Studies on adults have suggested important effects of stressful life events in provoking onset of psychiatric disorder. Only a few comparable studies on children exist, and their results are inconsistent in relation to definite timing effects. Meeting some important methodological challenges overlooked in the past research, this study set out to examine whether the onset of psychiatric disorder in children was more likely to occur shortly after a severe event, as compared with other times. The sample consisted of 99 consecutive, newly referred patients, aged 8–16 years, from a child psychiatry service in London. PACE (Psychosocial Assessment of Childhood Experiences), an investigator-based, standardized interview was used to assess the timing and impact of life events over the preceding 18 months. CAPA (Child and Adolescent Psychiatric Assessment), a standardized diagnostic assessment, was used to establish the presence, timing, and consequential impairment of child and adolescent psychiatric symptoms. In a within-subject, over-time design, conditional logistic regression techniques were employed to examine whether risk of onset was greater in the 9 weeks following a high-threat life event than at other times. There was a small but statistically significant association between child-reported events and child-reported onset; the associations with parent-reported onset were inconsistent. Parent-reported events failed to relate to onset by either source. The study offers only quite limited support to the notion of negative life events provoking onset of psychiatric disorder in children and young people. The possible reasons for this are discussed, together with important conceptual and methodological issues to problems of defining onset, and the choice of appropriate designs for data analysis.

The Strengths and Difficulties Questionnaire (SDQ) is a brief behavioural screening questionnaire that asks about children's and teenagers' symptoms and positive attributes; the extended version also includes an impact supplement that asks if the respondent thinks the young person has a problem, and if so, enquires further about chronicity, distress, social impairment, and burden for others. Closely similar versions are completed by parents, teachers, and young people aged 11 or more. The validation study involved two groups of 5–15-year-olds: a community sample (N=467) and a psychiatric clinic sample (N=232). The two groups had markedly different distributions on the measures of perceived difficulties, impact (distress plus social impairment), and burden. Impact scores were better than symptom scores at discriminating between the community and clinic samples; discrimination based on the single “Is there a problem?” item was almost as good. The SDQ burden rating correlated well (r=.74) with a standardised interview rating of burden. For clinicians and researchers with an interest in psychiatric caseness and the determinants of service use, the impact supplement of the extended SDQ appears to provide useful additional information without taking up much more of respondents' time.