Abstract
Background
Chronic amphetamine users may have experience of paranoia and hallucination. It has long been believed that dopamine antagonists, such as chlorpromazine, haloperidol, and thioridazine, are effective for the treatment of amphetamine psychosis.
Objectives
To evaluate risks, benefits, costs of treatments for amphetamine psychosis.
Search methods
MEDLINE (1966-2007), EMBASE (1980-2007), CINAHL (1982-2007), PsychINFO (1806-2007), CENTRAL (Cochrane Library 2008 issue 1), references of obtained articles.
Selection criteria
All randomised controlled and clinical trials (RCTs, CCTs) evaluating treatments (alone or combined) for people with amphetamine psychosis
Data collection and analysis
Two authors evaluated and extracted the data independently. Dichotomous data were extracted on an intention-to-treat basis in which the dropouts were assigned as participants with the worst outcomes. The Relative Risk (RR) with the 95% confidence interval (95% CI) was used to assess the dichotomous data. The Weighted Mean Difference (WMD) with 95% CI was used to assess the continuous data.
Main results
The comprehensive searches found one randomised controlled trial of treatment for amphetamine psychosis meeting the criteria for considering studies. The study involved 58 participants and compared the efficacy and tolerability of two antipsychotic drugs, olanzapine (a newer antipsychotic) and haloperidol (a commonly used antipsychotic medication used as a control condition), in treating amphetamine-induced psychosis. The results show that both olanzapine and haloperidol at clinically relevant doses were efficacious in resolving psychotic symptoms, with the olanzapine condition showing significantly greater safety and tolerability than the haloperidol control as measured by frequency and severity of extrapyramidal symptoms.
Authors’ conclusions
Only one RCT of treatment for amphetamine psychosis has been published. Outcomes from this trial indicate that antipsychotic medications effectively reduce symptoms of amphetamine psychosis, the newer generation and more expensive antipsychotic medication, olanzapine, demonstrates significantly better tolerability than the more affordable and commonly used medication, haloperidol.
There are other two studies that did not meet the inclusion criteria for this review. The results of these two studies show that agitation and some psychotic symptoms may be abated within an hour after antipsychotic injection.
Whether this limited evidence can be applied for amphetamine psychotic patients is not yet known.
The medications that should be further investigate are conventional antipsychotics, newer antipsychotics and benzodiazepines. However, naturalistic studies of amphetamine psychotic symptoms and the prevalence of relapse to psychosis in the presence of amphetamine, are also crucial for advising the development of study designs appropriate for further treatment studies of amphetamine psychosis.
Plain language summary
Treatment for amphetamine psychosis
A minority of individuals who use amphetamines develop full-blown psychosis requiring care at emergency departments or psychiatric hospitals. In such cases, symptoms of amphetamine psychosis commonly include paranoid and persecutory delusions as well as auditory and visual hallucinations in the presence of extreme agitation. More common (about 18%) is for frequent amphetamine users to report psychotic symptoms that are sub-clinical and that do not require high-intensity intervention. Clinical reports suggest the development of amphetamine psychosis and of sub-clinical psychosis symptoms is related to the individual’s lifetime history of amphetamine use, i.e., cumulative quantity and frequency of exposure to amphetamines. In one of the only randomised trials of antipsychotic medications for treating amphetamine psychosis, Leelahanaj (2005) reported that olanzapine and haloperidol delivered at clinically relevant doses both showed similar efficacy in resolving psychotic symptoms (93% and 79%, respectively), with olanzapine showing significantly greater safety and tolerability than haloperidol as measured by frequency and severity of extrapyramidal symptoms. These outcomes are consistent with treatments for schizophrenia indicating equivalent efficacy between atypical anti-psychotics and conventional anti-psychotics, mostly haloperidol with older drugs causing more severe side effects (Leucht 1999).While anti-psychotic medications demonstrate efficacy in providing short-term relief when a heavy user of amphetamines experiences psychosis, there is no evidence to guide decisions regarding long-term clinical care using these medications for preventing relapse to psychosis.
