Measurement of platelet enzymatic activities in assessing the clinical response to antipsychotic therapy in patients with late-onset schizophrenia-like psychoses

Objective. To identify correlations between the levels of platelet enzyme activity and clinical responses to antipsychotic pharmacotherapy in patients diagnosed with late-onset manifesting schizophrenia-like psychosis (late-onset schizophrenia, LOS) and very late-onset manifesting schizophrenia-like psychosis (VLOSLP). Material and methods. The mental health status of 76 hospitalized patients with LOS and VLOSLP was evaluated using standardized psychometric scales at two time points: prior to the initiation of treatment and after a 28-day course of psychotropic therapy. Prior to treatment commencement, the activity levels of platelet enzymes involved in glutamate metabolism, energy metabolism, and glutathione antioxidant metabolism were measured for all subjects. A statistical analysis of the database with clinical and biochemical examination results, was conducted. Results. A comprehensive psychopathological assessment enabled the identification of patients exhibiting specific small-range delusions within their psychosis, notably «dwelling paranoid» delusions. It was observed that this type of delirium was predominantly present in patients with VLOSLP (X²=9.8, p=0.0018 with Yates correction). When participants were categorized into subgroups based on the presence or absence of «dwelling paranoid» delusions, a significant difference in platelet glutamate dehydrogenase activity was noted: patients exhibiting this type of delirium demonstrated significantly higher activity levels (p=0.009). Furthermore, several notable clinical and biological correlations were established between platelet enzyme activity levels and the clinical response to psychotropic therapy. Conclusions. The significant correlations identified between platelet enzyme activity levels prior to therapy and individual clinical responses to psychotropic interventions hold potential for prognostic applications in clinical psychiatry, particularly for patients with disorders along the schizophrenia spectrum in later life.