Revista de Psicologia Forense

Abstrato

The Measurement of Substance Use in Forensic Schizophrenia Spectrum Disorders-Initial Validation of a New Scale

Pierre Titeca

Background: Mainstream substance abuse assessment schemes do not grasp the specific consequences of substance abuse (SA) in a) schizophrenia in patients and b) forensic settings. In the current study, we present the initial validation stages of a new scale measuring substance abuse and its consequences specifically for schizophrenia spectrum disorders (SZ) in forensic settings. Methods: This observer-rated scale was elaborated through clinical observations in a medium-secure forensic unit for SZ. This 52-item scale measures antecedents, quantitative aspects of the SA, immediate effects, reasons for use, insight, cessation attitudes, transgressions (e.g. smuggling or extortion) and consequences through all-available indications. This scale was tested in three groups of forensic patients with SZ (n=112). Results: We found good internal consistency and interrater agreement estimates, good agreement between our scale and diagnoses of SA, moderate to strong relations with clinical functioning, risk estimates and psychopathy. Prevalences reported through this new scale are congruent with international literature. Differential patterns of scores based on substance(s) being used were observed. Conclusions: This new scale appeared to grasp for the clinical variety of SA in forensic schizophrenia inpatients in psychometrically sound way. The instrument appeared to be user-friendly enough not to require specific training or long uptake.