The effect of affective comorbidity on functioning and neurocognition in the schizophrenia spectrum

INTRODUCTION: The distinction between schizophrenia and bipolar disorder has been an ongoing debate throughout history. Current psychiatric diagnosis systems classify psychiatric disorders categorically, whereas the boundaries between these categories are not sharp, the emergence of the concept of schizoaffective disorder is a good example of this. Continuity hypothesis, spectrum concept and dimensional diagnostic approaches have been proposed in psychiatry based on current evidence obtained from genetic, biological and clinical studies. Data from classical and genetic studies show that bipolar disorder and schizophrenia share common genes. The view that schizoaffective disorder is at an intermediate point between bipolar disorder and schizophrenia supports this continuum hypothesis and overlap. Having mood disorder symptoms in patients diagnosed with schizophrenia is one of the good prognostic indicators. When we approach dimensionally in patients diagnosed with schizophrenia, very different affective components can be observed at different ends of the spectrum as mood components such as hypomania, mania melancholic type depressive and non-melancholic depressive episodes, hyperthymic temperament, faint hypomanic findings, but studies on the effects of these periods on prognosis, functionality and cognitive processes are insufficient. One aim of this study is to try to find the effect of differences in affective components on cognitive processes and functionality in patients with schizophrenia spectrum in the light of a dimensional approach. The prognosis of patients with schizoaffective disorder differed according to the predominance of affective symptoms (good course and outcome) or the predominance of schizophrenic symptoms (bad course and outcome). The small number of studies evaluating the cognitive functions of schizoaffective patients, the fact that some studies have similar features to schizophrenia and some studies to mood disorders make it difficult to understand this subject adequately. Differences between subtypes of schizoaffective disorder may obscure the results of comparative studies and may cloud efforts to understand the relationship between this disorder and schizophrenia or bipolar disorder. Cognitive heterogeneity seen in schizoaffective disorder is also observed within the depressive subtype of schizoaffective disorder itself. Bipolar type shows better cognitive functioning than the depressive type in terms of cognitive functions, but there is heterogeneity in cognitive functionalities between the subgroups called depressive type with depressive type with melancholic features and those with depressive features without melancholic features. One of the aims of this study is to determine the effect of these subtypes on cognitive functions, thus prognosis and functionality. METHODS: 137 participants, aged 18-65, literate, diagnosed with schizoaffective disorder and schizophrenia according to DSM-5, admitted to the adult psychiatry outpatient clinic at screening phase Bipolar Disorder Spectrum Diagnostic Scale, Hypomania Check List, Sydney Melancholy Prototype Index, TEMPS-A Temperament Scale self- assessment scales were applied. Self-report scales were administered to 31 healthy participants. The main study group included patients with a diagnosis of Schizoaffective disorder, a diagnosis of schizophrenia with clinically manic/hypomanic/hyperthymic/mild hypomanic findings or marked depressive features, and patients with schizophrenia with an affective co-morbidity defined after interviewing with patients who exceeded the threshold value in the screening evaluation. A total of 164 persons with a diagnosis of 137 patients were recruited. Among the patients who did not have any affective findings at the screening interview, 30 healthy controls were included in the study. In the clinical interview phase, the clinical interview consisting of Case report form, SAPS, BNSS, Sydney Melancholy Prototype Index clinician form, HDRS, YMRS, Personal and social performance scale, bipolar disorder symptom scale, and premorbid compliance scale was administered by the researcher. In addition, SCIP, Stroop test, Trail Making Test A/B, Pebl Continous Performance Test (pebl Continuous Performance Test) were applied within the scope of neuropsychological test to evaluate neurocognitive functions and DEU SCAN LAB Social Cognition Battery was applied to evaluate social cognitive functions. In addition, the Thought and Language Scale was administered by taking a voice recording to evaluate thought and language disorders. Results: Lifetime melancholia score was associated with milder negative symptoms and signs and milder structural thought disorder (especially negative thought disorder). Regardless of the diagnosis, a positive correlation was found between pre-disease functionality, individual and social functionality and melancholy score. In addition; Regardless of the diagnosis, high melancholia score indicates better performance in some neurocognitive domains (visual and motor processing, maintaining attention, SCIP total score). When the relationship between social cognition and melancholia was examined, a positive correlation was