Secondary negative symptoms across schizophrenia and bipolar disorder

Abstract

AbstractBackgroundPrimary and secondary negative symptoms (NS) are core features of schizophrenia (SCZ) and can also be observed in bipolar-disorder-I (BD-I) patients. Secondary NS, due to other clinical factors, are frequently reported in clinical practice, yet systematic investigations into these symptoms remain sparse. In this study, we characterized potential sources of secondary NS as well as the association between NS and working memory (WM) capacity within the SCZ-BD spectrum.MethodsWe included 50 outpatients with SCZ and 49 with BD-I and assessed NS domains using SANS global scores for avolition-apathy, anhedonia-asociality, alogia and blunted affect. To identify clinical factors as potential sources of NS we applied multiple regression analyses including positive symptoms, disorganization, depressive symptoms, antipsychotic and mood stabilizer intake. We quantified their relative importance as sources for secondary NS through dominance analyses. Lastly, we used multiple regression to assess the relationship between NS domains and WM.ResultsAcross SCZ and BD-I, disorganization was associated with avolition-apathy and anhedonia-asociality and depressive symptoms additionally predicted anhedonia-asociality. Antipsychotic dose was associated with blunted affect while group differences only predicted alogia. Avolition-apathy predicted impaired WM transdiagnostically and in BD-I higher anhedonia-asociality was associated with better WM capacity.ConclusionSecondary NS are prevalent across the SCZ-BD spectrum, with disorganization reflecting an important factor for avolition-apathy and anhedonia-asociality. Avolition-apathy emerged as a transdiagnostic predictor of WM impairment, while anhedonia-asociality was linked to better WM in BD-I. Altogether, these findings support the clinical relevance and need for future research of secondary NS across the SCZ-BD spectrum.