A meta-analysis of positive psychology intervention (PPIs) studies was conducted. PPIs were defined as interventions in which the goal of wellbeing enhancement was achieved through pathways consistent with positive psychology theory. Data were extracted from 347 studies involving over 72,000 participants from clinical and non-clinical child and adult populations in 41 countries. The effect of PPIs with an average of ten sessions over six weeks offered in multiple formats and contexts was evaluated. At post-test, PPIs had a significant small to medium effect on wellbeing (g = 0.39), strengths (g = 0.46), QoL (g = 0.48), depression (g = −0.39), anxiety (g = −0.62), and stress (g = −0.58). Gains were maintained at three months follow-up. Individuals in non-western countries with clinical problems, who engaged in longer individual or group therapy programs containing multiple PPIs benefited most. This meta-analysis shows that PPIs have an extensive evidence base supporting their effectiveness.

Childhood maltreatment has diverse, lifelong impact on morbidity and mortality. The Childhood Trauma Questionnaire (CTQ) is one of the most commonly used scales to assess and quantify these experiences and their impact. Curiously, despite very widespread use of the CTQ, scores on its Minimization-Denial (MD) subscale—originally designed to assess a positive response bias—are rarely reported. Hence, little is known about this measure. If response biases are either common or consequential, current practices of ignoring the MD scale deserve revision. Therewith, we designed a study to investigate 3 aspects of minimization, as defined by the CTQ’s MD scale: 1) its prevalence; 2) its latent structure; and finally 3) whether minimization moderates the CTQ’s discriminative validity in terms of distinguishing between psychiatric patients and community volunteers. Archival, item-level CTQ data from 24 multinational samples were combined for a total of 19,652 participants. Analyses indicated: 1) minimization is common; 2) minimization functions as a continuous construct; and 3) high MD scores attenuate the ability of the CTQ to distinguish between psychiatric patients and community volunteers. Overall, results suggest that a minimizing response bias—as detected by the MD subscale—has a small but significant moderating effect on the CTQ’s discriminative validity. Results also may suggest that some prior analyses of maltreatment rates or the effects of early maltreatment that have used the CTQ may have underestimated its incidence and impact. We caution researchers and clinicians about the widespread practice of using the CTQ without the MD or collecting MD data but failing to assess and control for its effects on outcomes or dependent variables.

The aim of the systematic review described in this article was to synthesize available high-quality evidence on the outcomes of noninstitutional child maltreatment across the life span. A systematic review of previous systematic reviews and meta-analyses was conducted. Ten databases were searched. One hundred eleven papers which met stringent inclusion and exclusion criteria were selected for review. Papers were included if they reported systematic reviews and meta-analyses of longitudinal or cross-sectional controlled studies, or single-group cohort primary studies of the outcomes of child maltreatment in the domains of physical and mental health and psychosocial adjustment of individuals who were children lived mainly with their families. Using AMSTAR criteria, selected systematic reviews and meta-analyses were found to be of moderate or high quality. Searches, study selection, data extraction, and study quality assessments were independently conducted by two researchers, with a high degree of interrater reliability. The 111 systematic reviews and meta-analyses reviewed in this article covered 2,534 independent primary studies involving 30,375,962 participants, of whom more than 518,022 had been maltreated. The magnitude and quality of this evidence base allow considerable confidence to be placed in obtained results. Significant associations were found between a history of child maltreatment and adjustment in the domains of physical health, mental health, and psychosocial adjustment in a very wide range of areas. The many adverse outcomes associated with child maltreatment documented in this review highlight the importance of implementing evidence-based child protection policies and practices to prevent maltreatment and treat child abuse survivors.