Psychiatric Illness Among a Nationally Representative Sample of Sole and Partnered Parents in New Zealand

Abstract

To quantify the excess risk of specific, diagnosable mental illnesses experienced by sole parents in New Zealand, and to estimate the contribution of socioeconomic position (SEP), co-residence with other adults (as a proxy for social and practical support) and physical health status to this excess risk. Data used in the present study were from the New Zealand Mental Health Survey, a nationally representative population-based household survey of 12,992 adults (16+ years) fielded in 2004. The sample included 1216 sole and 3681 partnered parents living with one or more dependent children, with an overall response rate of 73%. Mental illness (12 month prevalence of anxiety, mood, and substance use disorders, and suicidality) was measured with version 3.0 of the Composite International Diagnostic Interview. Illness severity was measured with the Sheehan Disability Scale and the Global Assessment of Functioning Scale. Covariates included household income from all sources, labour market attachment, co-residence with other adults and doctor-diagnosed chronic physical illness. Multiple logistic regression was then carried out on the weighted cross-sectional survey dataset. Adjusting for demographic variables, sole parents had significantly higher 12 month prevalences of mental illnesses than their partnered counterparts, with odds ratios (ORs) of 2.6 (95% confidence interval (CI)=2.0-3.3) for any mental illness, 2.9 (95%CI=2.1-4.0) for any serious mental illness, 2.2 (95%CI=1.7-2.8) for anxiety disorder, 2.6 (95%CI=2.0-3.4) for mood disorder, 3.6 (95%CI=2.2-6.0) for substance use disorder and 2.5 (95%CI=1.5-4.0) for suicidal ideation. Chronic physical illness accounted for only a small proportion of these excess risks. SEP and co-residence of another adult each explained approximately one-quarter of the excess risks and jointly explained approximately half (except for substance use disorders). Almost all of the effect of SEP was mediated by income, with employment status making only a very small independent contribution. The present results confirm the higher prevalence of mental illness experienced by sole parents, underlining the importance of improving access to primary mental health care, including alcohol and drug rehabilitation services, for sole parents. But they also caution against a solely clinical response and highlight a need to better understand and respond to the social and economic processes that lie behind the associations between mental health, socioeconomic position and sole parenthood in New Zealand.