It is unclear how many children and adolescents develop post-traumatic stress disorder (PTSD) after trauma.

To determine the incidence of PTSD in trauma-exposed children and adolescents as assessed with well-established diagnostic interviews and to examine potential moderators of the estimate.

A systematic literature search identified 72 peer-reviewed articles on 43 independent samples (n = 3563). Samples consisting only of participants seeking or receiving mental health treatment were excluded. Main analyses involved pooled incidence estimates and meta-analyses of variance.

The overall rate of PTSD was 15.9% (95% CI 11.5–21.5), which varied according to the type of trauma and gender. Least at risk were boys exposed to non-interpersonal trauma (8.4%, 95% CI 4.7–14.5), whereas girls exposed to interpersonal trauma showed the highest rate (32.9%, 95% CI 19.8–49.3). No significant difference was found for the choice of assessment interview or the informant of the assessment.

Research conducted with the best available assessment instruments shows that a significant minority of children and adolescents develop PTSD after trauma exposure, with those exposed to interpersonal trauma and girls at particular risk. The estimates provide a benchmark for DSM-5 and ICD-11.

The popular belief that creativity is associated with madness has increasingly become the focus of research for many psychologists and psychiatrists. However, despite being prime examples of creative thinking, comedy and humour have been largely neglected.

To test the hypothesis that comedians would resemble other creative individuals in showing a higher level of psychotic characteristics related to both schizophrenia and manic depression.

A group of comedians (n=500+) and a control sample of actors (n = 350+) completed an online questionnaire containing the short version of the Oxford–Liverpool Inventory of Feelings and Experiences (O-LIFE), with scales measuring four dimensions of psychotic traits. Scores were compared with general population norms.

Comedians scored significantly above O-LIFE norms on all four scales. Actors also differed from the norms but on only three of the scales. Most striking was the comedians' high score on both introverted anhedonia and extraverted impulsiveness.

This unusual personality structure may help to explain the facility for comedic performance.

There is robust evidence that childhood adversity is associated with an increased risk of psychosis. There is, however, little research on intervening factors that might increase or decrease risk following childhood adversity.

To investigate main effects of, and synergy between, childhood abuse and life events and cannabis use on odds of psychotic experiences.

Data on psychotic experiences and childhood abuse, life events and cannabis use were collected from 1680 individuals as part of the South East London Community Health Study (SELCoH), a population-based household survey.

There was strong evidence that childhood abuse and number of life events combined synergistically to increase odds of psychotic experiences beyond the effects of each individually. There was similar, but weaker, evidence for cannabis use (past year).

Our findings are consistent with the hypothesis that childhood abuse creates an enduring vulnerability to psychosis that is realised in the event of exposure to further stressors and risk factors.

Psychological stress is implicated in the development of schizophrenia, but little is known about experiences of stress among children at elevated risk for the disorder.

To examine stressor exposure and reactivity in children with different vulnerability profiles for schizophrenia: (a) children presenting multiple antecedents of schizophrenia (ASz group), (b) children with a family history of schizophrenia (FHx group) and (c) typically developing low-risk (TD) children.

Ninety-five children (ASz = 29; FHx = 19; ASz+FHx = 5; TD = 42), identified aged 9–12 years using a community-based screening procedure or as relatives of individuals with schizophrenia, completed questionnaires assessing environmental stressors and psychopathology at age 11–14 years.

Relative to their typically developing peers, children in the FHx and ASz groups were exposed to a greater number of negative life events and a higher frequency of daily stressors, respectively; and were more distressed by these experiences.

Stress exposure and reactivity may constitute useful targets of early intervention for psychosis.

Although youths in many countries have been exposed to terrorism, few studies have examined early risk and protective factors for the subsequent development of mental health problems.

To investigate the levels of post-traumatic stress in survivors of the 2011 massacre on Ut⊘ya Island compared with the general population in Norway, and to identify predictive factors.

Four hundred and ninety survivors were invited to participate. Structured face-to-face interviews were performed 4–5 months after the attack.

There were 325 study participants (response rate 66%). Survivors had been highly exposed to danger and loss. Post-traumatic stress levels were more than six times higher in survivors than in the general population. Predictors were female gender, minority ethnic status, high level of trauma exposure, pain, the loss of someone close and social support.

Survivor characteristics that can be assessed in the early aftermath of a terrorist attack strongly predict the subsequent mental health problems of exposed youths. The highly elevated symptoms observed were largely attributable to the traumatic experience and reflect the mental health costs of the terrorist attack.

Violence towards others in the community has been identified as a significant problem for a subset of Iraq and Afghanistan veterans.

To investigate the extent to which post-traumatic stress disorder (PTSD) and other risk factors predict future violent behaviour in military veterans.

