Relationship separation and mental health problems: findings from a 30-year longitudinal study

To examine the associations between relationship separation and a range of mental health problems including depression, anxiety disorders, alcohol abuse/dependence, cannabis abuse/dependence, and total number of mental health problems.

Data were drawn from a 30-year longitudinal study of a birth cohort of individuals born in Christchurch, New Zealand. Associations between separation and mental health problems were examined using two types of regression models: population-averaged generalized estimating equation models and fixed effects models. Associations were adjusted for a wide range of fixed and time-dynamic potential covariate factors.

After due allowance was made for confounding, separation was associated with depression, suicidal behaviour, and the total number of mental health problems (rate ratios range 1.7-3.4, median 3.2). These associations were apparent both when separation was used as the dependent variable and when the mental health problems were used as the dependent variables. In contrast, separation was not significantly associated with anxiety disorders, alcohol abuse/dependence, or illicit drug abuse/dependence when due allowance was made for confounding. Associations between separation and mental health problems were not significantly different for men and women.

Separation of a cohabiting relationship is associated with increased rates of depression, suicidal behaviour, and total mental health problems. However, it was not possible to determine the causal direction of the relationship between separation and mental health problems. Future studies may need to employ approaches other than observational research designs in order to address issues of causality.