SUBSTANCE-ABUSE AS A RISK FACTOR FOR TARDIVE-DYSKINESIA - A RETROSPECTIVE ANALYSIS OF 1,027 PATIENTS

Tardive dyskinesia (TD) affects between 10 and 50 percent of all patie nts on long-term antipsychotic therapy, depending on the population st udied, Various risk factors for TD have been reported; a correlation b etween TD and substance abuse has been suggested in some reports and n ot found in others, This study analyzes the association of substance a buse with the incidence of tardive dyskinesia in a schizophrenic popul ation. All patients at the West Side Veterans Affairs Medical Center a re evaluated prior to the initiation of neuroleptic therapy with the D yskinesia Identification System: Condensed User Scale (DISCUS); those with a diagnosis of schizophrenia, schizoaffective disorder, or schizo phreniform disorder during the years 1986 through 1993 were included i n this analysis, History of substance abuse was considered positive if there was clinician report or diagnosis of substance abuse. These dat a were collected and analyzed using ANOVA. In a sample of 1,027 subjec ts (97% male), 83.2 percent had a neuroleptic exposure of 10 or more y ears, and slightly more than half (50.8 percent) had a positive histor y of substance abuse, Using research diagnostic criteria, 28.9 percent of the sample had tardive dyskinesia, Analysis of variance showed his tory of substance abuse (p<.000) and years on neuroleptics (p<.000) to be strongly correlated to a diagnosis of TD. Age was less strongly co rrelated to the DISCUS score (p<.01), and there was no association of TD with diagnosis (p=.237). This study therefore demonstrates a robust correlation between To and substance abuse, A mechanism of action inv olving N-methyl-D-aspartate (NMDA)-mediated excitotoxicity is proposed .