Risk factors for cocaine-induced paranoia in cocaine-dependent sibling pairs.
OBJECTIVE
Cocaine-induced paranoia (CIP), an irrational intense suspicion of others, is a common manifestation of cocaine dependence. Both environmental and genetic factors are thought to play a role, but the specific nature of such contributions is poorly understood.


METHODS
Demographic, diagnostic, and cocaine-use data were obtained from 420 cocaine-dependent, genetically confirmed, full-sibling pairs (N=840 subjects) interviewed with the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA). Probands with and without CIP were compared; then, factors associated with sibling CIP status were analyzed by logistic regression. Alcohol dependence, a known heritable phenotype, was analyzed as a positive control.


RESULTS
Of 420 probands, 273 (65%) experienced CIP. Probands with CIP were more severely dependent upon cocaine, had an earlier age of onset, were more likely to smoke cocaine, and used cocaine less frequently during the preceding year. Independent analyses of siblings replicated two of the former (i.e., dependence severity and age of onset). Probands with CIP also had a non-significantly higher proportion of siblings with the trait (66% versus 59%). Probands with concurrent alcohol dependence were confirmed to have significantly higher rates of alcoholism among their siblings.


CONCLUSIONS
Severity of cocaine dependence and age of onset appear to be important risk factors for CIP. Concordance for CIP between siblings did not emerge as significant in our analyses.
Kalayasiri
Rasmon
R
Department of Psychiatry, Yale School of Medicine, New Haven, CT 06520, USA.
Kranzler
Henry R
HR
Weiss
Roger
R
Brady
Kathleen
K
Gueorguieva
Ralitza
R
Panhuysen
Carolien
C
Yang
Bao-Zhu
BZ
Farrer
Lindsay
L
Gelernter
Joel
J
Malison
Robert T
RT
D000328:Adult; D017668:Age of Onset; D000437:Alcoholism / Q000453:epidemiology / Q000235:genetics; D019970:Cocaine-Related Disorders / Q000150:complications*; D003710:Demography; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology; D010259:Paranoid Disorders / Q000139:chemically induced* / Q000453:epidemiology / Q000523:psychology*; D010641:Phenotype; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index; D035781:Siblings / Q000523:psychology*