found between the melancholy score and the 'Social Knowledge' dimension, regardless of the diagnosis. Positive correlation between high melancholia score and SCIP 'consonant repetition test' performance (associated with working memory) in the Schizophrenia Group. positive relationship was found. In the Schizophrenia Group, the group with a history of melancholic depression was found to have lower Stroop-1 test scores (associated with focused attention), ie better neurocognitive performance, than the group without a history of melancholic depression. The diagnosis significantly affected the Track Making Test- B performance; It was found that the schizophrenic group with a history of depression with melancholic features had significantly lower Trail Making Test-B scores, that is, their performance in neurocognitive areas such as focused attention and information processing speed, compared to the group with a history of schizophrenic melancholic depression. Lifetime mania score was associated with milder negative symptoms and signs and milder structural thought disorder (especially negative thought disorder). When the findings are examined in terms of neurocognitive functions; It was found that regardless of the diagnosis, the history of mania may have caused a minimal effect on working memory impairment. This finding is also supported by the negative relationship between M-total score and working memory (SCIP Consonant repetition test). The SCIP 'Consonant repetition test' performance (related to working memory) of the participants who did not meet the criteria for mania and hypomania but showed weak symptoms of mania (the mania risk group) varied according to which main diagnosis group they were in; The group with weak mania symptoms diagnosed with schizophrenia showed higher SCIP 'Consonant repetition test' performance (associated with working memory) than the group without weak mania symptoms diagnosed with schizophrenia. In addition, a negative correlation was found between mania score and Tracking Test B (associated with focused attention and information processing speed) in the Schizophrenia Group. When evaluated in terms of social cognition; Regardless of the diagnosis, it was found that as the patients' mania score increased, social cognition performed better in the 'social knowledge' dimension. No significant correlation was found between the mania score and other social cognition tests. Regardless of the diagnosis, the group with weak manic symptoms (the mania risk group) performed better in terms of the 'social knowledge' dimension of social cognition, supporting our hypothesis. In core neurocognitive domains, the Schizophrenia Group scored higher, i.e., performed worse, in terms of sustained performance test 'processing error', while the Schizoaffective Disorder Group performed worse in terms of 'response inhibition'. Similar performance was found in other neurocognitive tests (Stroop1-2, Tracing, CBT (error of omission and sensitivity)). In terms of social cognition, the schizoaffective disorder group performed better in the 'mind reading test from the eyes', which is a test related to the theory of mind. In terms of facial emotion recognition, 'recognition of anger emotion', the schizophrenia group and those with a history of melancholy in the schizophrenia group performed better. When the 'total positive internal' mean scores of the Internal, Personal and Situational Attributions Test related to the attribution style were examined, a statistically significant difference was found between the groups in favor of the Schizoaffective Disorder Group. Groups performed similarly in other areas of social cognition. Conclusion: Detection of a negative relationship between melancholy score and prognostic significance; negative symptoms and structural thought disorder, positive effects of melancholy on functionality and some neurocognitive areas and social cognition areas indicate that a history of melancholic depression may be a positive prognostic factor in schizophrenia. Lifetime mania score was associated with fewer areas. The mania score was associated with milder negative symptoms and signs and milder structural thought disorder (especially negative thought disorder). When the findings are examined in terms of neurocognitive functions; It was found that regardless of the diagnosis, the history of mania may have caused a minimal effect on working memory impairment. It was found that the schizophrenia mania risk group performed better than the group without schizophrenia mania risk in terms of working memory, focused attention and information processing speed. Weak manic symptoms were found to be associated with 'social knowledge' in terms of social cognition. Our study may be a pioneering study that examines the history of melancholic depression, weak manic symptoms and mania (very different affective features) in the schizophrenia spectrum in terms of functionality-neurocognition-social cognition, accompanied by a dimensional and categorical approach. More work is needed on this subject. Keywords: Melancholy score, Mania score, Mania story group, Melancholia story group, Schizoaffective Disorder Group, Schizophrenia Group, Neurocognition, Social cognition, Pre-disease functionality, Individual and Social functionality