title: The impact of cannabis use on age of onset and clinical characteristics in first-episode psychotic patients. Data from the Psychosis Incident Cohort Outcome Study (PICOS).
abstract: Cannabis use is frequent among first-episode psychosis (FEP) patients and has been associated with several clinical features. This study aimed in an FEP sample to determine whether cannabis use is associated with (1) a higher level of positive symptoms, a lower level of depression and a better premorbid adjustment, (2) an earlier age of onset, and a better premorbid IQ. The study was conducted within the framework of the Psychosis Incident Cohort Outcome Study (PICOS), a multisite collaborative research on FEP patients who attended the psychiatric services in Veneto Region, Italy. Standardized instruments were used to collect sociodemographic, clinical, and drug use data. A total of 555 FEP patients met the inclusion criteria, 517 of whom received an ICD-10 diagnosis of psychosis; 397 (55% males; mean age: 32 yrs ± 9.5) were assessed. Out of these, 311 patients agreed to be interviewed on drug and alcohol misuse; 20.3% was positive for drug misuse: cannabis (19.0%), cocaine (3.9%), and hallucinogens (3.9%). Cannabis use was not associated with a higher level of positive symptoms, but correlated with less severe depressive symptoms. No relationship was observed between premorbid adjustment or IQ and cannabis use. FEP patients who used cannabis had an earlier age of onset than abstinent patients, even after adjusting for gender and diagnosis. Our results suggest a possible causal role of cannabis in triggering psychosis in certain vulnerable subjects. Particular attention must be paid to this behaviour, because reducing cannabis use can delay or prevent some cases of psychosis.
authors.affiliation: Department of Public Health and Community Medicine, Section of Psychiatry, University of Verona, 37134 Verona, Italy. sarah.tosato@univr.it
authors.forename: Sarah
authors.initials: S
authors.lastname: Tosato
authors.forename: Antonio
authors.initials: A
authors.lastname: Lasalvia
authors.forename: Chiara
authors.initials: C
authors.lastname: Bonetto
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Mazzoncini
authors.forename: Doriana
authors.initials: D
authors.lastname: Cristofalo
authors.forename: Katia
authors.initials: K
authors.lastname: De Santi
authors.forename: Mariaelena
authors.initials: M
authors.lastname: Bertani
authors.forename: Sarah
authors.initials: S
authors.lastname: Bissoli
authors.forename: Lorenza
authors.initials: L
authors.lastname: Lazzarotto
authors.forename: Giovanna
authors.initials: G
authors.lastname: Marrella
authors.forename: Dario
authors.initials: D
authors.lastname: Lamonaca
authors.forename: Rosanna
authors.initials: R
authors.lastname: Riolo
authors.forename: Francesco
authors.initials: F
authors.lastname: Gardellin
authors.forename: Anna
authors.initials: A
authors.lastname: Urbani
authors.forename: Michele
authors.initials: M
authors.lastname: Tansella
authors.forename: Mirella
authors.initials: M
authors.lastname: Ruggeri
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000704:Analysis of Variance; D002188:Cannabis; D015331:Cohort Studies; D015897:Comorbidity; D003866:Depressive Disorder / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology* / Q000523:psychology*; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods* / Q000706:statistics & numerical data; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011618:Psychotic Disorders / Q000453:epidemiology* / Q000523:psychology*; D055815:Young Adult