The epidemiology and progression time from transient to permanent psychiatric disorders of substance-induced psychosis in Taiwan.

Introduction: Substance-induced psychosis (SIP), including alcohol-induced psychotic disorder (AIPD) and substance-induced psychotic disorder (SIPD), is gradually increasing in importance in clinical practice. However, few studies have investigated the epidemiology and progression time from transient to permanent psychiatric disorders for AIPD and SIPD patients.

Methods: We utilized the National Health Insurance Research Database (NHIRD) to investigate the incidence and prevalence of AIPD and SIPD in Taiwan and determined the timing of AIPD or SIPD followed by the development of persistent psychotic conditions.

Results: The average incidence and prevalence were 1.97 and 2.94 per 100,000 person-years for AIPD, 3.09 and 5.67 per 100,000 person-years for SIPD in Taiwan. Moreover, 10.9% to 24.3% of subjects with either AIPD or SIPD had a change in diagnosis to either schizophrenia or affective disorder, and ~50% of patients had a psychotic or affective transformation in their first year after AIPD and SIPD diagnoses. The mean progression time of psychotic or affective transformation was 1.9 to 2.7 years.

Conclusions: SIP is a predictive factor for persistent psychotic and affective transformation, and a three-year follow-up may be an optimal clinical practice to prevent psychotic or affective transformation in 60% of patients.