Impact of Primary Negative Symptoms on Functional Outcomes in Schizophrenia

Objective: Negative symptoms are known to undermine functional outcomes in people with schizophrenia; however, most studies have not accounted for whether these symptoms were primary or secondary to other psychopathological factors. The present study examined the impact of primary negative symptoms on functional outcomes in patients with schizophrenia.

Method: The sample included 1427 patients with schizophrenia who completed the baseline visit in the CATIE study. Symptoms were assessed with the Positive and Negative Syndrome Scale and Calgary Depression Scale, extrapyramidal side effects with the Simpson-Angus scale, and functional status with the Heinrichs-Carpenter Quality of Life Scale.

Results: Negative symptoms were significantly and inversely related to each domain of functioning examined. These relationships remained after statistically controlling for the influence of potential sources of secondary negative symptoms. In addition, the relationships between negative symptoms and specific domains of functioning remained in patients who had mild/absent positive, depressive, anxiety and extrapyramidal symptoms. Negative symptoms were associated with functional outcomes even in antipsychotic-free patients.

Conclusions: Primary negative symptoms significantly contribute to the functional impairment seen in people with schizophrenia. A better understanding of the etiology and pathobiology of these symptoms is required to guide the search for effective therapeutics that promote functional recovery.