Ethnic comparisons of the 12 month prevalence of mental disorders and treatment contact in Te Rau Hinengaro: the New Zealand Mental Health Survey.

Objective: To compare ethnic groups for the 12 month prevalence of mental disorders and 12 month treatment contact in Te Rau Hinengaro: The New Zealand Mental Health Survey.

Method: Te Rau Hinengaro: The New Zealand Mental Health Survey, undertaken in 2003 and 2004, was a nationally representative face-to-face household survey of 12,992 New Zealand adults aged 16 years and over, including Māori (n = 2595), Pacific people (n = 2236) and a composite Other ethnic group (predominantly European) (n = 8161). Ethnicity was measured using the 2001 census ethnicity question. A fully structured diagnostic interview, the World Health Organization World Mental Health Survey Initiative version of the Composite International Diagnostic Interview (CIDI 3.0) was used to measure disorder. The overall response rate was 73.3%.

Results: The 12 month prevalence of any mental disorder was highest in Māori (29.5%; 26.6, 32.4), followed by Pacific people (24.4%; 21.2, 27.6) and Others (19.3%; 18.0, 20.6). Adjustment for age, sex, education and household income reduced differences: Māori (23.9%; 21.3, 26.4), Pacific (19.2%; 16.4, 22.1) and Other (20.3%; 18.9, 21.6). A similar pattern was seen for serious disorder and most individual disorders or disorder groups. After adjustment, Māori were most different from Pacific people and Others for substance use disorder. Both Māori and Pacific people had a higher prevalence of bipolar disorder than Others. Pacific people had the lowest prevalence of major depressive disorder. Among those with disorder, the proportion with a visit for mental health problems to any service was highest among Others (41.1%; 38.1, 44.1), with Māori (32.5%; 28.3, 36.7) intermediate and Pacific (25.4%, 19.4, 31.4) lowest. Adjustment did not alter ethnic differences in service contact.

Conclusion: Māori, and to a lesser extent Pacific people, have a higher prevalence of 12 month mental disorders than Others. Differences are reduced after adjusting for sociodemographic correlates. Relative to need, Pacific people in particular and Māori are less likely than Others to have contact with services (health or non-health), regardless of sociodemographic circumstances.