A recent analysis of the German National Cohort (NAKO) shows that people who experienced trauma such as abuse or neglect during their childhood or adolescence were around twice as likely to develop depression in adulthood. The links were particularly pronounced in cases of emotional abuse and neglect. The gender differences in depression appeared to be linked primarily to the fact that women were more frequently exposed to certain forms of distressing childhood experiences, rather than to a greater susceptibility of women to their psychological consequences.
People around the world suffer from the physical and psychological consequences of abuse and neglect during childhood and adolescence – experiences that are collectively referred to as ‘childhood trauma’. “In our study, we investigated whether the various forms of childhood trauma were associated to varying degrees with the burden of depression in adulthood, and whether there were any gender-specific differences,” says Maja Völker, a PhD student in the Department of Genetic Epidemiology in Psychiatry at the Central Institute of Mental Health (CIMH).
In psychology and epidemiology, the term ‘burden of disease’ describes the impact of a mental health condition, such as depression, on the person affected – not only through the symptoms themselves, but also through their consequences for everyday life and quality of life. The researchers, led by the ZI, analysed data from 159,045 participants in the German National Cohort (NAKO) aged between 19 and 72, just under half of whom were women. They distinguished between five forms: emotional, physical and sexual abuse, as well as emotional and physical neglect. Childhood trauma was recorded using a standardised questionnaire. The burden of disease due to depression was determined using three methods: self-reported medical diagnoses, a psychological questionnaire and a standardised interview.
Traumatic childhood experiences more than double the risk of depression
Just under 26 per cent of NAKO participants reported at least one form of childhood trauma. 13 per cent of respondents stated that they had experienced depression at some point in their lives (women: 17.7 per cent; men: 10.1 per cent). 7.5 per cent of participants reported current symptoms of depression (women: 9.0 per cent; men: 5.9 per cent).
Analysis of the data revealed clear links between childhood trauma and mental health: people who had experienced adverse childhood experiences were more than twice as likely to develop depression at some point in their lives. For current – that is, ongoing – depressive symptoms, the risk was almost three times as high. The links between childhood abuse and the burden of disease in adulthood were particularly pronounced in cases of emotional abuse and emotional neglect.
Women reported abuse or neglect more frequently, particularly sexual and emotional forms, whilst men reported physical abuse slightly more often. The analyses also showed that childhood adversity plays a role in a significant proportion of cases of depression: based on the statistical correlations between reported childhood adversity and depressive disorders, childhood adversity was associated with around one in four cases of depression over the course of a lifetime and around one-third of cases with current depressive symptoms – with women affected more frequently than men in both instances. These figures indicate the proportion of cases of depression in the population that can statistically be attributed to childhood adversity; they are not based on participants directly attributing a causal link.
“With regard to the links with adverse childhood experiences, our findings make it clear that the gender difference is not due to a greater susceptibility to subsequent mental health conditions resulting from childhood abuse or neglect, but is rather linked to the fact that women were more frequently exposed to these adverse experiences,” explains psychologist Aina L. Kresken, who contributed to the study as part of her Master’s thesis at the University of Mannheim.
Importance for early prevention
Dr Fabian Streit, a researcher at the Hector Institute for Artificial Intelligence in Psychiatry at the CIMH, summarises: “Our findings suggest that childhood abuse and neglect may be associated with a significant proportion of cases of depression. They thus underline the importance of early prevention and targeted protective measures. In particular, protection against emotional abuse and neglect can make an important contribution to reducing depression in the long term.”
The current analysis takes into account data from NAKO participants at a specific point in time. Supplementary studies, including those using longitudinal data from NAKO, are now intended to explore the identified associations in greater depth and also to take biological, social and behavioural factors into account.