Is Substance Abuse in Schizophrenia Related to Impulsivity, Sensation Seeking, or Anhedonia?
Abstract
OBJECTIVE: The authors compared impulsivity, sensation seeking, and anhedonia in a group of schizophrenic patients with and without lifetime substance abuse or dependence. METHOD: Patients (N=100) with schizophrenia or schizoaffective disorder (per DSM-III-R criteria) were assessed with the Composite International Diagnostic Interview’s section on psychoactive substance use disorder, the Positive and Negative Syndrome Scale, the Barratt Impulsivity Scale, the Zuckerman Seeking Sensation Scale, and the Chapman Physical Anhedonia Scale. RESULTS: The mean scores for impulsivity and sensation seeking were higher in the group with substance abuse (N=41) than in the group without substance abuse (N=59). No significant difference between groups was found regarding physical anhedonia. CONCLUSIONS: As in the general population, high levels of impulsivity and sensation seeking are associated with substance abuse in patients with schizophrenia.
The high prevalence of substance abuse in patients with schizophrenia has sometimes been interpreted as a means of self-medicating negative symptoms, anhedonia, depression, or neuroleptic side effects (1). However, although preclinical (2) and genetic studies (3) have given some theoretical consistence to this theory, clinical studies have lead to discrepant conclusions. One hypothesis is that in nonschizophrenic patients, high levels of impulsivity (4) and sensation seeking (5) are associated with substance abuse, but this has been little studied in patients with schizophrenia. In limited samples, novelty seeking (6) or disinhibition (7) has been related to substance abuse. Our objective was to compare the occurrence of impulsivity, sensation seeking, and anhedonia in a group of patients with schizophrenia with and without lifetime substance abuse or dependence per DSM-III-R criteria.
Method
The study included 100 consecutively hospitalized inpatients (N=76) or outpatients (N=24) with diagnoses of schizophrenia (N=91) or schizoaffective disorder (N=9) according to DSM-III-R. The study was approved by the local ethics committee, and all subjects provided their informed consent. The psychoactive substance use disorders section of the Composite International Diagnostic Interview (8) was used to make computerized DSM-III-R diagnoses of abuse of or dependence on alcohol, cannabis, amphetamines, sedatives, opioids, cocaine, hallucinogens, phencyclidine, inhalants, and other substances. Patients were assessed with the Positive and Negative Syndrome Scale for schizophrenic symptoms (9), the Barratt Impulsivity Scale (a 34-item self-report) (10), the Zuckerman Sensation Seeking Scale (form V) (a 40-item self-report) (11), and the Chapman Physical Anhedonia Scale (a 61-item self-report) (12).
Subjects with lifetime abuse or dependence (substance-abusing patients) were compared to subjects without abuse or dependence. Quantitative variables were studied by using analyses of covariance (ANCOVAs) adjusted on the basis of age and gender since these variables could be confounding factors. Since there was a statistical interaction between gender for Positive and Negative Syndrome Scale scores, we used these scores as covariates together with sex and group in a comparison of scores on the Barratt Impulsivity Scale and the Zuckerman Sensation Seeking Scale. Subjects without lifetime substance abuse were further compared to subjects with past abuse or dependence, defined by the disappearance of DSM-III-R criteria for abuse or dependence at least six months before assessment. All tests were two-tailed, with an alpha set at 0.05.
Results
Forty-one subjects had lifetime abuse or dependence for one (N=24) or more (N=17) substances, mainly alcohol (N=27) and cannabis (N=27). Cocaine dependence occurred in only one subject. Only eight subjects met the criteria for abuse. Thirty-three substance-abusing patients were male (80.5%) compared to 35 (59.3%) in the group without lifetime substance abuse or dependence (χ2=4.98, df=1, p=0.03), and the substance abusers were significantly younger (mean=31.3 years, SD=7.1, versus mean=37.1, SD=12.3) (ANCOVA, F=7.20, df=1, 96, p=0.009). No significant difference between the two groups was found for other demographic or clinical variables, including age of first psychiatric treatment, number of hospitalizations, and scores on the Positive and Negative Syndrome Scale and the Chapman Physical Anhedonia Scale. In the group with substance abuse, Barratt Impulsivity Scale and Sensation Seeking Scale scores were significantly higher than in the group without substance abuse (Table 1).
In the past abuse or dependence subgroup (N=15), Barratt Impulsivity Scale scores were higher (men: N=10, mean=69.7, SD=11.5; women: N=5, mean=59.8, SD=9.9) than in the group without abuse or dependence (men: N=35, mean=53.5, SD=15.3; women: N=24, mean=49.8, SD=15.4) (ANCOVA, F=8.14, df=1, 66, p=0.006). Zuckerman Sensation Seeking Scale scores were also found to be higher in the subgroup with past abuse or dependence, but the difference did not reach statistical significance (ANCOVA, F=2.80, df=1, 66, p=0.09).
