The first step to addressing persistent aggression in patients with schizophrenia spectrum disorders is to categorize the nature of the aggression to help inform the approach to treatment strategies . There is evidence that understanding violence as a dimension of psychiatric illness, by identifying the underlying etiology, is an effective approach to treatment [2–4]. Based on studies within the New York and California State Hospital Systems [2, 3], three categories of aggression can be utilized to help focus treatment: psychotic, impulsive and predatory (also called organized or instrumental).
Psychotic aggression derives from the positive symptoms of schizophrenia such as command hallucinations or persecutory delusional beliefs about a threat of harm from the victim. This type of aggression often appears to be unprovoked and some evidence indicates that it is the least common type of aggression in inpatient settings but also the most treatable.
Impulsive aggression is thought to be the most common form of inpatient aggression and is usually provoked in reaction to undesirable external stimuli, e.g. intrusive or threatening peer, denial of privilege by staff, etc. It occurs without due consideration of the consequences of the behavior and is often associated with an aroused emotional state, e.g. excited, angry or agitated .
Predatory aggression is planned, goal-oriented behavior not obviously related to threat or provocation that is often driven by retaliation and intimidation. These instrumental aggressors often present with little autonomic arousal. Predatory aggression is the second most common type of aggression and the least amenable to psychopharmacological interventions.