Research into the factors associated with common mental disorders (for example, depression and anxiety) generally considers predictors at the level of the individual. Despite growing recognition of environmental and contextual effects on mental health, and awareness of the importance of marital and other close relationships, a relatively small number of studies have investigated the relationship between spousal mental health. Research has demonstrated a moderate correlation between partners' depressive symptoms and other measures of psychological distress, though most studies have used clinical populations and few have examined community-based samples.

This paper investigates the relationship between the mental health of spouses using a large nationally-representative Australian household survey. Data were from the first-wave of the Household Income and Labour Dynamics in Australia (HILDA) Survey. Data were available for 3739 different-sex couples. The analysis used multi-level statistical techniques, as well as logistic regression models with the family the unit of analysis. Analyses examined sources of variance in the data, the effect of demographic factors (age, sex, duration of marriage) and the interaction between partners' mental and physical health.

Variance component analysis showed that 25 percent of variance in mental health scores occurs at the family or partner level. That is, a quarter of the variability in a person's mental health can be attributed to differences between couples. Separate logistic regression models for men and women (dichotomising mental health scores) supported this finding, with partner's mental health problems strongly associated with own experience of mental health problems (odds ratios > 3).

The results demonstrate the interdependence of mental health within couples and the importance of considering relationship and partner circumstances in both research and practice.