title: Factors affecting severity of positive and negative symptoms of psychosis in a polysubstance using population with psychostimulant dependence.
abstract: Approximately half of psychostimulant users experience psychotic symptoms, which include both positive and negative symptoms. Prior reports have exclusively used positive symptoms to characterize psychostimulant associated psychosis. Symptoms vary dramatically in severity, though most investigations categorize psychosis as a dichotomous occurrence. To explore the association between different substances of abuse and the severity of psychotic symptoms, we investigated 171 individuals meeting DSM-IV-TR criteria for psychostimulant (cocaine or methamphetamine) dependence in an observational cross-sectional study. Participants were predominantly male (72.5%), recruited from a socially disadvantaged neighborhood in Vancouver, Canada, with a mean age of 45.5(±8.8) years. Of the total sample, 85% were dependent on cocaine, and 28.1% were dependent on methamphetamine. Participants had a median total PANSS score of 63, ranging from 37 to 111. Demographic information, current substance use and early substance exposure were used to predict positive and negative psychotic symptom severity in linear regression models. Increased severity of positive psychotic symptoms was significantly related to greater methamphetamine and marijuana use in the past 28 days, and methadone-abstinence. Negative symptom severity was related to increased opioid use in the past 28 days. There was no overlap between predictors of positive and negative symptom severity.
authors.affiliation: Department of Psychiatry, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3.
authors.forename: Taylor S
authors.initials: TS
authors.lastname: Willi
authors.affiliation: Department of Psychiatry, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3.
authors.forename: William G
authors.initials: WG
authors.lastname: Honer
authors.affiliation: Department of Psychology, Simon Fraser University, Burnaby, B.C., Canada V5A 1S6.
authors.forename: Allen E
authors.initials: AE
authors.lastname: Thornton
authors.affiliation: Department of Psychology, Simon Fraser University, Burnaby, B.C., Canada V5A 1S6.
authors.forename: Kristina
authors.initials: K
authors.lastname: Gicas
authors.affiliation: Department of Psychiatry, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3.
authors.forename: Ric M
authors.initials: RM
authors.lastname: Procyshyn
authors.affiliation: Department of Psychiatry, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3.
authors.forename: Fidel
authors.initials: F
authors.lastname: Vila-Rodriguez
authors.affiliation: Department of Psychiatry, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3.
authors.forename: William J
authors.initials: WJ
authors.lastname: Panenka
authors.affiliation: Department of Pharmacology, 2176 Health Sciences Mall, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3.
authors.forename: Ana
authors.initials: A
authors.lastname: Aleksic
authors.affiliation: Department of Psychiatry, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3.
authors.forename: Olga
authors.initials: O
authors.lastname: Leonova
authors.affiliation: Department of Psychiatry, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3.
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Jones
authors.affiliation: Department of Psychiatry, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3.
authors.forename: G William
authors.initials: GW
authors.lastname: MacEwan
authors.affiliation: Department of Pharmacology, 2176 Health Sciences Mall, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3. Electronic address: albarr@interchange.ubc.ca.
authors.forename: Alasdair M
authors.initials: AM
authors.lastname: Barr
mesh_terms: D000328:Adult; D019969:Amphetamine-Related Disorders / Q000150:complications*; D002170:Canada; D000697:Central Nervous System Stimulants; D019970:Cocaine-Related Disorders / Q000150:complications*; D003430:Cross-Sectional Studies; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D008385:Marijuana Smoking; D008694:Methamphetamine; D008875:Middle Aged; D011605:Psychoses, Substance-Induced / Q000175:diagnosis* / Q000209:etiology; D012720:Severity of Illness Index
chemical_list: D000697:Central Nervous System Stimulants; D008694:Methamphetamine
keywords: Cocaine; Continuous; Marijuana; Methadone; Methamphetamine; Schizophrenia