Impulsivity, Sensation Seeking and Anhedonia as Possible Explanations forCannabis Abuse Comorbidity among First Psychotic Episode Inpatients

Objective: There have been relatively few reported carefully constructed studies to date concerning the link between psychoactive substance abuse among first-episode psychotic individuals and specific behavioral aspects that might clarify the comorbidity. Using standard toxicological testing, we compared consecutively admitted inpatients diagnosed with first psychotic episode with and without lifetime and/or active (last month) cannabis abuse or dependence and the levels of impulsivity, sensation seeking and anhedonia. Methods: Ninety-one consecutively admitted psychiatric patients diagnosed using the DSM-IV criteria with a first psychotic episode due to schizophrenia, schizophreniform disorder, bipolar disorder, brief psychotic episode, and psychosis NOS disorder were included in the study. Patients were aged 18 to 41 (mean 27.1+9.2); seventy-six of the patients (83.5%) were males. Standard urine tests for tetrahydrocannabinol (THC) were performed and self-report questionnaires were administered during the first 48 h after admission. The following rating scales were used: the PANSS (Positive and Negative Syndrome Scale), the Barratt Impulsivity Scale (a 34-item self-report), the Zuckerman Sensation-Seeking Scale (form V), and the Chapman Physical Anhedonia Scale (a 61-item self-report). Results: According to bivariate correlations, the PANSS Positive Scale was significantly correlated with the Barratt Rating Scale (0.260; p ≤ 0.05) and the PANSS Negative with Physical Anhedonia Scale (0.389, p ≤ 0.001). Rates for the Zuckerman Rating Scale (f=20.1, p ≤ 0.001) and the Barratt Rating Scale (f=5.15, p ≤ 0.05) were significantly higher in the group of cannabis abusers with no clear difference between abusers and nonusers in the PANSS and the Physical Anhedonia Scale. Conclusion: The results of the study showed high levels of impulsivity and sensation seeking in the group of inpatients suffering from first psychotic episode and cannabis abuse comorbidity compared to first-episode inpatients with no substance abuse.