BackgroundTreatment coverage for mental disorders is poor in most developed countries.AimsTo explore some reasons for the poor treatment coverage for mental disorders in developed countries.MethodData were taken from Australian national surveys and from the World Health Report.ResultsOnly one-third of people with a mental disorder consulted. Probability of consulting varied by diagnosis: 90% for schizophrenia, which is accounted for by external factors; 60% for depression; and 15% for substance use and personality disorders. The probability of consulting varied by gender, age, marital status and disability, from 73% among women aged 25–54 years, disabled and once married to 9% among males without these risk factors. Those who did not consult but were disabled or comorbid said that they “preferred to manage themselves”. Data from five countries showed no evidence that overall health expenditure, out-of-pocket cost or responsiveness of the health system affected the overall consulting rates.ConclusionsSocietal, attitudinal and diagnostic variables account for the variation. Funding does not. Public education about the recognition and treatment of mental disorders and the provision of effective treatment by providers might remedy the shortfall.