THE THEORY OF MIND AND PSYCHOTIC SYMPTOMS PHENOMENOLOGY IN SUBSTANCE-INDUCED PSYCHOTIC DISORDER AND SCHIZOPHRENIA

The study aimed to determine clinical indicators that could be used to differentiate between patients diagnosed with substance-induced psychotic disorder (SIPD) and patients diagnosed with schizophrenia by comparing their psychotic symptoms and theory of mind (ToM).

The study included 43 male patients diagnosed with schizophrenia according to DSM-5 criteria and 43 male patients diagnosed with SIPD. The patients were administered the Sociodemographic and Clinical Data Form, Scale for the Assessment of Positive Symptoms (SAPS), Scale for the Assessment of Negative Symptoms (SANS), Psychotic Symptom Evaluation Scale (PSYRATS), and Reading the Mind in the Eyes Test (RMET).

In patients diagnosed with schizophrenia, the scores on SAPS subscales for structural thought disorder and bizarre behavior, as well as SANS total scores, were significantly higher compared to patients diagnosed with SIPD (z=2.679, p=0.007; z=2.984, p=0.003; z=6.916, p<0.001). The scores for recognizing negative and neutral expressions on the RMET were significantly higher in patients with SIPD than in patients with schizophrenia (z=3.540; p<0.001; z=4.404, p<0.001). It was found that as the scores on the SANS total and Affect Blunting or Flattening subscale, as well as the scores on the SAPS Bizarre Behavior subscale decrease, the probability of having SIPD increases.

In patients diagnosed with SIPD, there are fewer disorganized and negative symptoms compared to patients diagnosed with schizophrenia. Patients with SIPD can recognize negative and neutral expressions better than patients with schizophrenia. When making a differential diagnosis between SIPD and schizophrenia, as blunting in affect, total negative symptoms, and severity of bizarre behavior decrease, the probability of being diagnosed with SIPD increases relative to the probability of being diagnosed with schizophrenia.