Haloperidol for long-term aggression in psychosis


People experiencing distressing delusions and hallucinations can often become agitated and aggressive. The antipsychotic drug haloperidol is widely used for the treatment of schizophrenia and psychosis-induced agitation despite the possibility it can cause a number of serious side effects such as nausea, vomiting, dizziness, restlessness and muscle spasms.

Study characteristics

The Cochrane Schizophrenia Group ran an electronic search for clinical trials involving the use of haloperidol for psychosis-induced aggression in July 2011 and April 2015. We found one study with 110 participants, diagnosed with schizophrenia or schizoaffective disorder. Participants had been physically aggressive during recent hospitalisation and involved in at least one other aggressive event. The study randomised participants to receive either haloperidol, clozapine or olanzapine.

Key results

Most data presented were impossible to use and it is unclear if haloperidol is effective for reducing aggression or improving mental state for people who are aggressive due to psychosis. There were no data regarding side effects. The number of people leaving the study early from each treatment group was similar.

Quality of evidence

The quality of evidence available is low, only one study with a high risk of selective reporting of results provided data. No firm conclusions can be made until further good-quality data are available.

Authors' conclusions: 

Only one study could be included and most data were heavily skewed, almost impossible to interpret and of low quality. There were also some limitations in the study design with unclear description of allocation concealment and high risk of bias for selective reporting, so no firm conclusions can be made. This review shows how trials in this group of people are possible - albeit difficult. Further relevant trials are needed to evaluate use of haloperidol in treatment of long-term/persistent aggression in people living with psychosis.

Read the full abstract...

Psychotic disorders can lead some people to become agitated. Characterised by restlessness, excitability and irritability, this can result in verbal and physically aggressive behaviour - and both can be prolonged. Aggression within the psychiatric setting imposes a significant challenge to clinicians and risk to service users; it is a frequent cause for admission to inpatient facilities. If people continue to be aggressive it can lengthen hospitalisation. Haloperidol is used to treat people with long-term aggression.


To examine whether haloperidol alone, administered orally, intramuscularly or intravenously, is an effective treatment for long-term/persistent aggression in psychosis.

Search strategy: 

We searched the Cochrane Schizophrenia Group Trials Register (July 2011 and April 2015).

Selection criteria: 

We included randomised controlled trials (RCT) or double blind trials (implying randomisation) with useable data comparing haloperidol with another drug or placebo for people with psychosis and long-term/persistent aggression.

Data collection and analysis: 

One review author (AK) extracted data. For dichotomous data, one review author (AK) calculated risk ratios (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis based on a fixed-effect model. One review author (AK) assessed risk of bias for included studies and created a 'Summary of findings' table using GRADE.

Main results: 

We have no good-quality evidence of the absolute effectiveness of haloperidol for people with long-term aggression. One study randomising 110 chronically aggressive people to three different antipsychotic drugs met the inclusion criteria. When haloperidol was compared with olanzapine or clozapine, skewed data (n=83) at high risk of bias suggested some advantage in terms of scale scores of unclear clinical meaning for olanzapine/clozapine for 'total aggression'. Data were available for only one other outcome, leaving the study early. When compared with other antipsychotic drugs, people allocated to haloperidol were no more likely to leave the study (1 RCT, n=110, RR 1.37, CI 0.84 to 2.24, low-quality evidence). Although there were some data for the outcomes listed above, there were no data on most of the binary outcomes and none on service outcomes (use of hospital/police), satisfaction with treatment, acceptance of treatment, quality of life or economics.