Toward the identification of a specific psychopathology of heroin use disorder: biochemical and clinical correlations

Proteomic can undoubtedly offer valuable new insight into the study of drug addiction, in particular into the identification of potential biomarkers to assist in diagnosis and prognosis. Identifying abnormal levels of proteins or metabolites in body fluids can directly help clinicians to identify certain drug users from others or distinct the addiction stages during drug use. This study was a cohort, non interventional pilot study, with treatment of usual procedure consistent with the real world practice. The main aim of the study was to look for potential biomarkers of heroin addiction. To do this, proteomic profiles of human saliva were analysed in heroin use disorder individuals at treatment entry (individuals using daily street heroin); the procedure was then repeated in the same subjects after treatment stabilization with methadone. Correlations between serum level of methadone and clinical variables was also performed. Particularly, psychopathological domains (the heroin use disorder 5 specific psychopathological factors), behavioural covariates of craving, and stress-reaction have been compared in the same individuals at treatment entry and after pharmacological stabilization. The results showed a few variations into proteomic profile of heroin use disorder (HUD) individuals entering methadone treatment and after 6 months of continuous methadone treatment. Opposite than at T0, proteomic profiles showed greater dishomogeneity among individuals after 6 months of pharmacological intervention. The proteins, which showed variations, were those belonging to the immune response, thioredoxin, albumin, prolactin-inducing protein and cystatins. Interestingly amylases showed an apparent correlation with the 5 specific psychopathological domains. From a clinical perspective, all HUD individuals improved after treatment. The 5 main domains of psychopathology showed a significant reduction in severity, but the typology was stable from a qualitative point a view even after methadone treatment. Addictive behaviours and sensitivity to stress exhibited a great improvement. Regarding to methadone dosage, no correlation was found between dosage taken orally and blood level concentration. A positive correlation between methadone dosage and severity of cue induced/environmental addicted behaviour was found while there was a negative correlation between methadone blood concentration and maladaptive coping and arousal symptoms. In conclusions this study suggests that even in the field of substance use disorder it is possible to use correlations between patient clinical and biochemical characteristics for a better personalization of diagnostic and therapeutic interventions.