Increased post-traumatic stress disorder (PTSD) rates have been documented in children exposed to war. However, the contribution of childhood adversities and environmental sensitivity to children's responses to adversities and trauma are still far from settled.

To evaluate the relative roles of war, childhood adversities and sensitivity in the genesis of PTSD.

Data on childhood adversities and sensitivity was collected from 549 Syrian refugee children in Lebanon. PTSD symptoms were assessed using the PTSD Reaction Index.

Although childhood adversities, war events and sensitivity were all significantly related to PTSD in bivariate analyses, multivariate analyses showed that childhood adversities were the most important variable in predicting PTSD. The effect of war on PTSD was found to be dependent on the interplay between childhood adversities and sensitivity, and was most prominent in highly sensitive children with lower levels of adversities; in sensitive children experiencing high levels of adversities, the effects of war exposure on PTSD were less pronounced.

When considering the effects of war on PTSD in refugee children, it is important to take account of the presence of other adversities as well as of children's sensitivity. Sensitive children may be more vulnerable to the negative effects of war exposure, but only in contexts that are characterised by low childhood adversities.

None.

Traumatic events are associated with increased risk of psychotic experiences, but it is unclear whether this association is explained by mental disorders prior to psychotic experience onset.

To investigate the associations between traumatic events and subsequent psychotic experience onset after adjusting for post-traumatic stress disorder and other mental disorders.

We assessed 29 traumatic event types and psychotic experiences from the World Mental Health surveys and examined the associations of traumatic events with subsequent psychotic experience onset with and without adjustments for mental disorders.

Respondents with any traumatic events had three times the odds of other respondents of subsequently developing psychotic experiences (OR=3.1, 95% CI 2.7–3.7), with variability in strength of association across traumatic event types. These associations persisted after adjustment for mental disorders.

Exposure to traumatic events predicts subsequent onset of psychotic experiences even after adjusting for comorbid mental disorders.

Although significant associations of childhood adversities with adult mental disorders are widely documented, most studies focus on single childhood adversities predicting single disorders.

To examine joint associations of 12 childhood adversities with first onset of 20 DSM–IV disorders in World Mental Health (WMH) Surveys in 21 countries.

Nationally or regionally representative surveys of 51 945 adults assessed childhood adversities and lifetime DSM–IV disorders with the WHO Composite International Diagnostic Interview (CIDI).

Childhood adversities were highly prevalent and interrelated. Childhood adversities associated with maladaptive family functioning (e.g. parental mental illness, child abuse, neglect) were the strongest predictors of disorders. Co-occurring childhood adversities associated with maladaptive family functioning had significant subadditive predictive associations and little specificity across disorders. Childhood adversities account for 29.8% of all disorders across countries.

Childhood adversities have strong associations with all classes of disorders at all life-course stages in all groups of WMH countries. Long-term associations imply the existence of as-yet undetermined mediators.

Little is known about the epidemiology of adult attention-deficit hyperactivity disorder (ADHD).

To estimate the prevalence and correlates of DSM-IV adult ADHD in the World Health Organization World Mental Health Survey Initiative.

An ADHD screen was administered to respondents aged 18–44 years in ten countries in the Americas, Europe and the Middle East (n=11422). Masked clinical reappraisal interviews were administered to 154 US respondents to calibrate the screen. Multiple imputation was used to estimate prevalence and correlates based on the assumption of cross-national calibration comparability.

Estimates of ADHD prevalence averaged 3.4% (range 1.2–7.3%), with lower prevalence in lower-income countries (1.9%) compared with higher-income countries (4.2%). Adult ADHD often co-occurs with other DSM-IV disorders and is associated with considerable role disability. Few cases are treated for ADHD, but in many cases treatment is given for comorbid disorders.

Adult ADHD should be considered more seriously in future epidemiological and clinical studies than is currently the case.