Severe Mental Illness and Aggressive Behavior: On the Importance of Considering Subgroups

Abstract

A minority of persons with severe mental illness (SMI) engage in violence towards others. These individuals, however, constitute a heterogeneous population with respect to patterns and correlates of violence. The present study used multivariate profile analyses to identify clusters of patients with SMI who displayed similar patterns of violence and similar correlates among 178 participants with SMI and a history of interpersonal violence. The types, locations, methods, and victims of violence, the associations of psychotic symptoms, alcohol and drug intoxication with violence, psychopathy traits, and impulsivity were entered into multiple correspondence analyses. Three subgroups of violent individuals were identified: psychotic, repetitive, and institutional. A fourth, unexpected subgroup of less violent persons was also found. The subgroups differed as to frequency, type, method, and location of violent incidents towards others; the presence of delusions, hallucinations, and intoxication when violent; and levels of psychopathy traits and impulsivity. These results demonstrate that among persons with SMI and considered at risk for violence, there are subgroups who display distinctive patterns and correlates of violent behavior. The finding that factors promoting violence in the subgroups differ indicates the need for distinct treatment and management strategies to reduce violence in each type.