Peculiarities of psychoacoustics as a differential diagnostic criteria of schizoaffective disorder and paranoid schizophrenia at the early stages of development

Abstract

The work carried out the assessment of interconnection between the presence of musical ear and defective manifestations in patients with paranoid schizophrenia and schizoaffective disorder (SAD). SAD remained one of the most uncertain mental disorders. The certain variability and instability in the diagnostic interpretation of this nosology, the fuzziness of the criterion assessment greatly affected the quality of diagnosis and differential diagnosis, especially in the early stages of development of mental disorders of this spectrum (affectively-paranoid). The aim of the study was to compare the peculiarities of psychoacoustics (namely the presence/absence of musical ear) in patients with the SAD diagnosis and in patients with paranoid schizophrenia (PS), as well as the degree of severity of negative symptoms. In our research we conducted comparative evaluation of negatives symptoms in 40 patients with paranoid schizophrenia and 40 patients with schizoaffective disorder by means of NSA-16 scale and PANSS negative symptoms subscale. Comparison of difference probability between indexes of research groups is done by means of chi-squared and Mann-Whitney tests. In the group of patients with schizoaffective disorder, most persons had musical ear, the rates of negative symptoms were significantly lower than in patients with paranoid schizophrenia, who did not have developed musical ear. Thus, the average assessment of negative symptoms according to the scale of NSA-16 in the group of patients with a diagnosis of paranoid schizophrenia was 4.89±0,10, which by 2.6 (р<0,01) higher than in the group of patients diagnosed with schizoaffective disorder – 1,84±0,10. In both groups, the highest average rates of negative symptoms were inherent to the symptoms “Sexual attraction” and “Limited purposefulness”. The average assessment of the key points of evaluation in the group of patients with PS, by 2,77 (р<0,01) higher than in the group of patients with SAD — 4,74±0,11 against 1,71±0,08, according to the analysis of the subscale of negative symptoms of the PANSS. The violation of spontaneity and fluidity of speech occupied one of the leading places among all the negative symptoms of this scale in both groups of patients. So, the dependence between the factor of presence or absence of musical ear and the degree of severity of negative symptoms of schizophrenia and schizoaffective disorder was established, which allowed to confirm the expediency of evaluating musical abilities in such patients for the expansion of prognostic and diagnostic possibilities in psychiatric practice.