Violent behavior is a common reason for admission to inpatient psychiatric units, and may complicate treatment after admission. Substance abuse combined with other psychiatric conditions is an important risk factor for violent behavior. Other potential risk factors include paranoid delusions or hallucinations, impulsivity, personality disorder, and chaotic treatment environment.

The first step in assessing risk is ruling out medical illness that may give rise to violent behavior. Accordingly, a thorough history is critical, particularly for first-admission patients. In addition, a comprehensive interview may establish that the behavior is part of an ongoing pattern that in some areas can be corroborated by police records.

Akathisia and other drug effects are another risk factor for violent behavior. Dr. Citrome stated, however, that akathisia-related violent behavior may become less frequent with increasing use of atypical antipsychotics, which are less likely to induce akathisia or other extrapyramidal adverse effects.

Dr. Citrome identified two types of aggressive behavior with different clinical ramifications. The treatment for a single violent episode differs from that for a violent episode in a patient with a history of violent episodes. Because transient factors often trigger isolated violent episodes, removing patients from exposure to those factors may be effective. Patients with sporadic violent behavior often respond well to atypical antipsychotics. In contrast, patients with habitually violent behavior often do not respond to atypical antipsychotics and may remain violent throughout hospitalization.

Treatment includes many considerations, according to Dr. Citrome. Limit setting and general behavior-oriented treatments are important, as is change in environment. Use of restraints or locking patients in their rooms may reduce stimulation and help produce calm. Medications such as lorazepam may be effective, although sedation and potential for abuse limit their use to acute treatment.

Persistently aggressive patients often need special units. Ambulatory restraints are also useful when allowed. Medicines include atypical antipsychotics and mood stabilizers, such as valproate. Typical antipsychotic medication may cause additional problems in this group, however. While high doses may afford helpful sedation, they can also induce akathisia. Moreover, they may increase risk of seizures in patients with some substance withdrawal syndromes.

Atypical medications are important in the general treatment of schizophrenia. Injectable formulations appear to be a helpful addition to treatment and may offer advantages, such as low risk of extrapyramidal adverse effects and ease of transition to oral formulations.

Dr. Citrome said that controlling violence and maintaining patients' level of function are the goals of long-term treatment. Atypical antipsychotics, particularly clozapine, have been used successfully in long-term treatment of violent patients. Data from clinical trials with risperidone indicate that it, too, may have specific anti-agressive effects.