Risk factors for methamphetamine-induced paranoia and latency of symptom onset in a Thai drug treatment cohort

ABSTRACT

Background: Methamphetamine (MA) produces a range of psychotic experiences, ranging from a sub-syndromal symptom to a full-scale psychosis. While the characteristics of and risk factors for MA-psychosis have been studied extensively, MA-induced paranoia (MIP) has received only limited attention.Methods: Demographic, diagnostic, and drug use variables were assessed in 96 experienced MA-users from a Thai drug treatment center using the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA) and the Methamphetamine Experienced Questionnaire (MEQ). Individuals with and without MIP were compared. Latency of the initial symptom onset was also examined.Results: Ninety-six subjects participated in the study including 44 (46%) endorsed MIP. Individuals with MIP were dependent on MA more severely than those without the trait (p=0.02). Subjects with MIP were also more likely to use solvents (p=0.03), be dependent on alcohol (p=0.048), and attempt suicide (p=0.04) than those without. Individuals with short latency to a first MIP episode (i.e., within two years of their first use of MA) did not differ from those with prolonged latency (≥ 3 years) with respect to MA use at symptom onset. However, they reported lower lifetime use (p=0.007), heaviest period use (p=0.008) and past-year MA use (p=0.04) than those with later onset.Conclusion: Severe dependence on MA, solvent use, alcohol dependence, and suicide attempts were associated with MIP. Though the vulnerability to MIP was associated with greater dependence severity as a group, those who experience MIP earlier in the course of their dependence reported less MA use than those in whom symptoms arose later. This suggests a subgroup of individuals that are intrinsically more vulnerable to the MA effects (e.g., habit forming and psychotic effects) and in whom MIP’s subjectively aversive effects may lead to reduced MIP use over the course of their MA dependence.