Background: Previous research has found that mental health is strongly associated with life satisfaction. In this study we examine associations between mental health problems and life satisfaction in a birth cohort studied from 18 to 35 years.
Method: Data were gathered during the Christchurch Health and Development Study, which is a longitudinal study of a birth cohort of 1265 children, born in Christchurch, New Zealand, in 1977. Assessments of psychiatric disorder (major depression, anxiety disorder, suicidality, alcohol dependence and illicit substance dependence) using DSM diagnostic criteria and life satisfaction were obtained at 18, 21, 25, 30 and 35 years.
Results: Significant associations (p < 0.01) were found between repeated measures of life satisfaction and the psychiatric disorders major depression, anxiety disorder, suicidality, alcohol dependence and substance dependence. After adjustment for non-observed sources of confounding by fixed effects, statistically significant associations (p < 0.05) remained between life satisfaction and major depression, anxiety disorder, suicidality and substance dependence. Overall, those reporting three or more mental health disorders had mean life satisfaction scores that were nearly 0.60 standard deviations below those without mental health problems. A structural equation model examined the direction of causation between life satisfaction and mental health problems. Statistically significant (p < 0.05) reciprocal associations were found between life satisfaction and mental health problems.
Conclusions: After adjustment for confounding, robust and reciprocal associations were found between mental health problems and life satisfaction. Overall, this study showed evidence that life satisfaction influences mental disorder, and that mental disorder influences life satisfaction.
Keywords: Fixed-effects regression; life satisfaction; longitudinal studies; mental health; structural equation modelling.