Towards a specific psychopathology of Substance Use Disorder: Comparison between Heroin Use Disorder and chronic psychotic patients

Background: Addiction is a chronic relapsing condition in which psychiatric phenomena play a crucial role. Psychopathological symptoms in patients with Substance Use Disorders (SUDs) are generally considered to be part of the drug addict personality, or else to be related to the presence of a Dual Disorder (DD), raising doubts about whether patients with long-term SUD possessed psychopathological dimensions. Our research group at the University of Pisa has shed light on the possible definition of a specific psychopathy dimension in SUD. In Heroin Use Disorder (HUD) patients, by applying a PCA factor analysis to the 90 items listed in the SCL90 checklist, a 5-factor solution was identified for the first time and was then confirmed in Alcohol Use Disorder and Cocaine Use Disorder patients. The first factor reflected a depressive 'Worthlessness-Being Trapped' dimension (W/BT); the second factor picked out a 'Somatic Symptoms' dimension (SS); the third identified a 'Sensitivity-Psychoticism' dimension (S/P); the fourth a 'Panic Anxiety' dimension (PA); and the fifth a 'Violence-Suicide' dimension (V/S). To confirm their specificity, these dimensions must be able to discriminate patients affected by addiction from those affected by other psychiatric diseases. Methods: In this study 40 chronic psychotic patients (CHR-PSY) were matched with 33 HUD patients according to age and gender, and compared, at univariate and multivariate level, regarding the severity and typology of the SCL90 five dimensions. Results: Low-level education was more frequent in HUD patients, but it was unrelated to psychopathological typology (chi(2)=8.83; p=0.065) and to severity (except for the SS dimension, F=5.94; p<0.05). Psychopathological typology was able to differentiate HUD from CHR-PSY patients (chi(2)=14.44; p=0.006). At univariate level, only PA severity was higher in CHR-PSY patients, whereas multivariate discriminant analysis was able to differentiate HUD significantly from CHR-PSY patients Lambda=0.69; chi(2)=25.74; df=2; p<0.001), showing that 79.5% of the cases, as originally grouped, had been correctly classified. Conclusions: This study, being able to differentiate HUD from CHR-PSY patients, further supports the specificity of the proposed factorial dimensions of the psychopathology of SUD.