Psychological Medicine



Pre-morbid characteristics and co-morbidity of methamphetamine users with and without psychosis


C.-K. CHEN a1, S.-K. LIN a1, P. C. SHAM a1, D. BALL a1, E.-W. LOH a1, C.-C. HSIAO a1, Y.-L. CHIANG a1, S.-C. REE a1, C.-H. LEE a1 and R. M. MURRAY a1c1
a1 Department of Psychiatry, Chang Gung Memorial Hospital, and Department of Addiction Science, Taipei City Psychiatric Centre, Taiwan; and Division of Psychological Medicine, Institute of Psychiatry, London

Article author query
chen c-k   [PubMed][Google Scholar] 
lin s-k   [PubMed][Google Scholar] 
sham p   [PubMed][Google Scholar] 
ball d   [PubMed][Google Scholar] 
loh e-w   [PubMed][Google Scholar] 
hsiao c-c   [PubMed][Google Scholar] 
chiang y-l   [PubMed][Google Scholar] 
ree s-c   [PubMed][Google Scholar] 
lee c-h   [PubMed][Google Scholar] 
murray r   [PubMed][Google Scholar] 

Abstract

Background. The long-term use of methamphetamine (MAMP) can result in psychosis but it is not clear why some individuals develop psychotic symptoms, while others use MAMP regularly over long periods and remain unscathed. We set out to characterize MAMP users and to examine the relationship of pre-morbid personality, pre-morbid social function and other psychiatric disorders to MAMP psychosis.

Method. Four hundred and forty-five amphetamine users were recruited from a psychiatric hospital and a detention centre in Taipei, and were assessed with the Diagnostic Interview for Genetic Studies (DIGS). Their parents were interviewed with the Premorbid Schizoid and Schizotypal Traits (PSST) and the Premorbid Social Adjustment (PSA) schedules. Pre-morbid characteristics and psychiatric co-morbidity were compared between the MAMP users with a lifetime diagnosis of MAMP psychosis and those without.

Results. The MAMP users with psychosis presented a clinical picture which mimicked the positive symptoms of schizophrenia: 85% had auditory hallucinations; 71% persecutory delusions; 63% delusions of reference. Compared with their non-psychotic counterparts, these MAMP users were younger at first MAMP use, used larger amounts of MAMP, had a significantly higher mean PSST score, and higher rates of major depressive disorder, alcohol dependence and antisocial personality disorder.

Conclusions. Earlier and larger use of MAMP was associated with increased risk of psychosis. Our data are also compatible with the view that pre-morbid schizoid/schizotypal personality predisposes MAMP users to develop psychosis, and that the greater the personality vulnerability, the longer the psychosis will persist.


Correspondence:
c1 Professor Robin M. Murray, Division of Psychological Medicine, Institute of Psychiatry, De Crespigny Park, London SE5 8AF.


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