A systematic review and meta-analysis on adverse childhood experiences: Prevalence in youth offenders and their effects on youth recidivism.

BACKGROUND: Adverse childhood experiences (ACEs) have been found to be more prevalent among youth involved with the criminal justice system compared to their counterparts in the general population. The present study aims to systematically review the existing empirical studies to provide a comprehensive understanding of the prevalence of ACEs among youth offenders aged between 10 and 19 years, and the effects of both cumulative ACEs and individual ACE items on youth recidivism. METHOD: A systematic review approach was employed. Narrative synthesis and meta-analysis were performed to synthesise the data in 31 included studies. RESULTS: The pooled prevalence of cumulative ACEs was 39.4 %. The pooled prevalence of individual ACEs ranged between 13.7 % to 51.4 %. Cumulative ACEs and neglect were positively associated with youth recidivism, with OR = 1.966, 95%CI [1.582, 2.444] and OR = 1.328, 95%CI [1.078, 1.637], respectively. Physical and sexual abuse were not significantly associated with youth recidivism. Regarding the mechanisms underlying the relationship between ACEs and recidivism; moderators included gender, positive childhood experiences, strong social bonds, and empathy. Mediators included child welfare placement, emotional and behavioural problems, drug use, mental health problems, and negative emotionality. CONCLUSION: Developing programs to youth offenders aiming to address the impact of cumulative and individual ACE exposure, strengthen the protective factors and weaken the risk factors would be useful to reduce youth recidivism.

The role of serotonin in nonnormative risky choice: the effects of tryptophan supplements on the "reflection effect" in healthy adult volunteers.

Risky decision-making involves weighing good and bad outcomes against their probabilities in order to determine the relative values of candidate actions. Although human decision-making sometimes conforms to rational models of how this weighting is achieved, irrational (or nonnormative) patterns of risky choice, including shifts between risk-averse and risk-seeking choices involving equivalent-value gambles (the "reflection effect"), are frequently observed. In the present experiment, we investigated the role of serotonin in decision-making under conditions of uncertainty. Fifteen healthy adult volunteers received a treatment of 3 g per day of the serotonin precursor, tryptophan, in the form of dietary supplements over a 14-day period, whereas 15 age- and IQ-matched control volunteers received a matched placebo substance. At test, all participants completed a risky decision-making task involving a series of choices between two simultaneously presented gambles, differing in the magnitude of their possible gains, the magnitude of their possible losses, and the probabilities with which these outcomes were delivered. Tryptophan supplements were associated with alterations in the weighting of gains and small losses perhaps reflecting reduced loss-aversion, and a marked and significant diminution of the reflection effect. We conclude that serotonin activity plays a significant role in nonnormative risky decision-making under conditions of uncertainty.