Relationship of positive and negative symptoms to cocaine abuse in schizophrenia

The prevalence of cocaine abuse by patients with schizophrenia has led researchers to investigate features of the disorder correlated with abuse. Although abuse has been found to be more common among patients with a diagnosis of paranoid subtype and a history of earlier and more frequent hospitalizations, it is unclear if it is related to any particular pattern of negative or positive symptoms. This study examines the severity of positive and negative symptoms for patients with and without histories of cocaine abuse. Subjects with a history of at least 2 months of cocaine abuse (N = 25), no lifetime substance abuse (N = 20), and 2 months of alcohol abuse with no other substance abuse (N = 23) are compared on five-factor analytically and three rationally derived scores from the Positive and Negative Syndrome Scale (PANSS). Following a multivariate analyses of variance (p < .01), univariate analyses indicated significant differences on the negative syndrome scales, with cocaine-abusing subjects exhibiting less severe negative symptoms than subjects with no substance-abuse history. Cocaine-abusing subjects were also found to have been younger at time of first psychiatric hospitalization and more likely to qualify for a diagnosis of the paranoid subtype.