Association of negative symptom domains and other clinical characteristics of schizophrenia on long-term hospitalization.

Background: Recent studies suggest five domains for negative schizophrenia symptoms: anhedonia, asociality, avolition, blunted affect, and alogia. Avolition has been considered a characteristic symptom in community-dwelling patients. However, few studies have explored the association of these symptoms with long-term hospitalization. Purpose: This study explored the relative association of each of the five domains of negative symptoms in two groups of patients with schizophrenia: long-term hospitalized and community-dwelling patients. Methods: Participants included 56 long-term inpatients and 111 community-dwelling patients at Nasukougen Hospital in Japan. The nearest neighbor matching within caliper was used. After matching participants by age, sex, disease duration, and years of education, each group was assigned 30 participants. Model 1 was analyzed with a logistic regression analysis with 5 subdomains as independent variables. Model 2 was analyzed after adding positive symptoms, cognitive function, functional skills, and functional outcomes to the subdomains that were significant in model 1. Results: The results indicated that asociality was significantly associated with long-term hospitalization. When the characteristic clinical factors of schizophrenia were added, asociality, daily living skills, and social and role functions were found to be characteristic of long-term hospitalization. Among the negative symptoms, lack of social motivation was more characteristic among the group with a poor prognosis. Conclusions: Of the negative symptoms associated with long-term hospitalization, asociality, lack of social motivation, rather than avolition was found to be most strongly associated with community-dwelling patients' functional outcomes. Further studies are required to establish a causal association as it may have therapeutic implications.