McKetin R, Clare PJ, Castle D, Turner A, Kelly PJ, Lubman DI, Arunogiri S, Manning V, Berk M. How does a family history of psychosis influence the risk of methamphetamine-related psychotic symptoms: Evidence from longitudinal panel data.
Addiction 2023;
118:1975-1983. [PMID:
37157055 PMCID:
PMC10952942 DOI:
10.1111/add.16230]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 04/24/2023] [Indexed: 05/10/2023]
Abstract
AIMS
To determine whether the risk of psychotic symptoms during weeks of methamphetamine use was dependent on, increased by, or independent of having a family history of psychosis.
DESIGN
Secondary analysis of 13 contiguous 1-week periods of data (1370 weeks). A risk modification framework was used to test each scenario.
SETTING
Geelong, Wollongong and Melbourne, Australia.
PARTICIPANTS
Participants in a randomized controlled trial of treatment for methamphetamine dependence (n = 148) who did not have a primary psychotic disorder on enrolment.
MEASUREMENTS
Psychotic symptoms in the previous week were defined as a score of 3+ on any of the Brief Psychiatric Rating Scale items of hallucinations, unusual thought content or suspiciousness. Any (vs no) methamphetamine use in the previous week was assessed using the Timeline Followback method. Self-reported family history of psychosis was assessed using the Diagnostic Interview for Psychosis.
FINDINGS
The risk of psychotic symptoms in the past week was independently associated with methamphetamine use in that week (relative risk [RR] = 2.3, 95% CI = 1.3-4.3) and with having a family history of psychosis (RR = 2.4, 95% CI = 0.9-7.0); the joint risk among participants with a family history of psychosis during weeks when they were using methamphetamine was large (RR = 4.0, 95% CI = 2.0-7.9). There was no significant interaction between a family history of psychosis and methamphetamine use in predicting psychotic symptoms (interaction RR = 0.7 95% CI = 0.3-1.8), but there was a small non-significant excess risk due to the interaction (0.20 95% CI = -1.63 to 2.03).
CONCLUSIONS
Among people dependent on methamphetamine, the relative risk of psychotic symptoms during weeks of methamphetamine use does not appear to be dependent on, or increased by, having a family history of psychosis. However, a family history of psychosis does appear to be an independent risk factor that contributes to the absolute risk of psychotic symptoms in this population.
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