Previous research suggests that many people receiving mental health treatment do not meet criteria for a mental disorder but are rather ‘the worried well’.

To examine the association of past-year mental health treatment with DSM-IV disorders.

The World Health Organization's World Mental Health (WMH) Surveys interviewed community samples of adults in 23 countries (n = 62 305) about DSM-IV disorders and treatment in the past 12 months for problems with emotions, alcohol or drugs.

Roughly half (52%) of people who received treatment met criteria for a past-year DSM-IV disorder, an additional 18% for a lifetime disorder and an additional 13% for other indicators of need (multiple subthreshold disorders, recent stressors or suicidal behaviours). Dose–response associations were found between number of indicators of need and treatment.

The vast majority of treatment in the WMH countries goes to patients with mental disorders or other problems expected to benefit from treatment.

Previous community surveys of the drop out from mental health treatment have been carried out only in the USA and Canada.

To explore mental health treatment drop out in the World Health Organization World Mental Health Surveys.

Representative face-to-face household surveys were conducted among adults in 24 countries. People who reported mental health treatment in the 12 months before interview (n = 8482) were asked about drop out, defined as stopping treatment before the provider wanted.

Overall, drop out was 31.7%: 26.3% in high-income countries, 45.1% in upper-middle-income countries, and 37.6% in low/ lower/middle-income countries. Drop out from psychiatrists was 21.3% overall and similar across country income groups (high 20.3%, upper-middle 23.6%, low/lower-middle 23.8%) but the pattern of drop out across other sectors differed by country income group. Drop out was more likely early in treatment, particularly after the second visit.

Drop out needs to be reduced to ensure effective treatment.

Associations between specific parent and offspring mental disorders are likely to have been overestimated in studies that have failed to control for parent comorbidity.

To examine the associations of parent with respondent disorders.

Data come from the World Health Organization (WHO) World Mental Health Surveys (n = 51 507). Respondent disorders were assessed with the Composite International Diagnostic Interview and parent disorders with informant-based Family History Research Diagnostic Criteria interviews.

Although virtually all parent disorders examined (major depressive, generalised anxiety, panic, substance and antisocial behaviour disorders and suicidality) were significantly associated with offspring disorders in multivariate analyses, little specificity was found. Comorbid parent disorders had significant sub-additive associations with offspring disorders. Population-attributable risk proportions for parent disorders were 12.4% across all offspring disorders, generally higher in high- and upper-middle- than low-/lower-middle-income countries, and consistently higher for behaviour (11.0–19.9%) than other (7.1–14.0%) disorders.

Parent psychopathology is a robust non-specific predictor associated with a substantial proportion of offspring disorders.