s):

Child Abuse ◽

Life Events ◽

Depressive Disorders ◽

Stressful Life Events ◽

Rating Scale ◽

Strong Association ◽

Severe Depression ◽

Depressive Illness ◽

Stressful Life ◽

Emotional Neglect

IntroductionA strong association is believed to exist between stressful life events and the development of depressive disorders. Childhood adverse experiences contribute to person's vulnerability to such disorders.ObjectiveThe study of the complex interplay between child abuse, stressful life events and the development of depression.AimsTo study the effect of type and severity of child abuse and magnitude of pre-onset stress on the severity and duration of adulthood depression.MethodsSeventy-five patients with depressive disorders not having a comorbid mental illness were studied using Social Readjustment Rating scale (SRRS) and Childhood Trauma Questionnaire (CTQ).ResultsThe mean age of the patients was 34.96 ± 12.32 years, 69.3% of patients were females, duration of the illness ranged from 2–288 weeks with a mean of 30.94 ± 54.61 and 36% of the sample had severe depression. There was a statistically significant relationship between urban residence and magnitude of stress (P = 0.049), married patients suffered less severe depression than unmarried ones (P = 0.02) and a positive and significant correlation was found between magnitude of stress and severity of depression (P ≤ 0.001).Duration of depressive illness was positively and significantly correlated to the raw score of SRRS and to the severity of emotional neglect as measured by CTQ (P = 0.02 and 0.04 respectively).ConclusionsThe development of depression in adulthood is significantly associated with past exposure to child abuse and stressful life events. Childhood history of emotional neglect and magnitude of pre-onset stress may be contributing factors to duration of depressive illness.Disclosure of interestThe authors have not supplied their declaration of competing interest.

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