This study was designed to examine whether proactive and reactive aggression are meaningful distinctions at the variable-and person-based level, and to determine their associated behavioral profiles. Data from 587 adolescents (mean age 15.6; 71.6 % male) from clinical samples of four different sites with differing levels of aggression problems were analyzed. A multi-level Latent Class Analysis (LCA) was conducted to identify classes of individuals (personbased) with similar aggression profiles based on factor scores (variable-based) of the Reactive Proactive Questionnaire (RPQ) scored by self-report. Associations were examined between aggression factors and classes, and externalizing and internalizing problem behavior scales by parent report (CBCL) and self-report (YSR). Factor-analyses yielded a three factor solution: 1) proactive aggression, 2) reactive aggression due to internal frustration, and 3) reactive aggression due to external provocation. All three factors showed moderate to high correlations. Four classes were detected that mainly differed quantitatively (no 'proactive-only' class present), yet also qualitatively when age was taken into account, with reactive aggression becoming more severe with age in the highest affected class yet diminishing with age in the other classes. Findings were robust across the four samples. Multiple regression analyses showed that 'reactive aggression due to internal frustration' was the strongest predictor of YSR and CBCL internalizing problems. However, results showed moderate to high overlap between all three factors. Aggressive behavior can be distinguished psychometrically into three factors in a clinical sample, with some differential associations. However, the clinical relevance of these findings is challenged by the person-based analysis showing proactive and reactive aggression are mainly driven by aggression severity.

The Reactive Proactive Questionnaire (RPQ) was originally developed to assess reactive and proactive aggressive behavior in children. Nevertheless, some studies have used the RPQ in adults. This study examines the reliability of the RPQ within an adult sample by investigating whether reactive and proactive aggression can be distinguished at a variable-and person-based level. Male adults from forensic samples (N ¼ 237) and from the general population (N ¼ 278) completed the RPQ questionnaire. Variable-based approaches, including factor analyses, were conducted to verify the two-factor model of the RPQ and to examine alternative factor solutions of the 23 items. Subsequently, a person-based approach, i.e., Latent Class Analysis (LCA), was executed to identify homogeneous classes of subjects with similar profiles of aggression in the observed data. The RPQ proved to have sufficient internal consistency. Multiple-factor models were examined, but the original two-factor model was statistically and theoretically considered as most solid and in line with previous research. The multi-level LCA identified three different classes of aggression severity (class 1 showed low aggressive behavior; class 2 subjects displayed modest aggression levels; and class 3 exhibited the highest level of aggressive behavior). In addition, class 1 and 2 showed more reactive than proactive aggression, whereas class 3 displayed comparable levels of reactive/proactive aggression. The RPQ appears to have clinical relevance for adult populations in the way that it can distinguish severity levels of aggression. Before the RPQ is implemented in adult populations, norm scores need to be developed. Aggr. Behav. 43:155-162, 2017.

Conduct disorder (CD) is a frequently occurring psychiatric disorder characterized by a persistent pattern of aggressive and non-aggressive rule breaking antisocial behaviours that lead to considerable burden for the patients themselves, their family and society. This review paper updates diagnostic and therapeutic approaches to CD in the light of the forthcoming DSM-5 definition. The diagnostic criteria for CD will remain unchanged in DSM-5, but the introduction of a specifier of CD with a callous-unemotional (CU) presentation is new. Linked to this, we discuss the pros and cons of various other ways to subtype aggression/CD symptoms. Existing guidelines for CD are, with few exceptions, already of a relatively older date and emphasize that clinical assessment should be systematic and comprehensive and based on a multi-informant approach. Non-medical psychosocial interventions are recommended as the first option for the treatment of CD. There is a role for medication in the treatment of comorbid syndromes and/or in case of insufficient response to psychosocial interventions and severe and dangerous aggressive and violent behaviours.

Maladaptive aggression in adolescents is an increasing public health concern. Cognitive Behavior Therapy (CBT) is one of the most common and promising treatments of aggression. However, there is a lack of information on predictors of treatment response regarding CBT. Therefore, a meta-analysis was performed examining the role of predictors on treatment response of CBT. Twenty-five studies were evaluated (including 2,302 participants; 1,580 boys and 722 girls), and retrieved through searches on PubMed, PsycINFO and EMBASE. Effect sizes were calculated for studies that met inclusion criteria. Study population differences and specific CBT characteristics were examined for their explanatory power. There was substantial variation across studies in design and outcome variables. The meta-analysis showed a medium treatment effect for CBT to reduce aggression (Cohen'd = 0.50). No predictors of treatment response were found in the meta-analysis. Only two studies did examine whether proactive versus reactive aggression could be a moderator of treatment outcome, and no effect was found of this subtyping of aggression. These study results suggest that CBT is effective in reducing maladaptive aggression. Furthermore, treatment setting and duration did not seem to influence treatment effect, which shows the need for development of more cost-effective and less-invasive interventions. More research is needed on moderators of outcome of CBT, including proactive versus reactive aggression. This requires better standardization of design, predictors, and outcome measures across studies.