FRIDAY, Nov. 11 (HealthDay News) —Individuals with methamphetamine-related conditions have an increased risk of developing schizophrenia compared to other drug use disorders, and a similar risk to those with cannabis-use disorders, according to a study published online Nov. 8 in The American Journal of Psychiatry.
Russell C. Callaghan, Ph.D., from the Center for Addiction and Mental Health in Toronto, and colleagues assessed the correlation between methamphetamine use and later schizophrenia in a cohort of drug users initially free of persistent psychosis. Data were collected from hospital discharge records from 1990 to 2000 for 42,412 patients with methamphetamine-related conditions and those with other drug use (cocaine, opioid, alcohol, and cannabis groups) disorders. They were propensity score-matched to a population proxy comparison group of individuals with primary appendicitis. The methamphetamine cohort was matched to the other drug use cohorts, and the differences between matched groups in the rates of subsequent admission with schizophrenia diagnoses were estimated.
The investigators found a significantly higher risk of schizophrenia in the methamphetamine cohort than in the control appendicitis cohort (hazard ratio [HR], 9.37) and compared to the cocaine, opioid, and alcohol cohorts (HRs ranging from 1.46 to 2.81). There was no significant difference in the risk of schizophrenia in the methamphetamine or cannabis cohorts. In all drug cohorts there was an increased risk of schizophrenia compared to the appendicitis cohort.
"Individuals with methamphetamine-related disorders have a higher risk of schizophrenia than those with other drug use disorders, with the exception of cannabis-use disorders," the authors write.
One author disclosed financial ties to the pharmaceutical industry. Another author disclosed receiving remuneration as an expert witness in cases regarding amphetamine toxicity.
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