Attention dysfunction in psychoses associated with novel psychoactive substances: a comparison with schizophrenia

<p style="text-align: justify;"><strong>Context and relevance.</strong> Differentiating between endogenous and exogenous psychoses remains one of the most challenging tasks in contemporary psychiatry, as productive symptoms largely overlap and do not allow for a clear distinction. In this context, cognitive markers—particularly attention parameters—gain diagnostic importance, as they may reflect underlying differences in the mechanisms of psychosis formation. <strong>Objective</strong><strong> </strong>is to provide a comparative analysis of the characteristics of attention in patients with acute psychoses induced by the use of NPS, and in patients with schizophrenia (F20). <strong>Hypothesis.</strong> Attention impairments in NPS-induced psychoses and schizophrenia differ across parameters: patients with schizophrenia are expected to demonstrate more stable and uniform decreases in attentional performance, whereas patients with NPS-psychoses are expected to show marked fluctuations in productivity, greater fatigability, and difficulties in attentional shifting. <strong>Materials and methods.</strong> The study included 133 inpatients of a psychiatric hospital: 72 with NPS-induced psychoses and 61 with schizophrenia (M = 31.3; SD = 7.57). Two standardized tools were employed to assess attentional functioning: the <em>Symbol Coding</em> subtest from the BACS battery, measuring processing speed and sustained attention, and the Schulte Tables, evaluating processing tempo, attentional shifting, and fatigability during serial task performance. <strong>Results.</strong> Significant differences were found between the groups. Patients with schizophrenia showed more pronounced deficits in sustained attention and overall processing efficiency. In contrast, patients with NPS-induced psychoses exhibited pronounced fluctuations in concentration, reduced attentional stability, and higher fatigability across serial tasks. <strong>Conclusions.</strong> The findings indicate qualitatively distinct mechanisms of attentional impairment in endogenous and exogenous psychoses. Schizophrenia is associated with a “rigid” type of deficit characterized by stable, uniform decline, while NPS-induced psychoses are marked by a “labile” type, including productivity fluctuations and rapid exhaustion. These distinctions hold diagnostic value for differentiating psychotic states and may inform the development of personalized cognitive remediation programs, as well as applications in forensic psychiatric evaluations where attentional control and behavioral regulation are under scrutiny.</p>