Predispositions to violence in patients with schizophrenia are best explored within the context of violent behavior in the general population and can be characterized by trait aggressiveness, psychopathy, and impulsivity, according to a study published in Schizophrenia Research. A history of early conduct problems had a significant effect on the manifestation of these traits in schizophrenic and nonpsychotic violent populations.
This study sought to examine critical trait dispositions to violence, including psychopathic and impulsive behaviors and trait aggressiveness in patients with schizophrenia as well as in the general population. The researchers further sought to determine the extent that these traits predisposed individuals with schizophrenia to violence vs the role of other psychiatric symptoms in the etiology of violence and the impact of past conduct disturbances from childhood and adolescence.
The study sample included 144 participants: 40 violent patients with confirmed schizophrenia, 34 nonviolent patients with confirmed schizophrenia, 35 nonpsychotic violent individuals, and 35 nonviolent healthy controls. Trait predispositions were evaluated using the Psychopathy Checklist, Buss-Perry Aggression Questionnaire, and Barratt Impulsiveness Scale; additional analysis assessed psychiatric symptoms, drug and/or alcohol abuse, and past conduct problems. Primary inclusion criteria as a violent participant required a score above 15 in the Life History of Aggression Questionnaire and an occurrence of physical assault against another person within the past year.
Study results reported that the 2 violent groups showed more severe psychopathy, impulsivity, and trait aggressiveness the nonviolent groups. Violent participants were further divided into subgroups characterized with a history of early conduct problems or none. Analysis of the subgroup profiles allowed researchers to distinguish behaviors that could be attributed as predisposed traits or as symptoms of the schizophrenia illness. Risk factors most associated with predisposed traits included anger, motor impulsiveness, and self-control problems; according to the study data, trait severity was highest in the nonpsychotic violent group, followed by violent schizophrenia with a history of conduct problems. In the violent schizophrenia group with no past conduct problems, psychiatric symptoms associated with schizophrenia had a greater influence on violent behavior. In addition, this group had the greatest occurrence of substance abuse or dependence in association with violent behavior.
A study limitation was the generalizability to other populations: Study participants gave permission to access criminal records, meaning other, potentially more hostile or psychopathic individuals may have declined participation. Also, participants with schizophrenia were all chronic patients and did not include acute schizophrenia.
Patients with violent schizophrenia and a history of conduct problems had profiles most similar to nonpsychotic violent participants, suggesting certain traits predisposing individuals to violence underlie early conduct problems that continue into adulthood. The study authors found that aside from traits predisposing violence, psychiatric symptoms also influenced the emergence of violent behavior, including mood disorders and excitation.
Krakowski MI, Czobor P. Distinctive profiles of traits predisposing to violence in schizophrenia and in the general population [published online July 16, 2018]. Schizophrenia Res. doi: 10.1016/j.schres.2018.07.008