Prevalence, impairment and severity of 12-month DSM-IV major depressive episodes in Te Rau Hinengaro: New Zealand Mental Health Survey 2003/4.
OBJECTIVE
To assess the prevalence, symptom severity, functional impairment and treatment of major depressive episodes in the New Zealand population, in light of recent criticism that depression is 'over-diagnosed', especially in community surveys.


METHODS
Nationally representative cross-sectional household survey of 12 992 adults (aged 16+): The New Zealand Mental Health Survey 2003/4. 12-month major depressive episode measured in face-to-face interviews with the Composite International Diagnostic Interview (CIDI 3.0).


RESULTS
The 12-month prevalence of major depressive episode (MDE) was 6.6% for the total population, with decreasing prevalence with increasing age, and higher prevalence in females (8.1% versus 4.9% in males). Fewer than 10% of 12-month episodes were classified on a symptom severity rating scale as mild, and 69% of all episodes were accompanied by severe impairment in at least one domain of functioning. Only a third of those with severe impairment received treatment in the mental health sector, and half saw a general medical practitioner.


CONCLUSIONS
These results offer little support for the suggestion that depression is over-diagnosed and over-treated, and that current diagnostic thresholds allow the inclusion of too many mild episodes in community surveys.
Scott
Kate M
KM
Department of Psychological Medicine, University of Otago, Wellington, New Zealand. kate.scott@otago.ac.nz
Oakley Browne
Mark A
MA
Elisabeth Wells
J
J
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006306:Health Surveys; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D015995:Prevalence; D012720:Severity of Illness Index; D012737:Sex Factors