Discussion
Our results do not support the self-medication hypothesis of substance abuse in schizophrenia (1). Indeed, substance-abusing patients were not significantly different from those without substance abuse with regard to physical anhedonia or scores on the Positive and Negative Syndrome Scale negative subscale or scores for anxiety or depression. The self-medication hypothesis has especially been suggested for cocaine abuse, which is less widespread in Europe than in North America for reasons of availability. Our results indicate that schizophrenic patients with a lifetime comorbidity of substance abuse or dependence are more impulsive and seek more intense sensations than schizophrenic patients without abuse or dependence. The persistence of higher scores on the Barratt Impulsivity Scale in the subgroup with past abuse or dependence suggests that impulsivity is not induced by alcohol or drugs, although no definitive conclusion can be reached. Our findings are consistent with those of Blanchard et al. (7) and with those obtained by our group in an independent study (unpublished report by Gut-Fayand et al.): substance abuse in schizophrenic patients, as in nonschizophrenic patients, is related to personality components.
Several limitations to this study can be raised. First, the representativity of our study group can be challenged, although the exhaustive recruitment process limited the selection bias. Second, as in any retrospective study, the prevalence of lifetime substance abuse may have been underestimated, but urinary toxicology tests would not have been able to improve the detection of former substance abuse. A prospective longitudinal follow-up study of a cohort of adolescents, examining the occurrence of substance abuse and/or schizophrenia, would be more reliable but hardly feasible.
Conclusions
We suggest that impulsivity and sensation seeking are more clinically relevant than anhedonia as risk factors for substance abuse in schizophrenia. The nature of the link between the susceptibility to substance abuse and schizophrenia (common susceptibility or the addition of risk factors) remains to be identified.
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Presented at the 153rd annual meeting of the American Psychiatric Association, Chicago, May 13–18, 2000. Received Jan. 11, 2000; revisions received May 1, July 19, and Aug. 30, 2000; accepted Sept. 14, 2000. From the Service Hospitalo-Universitaire de Santé Mentale et Thérapeutique, Université René Descartes, Paris; the Centre Hospitalier Sainte-Anne 75014, Paris; and the Service de Psychiatrie, BP 27 Centre Hospitalier Général. Address reprint requests to Dr. Dervaux, Service de Psychiatrie, BP 27 Centre Hospitalier Général, F 91401 Orsay, France; [email protected] (e-mail).
1. Mueser KT, Drake RE, Wallach MA: Dual diagnosis: a review of etiological theories. Addict Behav 1998; 23:717–734Crossref, Medline, Google Scholar
2. Self DW, Nestler EJ: Molecular mechanisms of drug reinforcement and addiction. Annu Rev Neurosci 1995; 18:463–495Crossref, Medline, Google Scholar
3. Krebs MO, Sautel F, Bourdel MC, Sokoloff P, Schwartz JC, Olié JP, Loo H, Poirier MF: Dopamine D3 receptor gene variants and substance abuse in schizophrenia. Mol Psychiatry 1998; 3:337–341Crossref, Medline, Google Scholar
4. Johnson WL, Malow RM, Corrigan SA, West JA: Impulsive behavior and substance abuse, in The Impulsive Client: Theory, Research, and Treatment. Edited by McCown WG, Johnson JL, Shure MB. Washington, DC, American Psychological Association, 1996, pp 225–246Google Scholar
5. Kosten TA, Ball SA, Rounsaville BJ: A sibling study of sensation seeking and opiate addiction. J Nerv Ment Dis 1994; 182:284–289Crossref, Medline, Google Scholar
6. Van Ammers EC, Sellman JD, Mulder RT: Temperament and substance abuse in schizophrenia: is there a relationship? J Nerv Ment Dis 1997; 185:283–288Google Scholar
7. Blanchard JJ, Squires D, Henry T, Horan WP, Bogenschutz M, Lauriello J, Bustillo J: Examining an affect regulation model of substance abuse in schizophrenia: the role of traits and coping. J Nerv Ment Dis 1999; 187:72–79Crossref, Medline, Google Scholar
8. Robins LN, Wing J, Wittchen HU, Helzer JE, Babor TF, Burke J, Farmer A, Jablenski A, Pickens R, Regier DA, Sartorius N, Towle LH: The Composite International Diagnostic Interview: an epidemiologic instrument suitable for use in conjunction with different diagnostic systems and in different cultures. Arch Gen Psychiatry 1988; 45:1069–1077Google Scholar
9. Kay SR, Opler LA, Spitzer RL, Williams JB, Fiszbein A, Gorelick A: SCID-PANSS: two-tier diagnostic system for psychotic disorders. Compr Psychiatry 1991; 32:355–361Crossref, Medline, Google Scholar
10. Patton JH, Stanford MS, Barratt ES: Factor structure of the Barratt Impulsiveness Scale. J Clin Psychol 1995; 51:768–774Crossref, Medline, Google Scholar
11. Zuckerman M: Sensation seeking, in Psychopathic Behavior: Approaches to Research. Edited by Hare RD, Schalling D. New York, John Wiley & Sons, 1978, pp 165–185Google Scholar
12. Chapman LJ, Chapman JP, Raulin ML: Scales for physical and social anhedonia. J Abnorm Psychol 1976; 4:374–382Crossref, Google Scholar
