The key finding of this study is that peer victimization significantly mediates the relationship between schizotypal personality and aggression in children. This partial mediation effect was strong, accounting for 59% of the relationship. Mediation occurred in females as well as males, providing cross-gender independent replication of findings. Mediation applied to all 3 subfactors of schizotypy, and findings could not be accounted for by method bias. A second finding was that schizotypy was most strongly associated with reactive aggression; after controlling for this form of aggression, the schizotypy-proactive aggression relationship was nullified. Third, the 3-factor structure to the SPQ-C was confirmed. Findings are to the authors’ knowledge the first to document a mediator of the schizotypy-aggression relationship and also provide further evidence for the utility of the SPQ-C as a brief and simple measure of schizotypal personality in children. Findings have potential implications for the consideration of influences other than substance abuse as a cause of increased aggression in schizophrenia-spectrum disorders,3
including schizotypal symptomatology itself and consequent victimization.
The current findings support a model in which schizotypal traits elicit victimization from other children, which in retaliatory turn stimulates reactive aggression. This model is based on a very large sample and was tested using a statistical test of mediation (Sobel’s z
), which is viewed as very conservative.40
One question arising from this model concerns how the disorganized, interpersonal, and cognitive-perceptual features of schizotypy could give rise to peer victimization. Odd behavior and odd speech could result in a child being called names, while lack of close friends and blunted affect may result in a child drifting toward the periphery of social interactions and ultimately being socially excluded from games. Magical thinking could similarly result in a child being made fun of, while paranoid ideation and social anxiety could result in a child being kept at a social distance and ultimately ostracized. It is furthermore conceivable that relatively mild forms of victimization (in the forms of social exclusion and verbal abuse) could result in an exacerbation of some schizotypal features (eg, social anxiety, no close friends, paranoid ideation) which further precipitates escalating victimization, including attack on property and physical victimization. The schizotypy-victimization relationship may be less of a unidirectional relationship and more of an escalating viscous cycle between these 2 constructs that eventually propels the schizotypal child into reactive aggression, a form of aggression conceptualized as a fear-induced, irritable, and hostile affect-laden defensive response to provocation.41,42
A second question raised by the results concerns why schizotypy should be more related to reactive than proactive aggression. As illustrated in , reactive aggression was approximately 3 times more strongly related to schizotypy than was proactive aggression. Furthermore, the small positive proactive-schizotypy relationship was abolished after controlling for schizotypy and rendered slightly negative (ie, higher schizotypy-lower proactive aggression). To understand this selective relationship with reactive aggression, schizotypy is characterized by information-processing deficits.43
In turn, theoretical perspectives on reactive aggression have emphasized information processing deficits44,45
and the lack of regulatory control over behavior.45
Specifically, reactively aggressive children show deficits in the early encoding, processing, and interpretation stages of social information processing, resulting in a hostile attributional bias to incoming cues.44
Such social information-processing deficits could also give rise to more pervasive fundamental information-processing deficits, such as the symptoms of unusual perceptual experiences, ideas of reference, and paranoid ideation symptoms, which can also be viewed as errors in encoding social cues.10,23
Heightened and diffuse sensory awareness, loss of reality testing, ideational, and delusional thinking represent 4 core traits of reactive aggression,46
traits which also characterize individuals with schizotypal personality disorder. Social anxiety and paranoid ideation are schizotypal features that are consistent with the fact that reactively aggressive individuals are hypervigilant to stimuli that could be perceived as threatening.47,48
While the schizophrenia-violence relationship has been extensively researched, there is little or no research on whether the form of violence is reactive or proactive in nature. The present findings on schizotypy give rise to the hypothesis that violence in schizophrenia may in general be more likely to be reactive than proactive.
A second aim of the study was to further assess the utility of the SPQ-C. Its internal reliability at .82 is very similar to reliabilities of .80 and .83, previously reported,25
and to that of 0.81 reported by Seah and Ang.11
More importantly, even though this child instrument is brief (22 items) compared with the adult SPQ (74 items—Raine 1991), we were able to confirm the 3-factor structure originally obtained with longer adult instrument,23
demonstrating support for a downward extension of this adult structure of schizotypy into childhood. The confirmation of the hypothesized differential relationship with reactive but not proactive forms of aggression also provides initial evidence for construct validity, further supporting the construct and discriminant validity previously shown for this instrument.11,26
Construct validity is further provided by the current mediation findings. Because there has been a dearth of research on childhood schizotypy, the SPQ-C provides a promising self-report instrument to further investigate in children the correlates of the early manifestation of schizotypal personality and can be provided upon request to the first author.
It should be clarified that one cannot easily extend downwards from adult schizophrenia and violence to childhood schizotypy and aggression. The findings presented here parallel the adult literature but do not exactly model it. In addition, one meta-analysis has found while schizophrenia patients lacking comorbidity with substance abuse are at higher risk for violence (OR 2.1) and those with comorbidity for substance abuse show a higher risk for violence (OR 8.9), indicating the importance of adult substance abuse in moderating schizophrenia-violence relationships.2
Substance abuse cannot easily be held accountable for the link we document here between childhood schizotypy and aggression, particularly because the younger children (age 11 years and below) show if anything a stronger relationship between schizotypy and aggression than those aged 11–16 years where mild levels of substance abuse might be suspected (see online supplementary materials
). At least at this age, peer victimization would appear to be a more viable explanation of the schizotypy-aggression comorbidity although future studies need to consider other explanations of this relationship, including confounding variables.
Five limitations of this study should be acknowledged. First, only partial mediation was demonstrated. Clearly, peer victimization is only one of a number of social as well as neurobiological processes that may explain the schizotypy-aggression relationship. Second, the current findings pertain to individual differences in schizotypal personality and need to be extended to children with clinical manifestations of schizotypy. Third, this study focused on children and it remains to be seen if the same findings can be observed with adults. Fourth, while the establishment of the expected factor structure to the SPQ-C suggests some degree of cross-cultural generalizability, findings on victimization and aggression from this East Asian sample need to be generalized to Western samples. Fifth, although we statistically tested a mediating model that implies causality, true causality cannot be demonstrated without experimental manipulation; future prospective longitudinal research may however help better tease out the temporal ordering of variables used in this correlational study to further substantiate what must be treated as an initial model.
Set against these limitations are a number of strengths. To the authors’ knowledge, this is the first study to identify a mediator of the schizotypy-aggression relationship using a statistical mediational model. Although only a partial mediator, the effect was nevertheless substantial, explaining more than half of the schizotypy-aggression relationship. The fact that this mediator is a psychosocial process provides support for the relevance of social processes in understanding schizotypy and its relationship with aggression.7
The sample size was also very large, and replication was shown across independent samples (males and females). Findings were not found to be a function of method error. This study also offers a new, brief, instrument for self-report schizotypy for use in children and adolescents.
The mediation findings in turn have potential prevention implications. Victimization is a risk factor for aggression that is preventable.49
Recognition by mental health professionals that those with schizotypy and other schizophrenia-spectrum disorders may be subject to victimization which in turn could fuel retaliatory aggressive and violent behavior that could facilitate interventions which would be predicted to reduce the likelihood of reactive aggression and potentially ameliorate schizotypal symptomatology. The individual difference approach employed here with community children and adolescents provides a new model that provides an initial basis for substantiation and replication in future longitudinal clinical research on adults in Western cultures. Finally, better understanding and remediation of aggressive behavior in schizophrenia-spectrum patients may help reduce the stigma associated with this disorder.1,50