Patterns of substance abuse in Schizophrenia: Nature and significance

Abstract

Recent literature suggests that the increasingly prevalent problem of substance abuse may have important implications for the symptoms and course of schizophrenia. To further examine the impact of substance abuse on this disorder, the clinical and research charts of 67 schizophrenic patients admitted to the Schizophrenia Program of the University of Michigan between 1987 and 1990 were reviewed and data on symptomatology, history of substance use, age at onset and first hospitalization, and family psychiatric history were gleaned. This information was analyzed with respect to clinical, demographic, and outcome variables with the following findings: (i) female subjects abused substances at a much lower rate (20%) than male subjects (48%); (ii) substance-abusing patients with schizophrenia had lower pre- and post-treatment Hamilton Rating Scale of Depression scores, poorer post-discharge treatment compliance, and were younger at first hospitalization than were non-abusing patients; (iii) the most often abused substance was cannabis (28%) followed closely by alcohol (21%), with cocaine, hallucinogens, and stimulants all abused by significantly fewer patients; (iv) rates of family history of schizophrenia were similar in substance-abusing and non-substance-abusing schizophrenic patients. These data suggest that substance abuse may not be etiologically related to schizophrenia but influences the onset, course, and symptomatology of schizophrenia.

Cannabis and Neurological Soft Signs in Schizophrenia: Absence of Relationship and Influence on Psychopathology

“…Several authors proposed cannabis to be a possible risk factor for onset [5][6][7] and course of schizophrenia [1,8,9]; the high frequency of a 'dual diagnosis', estimated between 15.4 and 64.7% [1], tends to give credit to an aetiological hypothesis [10][11][12]. Although suggestive, this hypothesis is countered by the fact that the incidence of schizophrenia did not increase over the last decades, despite increasing prevalence of substance abuse [13].…”

Gamma Vinyl-GABA Differentially Modulates NMDA Antagonist-Induced Increases in Mesocortical Versus Mesolimbic DA Transmission

“…GABAergic modulation in schizophrenia (Dean et al 1999 or for review see Keverne 1999), although pharmacotherapy with current GABAergic agents has been limited by the high abuse liability of these compounds (Koob 1998), and the increased susceptibility to addiction found in schizophrenic patients (Cuffel et al 1993;DeQuardo et al 1994). Our findings , combined with data from Takada and coworkers (Takada and Yanagita 1997) demonstrate that, unlike many receptor-mediated GABA agonists, GVG itself is not addictive.…”

Comparison of Sociodemographic and Clinical Variables in Schizophrenics With and Without Substance Abuse

“…8,14,15 Some studies found Cannabis as the predominantly abused substance. 16,17 The most commonly used combination of drugs was alcohol and cannabis. Cocaine, opiates, and sedatives were the other substances.…”