Abstract
Background. There is a body of literature on metamphetamine psychosis dating back to the 1950s with a recent resurgence of interest following increase in use worldwide. Distinct similarities appear to exist between metamphetamine psychosis and schizophrenia. Aims. The aim of this paper is to critically review the literature on metamphetamine psychosis. Method. Searches on Medline, Psycinfo and Cochrane were undertaken, references were followed and recent editions of major journals reviewed. There is a vast array of literature on stimulants and psychosis. I have deliberately limited my data to that on metamphetamines, only citing other data if particularly well known and relevant to distinguish. Data in Japanese has been quoted with reference to where cited. Results. Metamphetamine psychosis has been observed as a paranoid hallucinatory state developing gradually with repeated metamphetamine abuse and possibly continueing after metamphetamine withdrawal. Also noted is a lasting susceptibility to recurrence of the paranoid hallucinatory state with neuroleptics preventing this recurrence. Patients with persistent metamphetamine psychosis can develop long lasting residual symptoms resembling negative symptoms of schizophrenia. In animals intermittent administration of smaller doses of metamphetamine appears to lead to augmentation of behaviour, and increases in dopamine and seretonin levels. Also it appears that a challenge injection or stress can cause the same responses, which are inhibited by dopamine antagonists. Larger repeated doses of metamphetamine appear to lead to long lasting depletion of dopamine and seretonin. Conclusions and clinical importance. There are clear clinical similarities between metamphetamine psychosis and schizophrenia altered in both conditions with the use of antipsychotics. A major as yet unanswered question is whether metamphetamine can cause schizophrenia. The literature describes a number of changes in dopamine and seretonin systems. More research in this field could increase our understanding of transmitters and receptors, thereby helping our quest in improved drug development for both illnesses. Declaration of interest. Nil.
Keywords: metamphetamine, psychosis, schizophrenia, dopamine, seretonin
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