A national, multiwave survey enrolling a random sample of all US veterans who served in the military after 11 September 2001 was conducted. A total of 1090 veterans from 50 US states and all military branches completed two survey waves mailed 1 year apart (retention rate = 79%).

Overall, 9% endorsed engaging in severe violence and 26% in other physical aggression in the previous year, as measured at Wave 2. Younger age, financial instability, history of violence before military service, higher combat exposure, PTSD, and alcohol misuse at Wave 1 were significantly associated with higher severe violence and other physical aggression in the past year at Wave 2. When combinations of these risk factors were present, predicted probability of violence in veterans rose sharply. Veterans with both PTSD and alcohol misuse had a substantially higher rate of subsequent severe violence (35.9%) compared with veterans with alcohol misuse without PTSD (10.6%), PTSD without alcohol misuse (10.0%) or neither PTSD nor alcohol misuse (5.3%). Using multiple regression, we found that veterans with PTSD and without alcohol misuse were not at significantly higher risk of severe violence than veterans with neither PTSD nor alcohol misuse. There was a trend for other physical aggression to be higher in veterans with PTSD without alcohol misuse.

Co-occurring PTSD and alcohol misuse was associated with a marked increase in violence and aggression in veterans. Compared with veterans with neither PTSD nor alcohol misuse, veterans with PTSD and no alcohol misuse were not significantly more likely to be severely violent and were only marginally more likely to engage in other physical aggression. Attention to cumulative effects of multiple risk factors beyond diagnosis – including demographics, violence history, combat exposure, and veterans' having money to cover basic needs like food, shelter, transportation, and medical care – is crucial for optimising violence risk management.

Repeat self-harm is an important risk factor for suicide. Few studies have explored risk factors for non-fatal repeat self-harm in Asia.

To investigate the risk of non-fatal repeat self-harm in a large cohort of patients presenting to hospital in Taipei City, Taiwan.

Prospective cohort study of 7601 patients with self-harm presenting to emergency departments (January 2004–December 2006). Survival analysis was used to examine the rates, timing and factors associated with repeat self-harm.

In total 778 (10.2%) patients presented to hospital with one or more further episodes of self-harm. The cumulative risk of non-fatal repetition within 1 year of a self-harm episode was 9.3% (95% CI 8.7–10.1). The median time to repetition within 1 year was 105 days. Females had a higher incidence of repeat self-harm than males (adjusted hazard ratio 1.25, 95% CI 1.05–1.48) but males had shorter median time to repetition (107 v. 80 days). Other independent risk factors for repeat self-harm within 1 year of an index episode were: young age, self-harm by medicine overdose and increasing number of repeat episodes of self-harm.

The risk of non-fatal repeat self-harm in Taipei City is lower than that seen in the West. Risk factors for repeat non-fatal self-harm differ from those for fatal self-harm. The first 3 months after self-harm is a crucial period for intervention.

Rates of self-harm are high and have recently increased. This trend and the repetitive nature of self-harm pose a significant challenge to mental health services.

To determine the efficacy of a structured group problem-solving skills training (PST) programme as an intervention approach for self-harm in addition to treatment as usual (TAU) as offered by mental health services.

A total of 433 participants (aged 18–64 years) were randomly assigned to TAU plus PST or TAU alone. Assessments were carried out at baseline and at 6-week and 6-month follow-up and repeated hospital-treated self-harm was ascertained at 12-month follow-up.

The treatment groups did not differ in rates of repeated self-harm at 6-week, 6-month and 12-month follow-up. Both treatment groups showed significant improvements in psychological and social functioning at follow-up. Only one measure (needing and receiving practical help from those closest to them) showed a positive treatment effect at 6-week (P = 0.004) and 6-month (P = 0.01) follow-up. Repetition was not associated with waiting time in the PST group.

This brief intervention for self-harm is no more effective than treatment as usual. Further work is required to establish whether a modified, more intensive programme delivered sooner after the index episode would be effective.

Facing frequent stigma and discrimination, many people with mental illness have to choose between secrecy and disclosure in different settings. Coming Out Proud (COP), a 3-week peer-led group intervention, offers support in this domain in order to reduce stigma's negative impact.

To examine COP's efficacy to reduce negative stigma-related outcomes and to promote adaptive coping styles (Current Controlled Trials number: ISRCTN43516734).

In a pilot randomised controlled trial, 100 participants with mental illness were assigned to COP or a treatment-as-usual control condition. Outcomes included self-stigma, empowerment, stigma stress, secrecy and perceived benefits of disclosure.

Intention-to-treat analyses found no effect of COP on self-stigma or empowerment, but positive effects on stigma stress, disclosure-related distress, secrecy and perceived benefits of disclosure. Some effects diminished during the 3-week follow-up period.

Coming Out Proud has immediate positive effects on disclosure- and stigma stress-related variables and may thus alleviate stigma's negative impact.