Evidence-Based Reviews

Evaluating psychotic patients' risk of violence: A practical guide

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Investigate persecutory delusions and command hallucinations



When evaluating a patient’s risk of violence, the presence of psychosis is a crucial concern. Douglas et al1 found that psychosis was the most important predictor of violent behavior in an analysis of 204 studies examining the relationship between psychopathology and aggression. Clinicians need to be familiar with aspects of persecutory delusions and command auditory hallucinations that are associated with an increased risk of aggression because accurately assessing patients who are experiencing these 2 symptoms is an important part of a comprehensive violence risk assessment.

This article highlights the importance of investigating persecutory delusions and command auditory hallucinations when evaluating a psychotic patient’s risk for violence. We provide specific questions to ask to help gauge risk associated with these 2 symptoms.

Evaluating persecutory delusions

Do persecutory delusions increase the risk that a person will behave violently? Research examining delusions’ contribution to violent behavior does not provide a clear answer. Earlier studies suggested that persecutory delusions were associated with an increased risk of aggression.2 Delusions noted to increase the risk of violence were characterized by threat/control-override (TCO) symptoms. TCO symptoms are beliefs that one is being threatened (eg, being followed or poisoned) or is losing control to an external source (eg, one’s mind is dominated by forces beyond his or her control).3 Similarly, using data from the Epidemiologic Catchment Area surveys, Swanson et al4 found that patients who reported TCO symptoms were approximately twice as likely to engage in assaultive behavior compared with patients with other psychotic symptoms.

In contrast, the MacArthur Study of Mental Disorder and Violence5,6 showed that the presence of delusions did not predict higher rates of violence among recently discharged psychiatric patients. In particular, researchers did not find a relationship between the presence of TCO delusions and violent behavior. In a study comparing male criminal offenders with schizophrenia found not guilty by reason of insanity with matched non-offending schizophrenia patients, Stompe et al7 found no significant association between TCO symptoms and severity of violent behavior; prevalence of TCO symptoms did not differ between the 2 groups. However, nondelusional suspiciousness—such as misperceiving others’ behavior as indicating hostile intent—was associated with subsequent violence.6

Nederlof et al8 conducted a cross-sectional multicenter study to further examine whether TCO symptoms are related to aggressive behavior. Their study included 124 patients (88% men) who had paranoid schizophrenia (70%), “other forms” of schizophrenia (16%), schizoaffective disorder (3%), delusional disorder (1%), and psychosis not otherwise specified (10%). To measure TCO symptoms in a more detailed manner than in previous research, these researchers developed the Threat/Control-Override Questionnaire (TCOQ), a 14-item, self-report scale. The 7 threat items specific to the TCOQ are:8

  • I am under the control of an external force that determines my actions.
  • Other people have tried to poison me or to do me harm.
  • Someone has deliberately tried to make me ill.
  • Other people have been secretly plotting to ruin me.
  • Someone has had evil intentions against me.
  • I have the thought that I was being followed for a special reason.
  • People have tried to drive me insane.

The 7 control-override items on the TCOQ are:8

  • Other people control my way of movements.
  • Other people can insert thoughts into my head.
  • My thoughts are dominated by an external force.
  • I have the feeling that other people can determine my thoughts.
  • Other people can insert thoughts into my mind.
  • I have the feeling that other people have control over me.
  • My life is being determined by something or someone except for myself.

Nederlof et al8 determined that TCO symptoms were a significant correlate of aggression in their study sample. When the 2 domains of TCO symptoms were evaluated separately, only threat symptoms made a significant contribution to aggressive behavior. These researchers suggested that varying methods of measuring TCO symptoms may underlie previous studies’ seemingly contradictory findings.8 These recent findings indicate that the debate regarding the contribution of TCO symptoms, particularly threat symptoms, to future violence remains active.

Appelbaum et al9 used the MacArthur-Maudsley Delusions Assessment Schedule to examine the contribution of non-content-related delusional material to violence in interviews with 328 delusional hospitalized psychiatric patients. The 7 dimensions of the MacArthur-Maudsley Delusions Assessment Schedule are:

  • Conviction—the degree of certainty about the delusional belief
  • Negative affect—whether the delusional belief makes the patient unhappy, frightened, anxious, or angry
  • Action—the extent to which the patient’s actions are motivated by the delusional belief
  • Inaction—whether the patient has refrained from any action as a result of the delusional belief
  • Preoccupation—the extent to which the patient indicates his or her thoughts focus exclusively on the delusion
  • Pervasiveness—the degree to which the delusional belief penetrates all aspects of the patient’s experiences
  • Fluidity—the degree to which the delusional belief changed frequently during the interview.


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