Premorbid, clinical and cognitive correlates of primary negative symptoms in first-episode psychosis

Negative symptoms are a core psychopathological dimension of psychotic disorders. Previous research on primary negative symptoms (PNS) mostly focused on chronic samples. Data regarding premorbid, clinical and cognitive correlates of PNS in the early illness course are limited and inconsistent. In this study, we assessed 355 Hong Kong Chinese adult patients presenting with first-episode psychosis (FEP) to early intervention service with an aim to examine the prevalence of PNS and its relationships with premorbid adjustment, clinical and cognitive profiles. PNS was defined as the presence of clinically significant negative symptoms excluding depression, positive symptoms and extrapyramidal signs. Results showed that 14.6% of patients exhibited PNS at service entry. PNS group had poorer premorbid social functioning, lower level of insight, and worse performance in Modified Wisconsin Card Sorting and digit symbol tests than non-PNS group. Logistic regression analysis showed that premorbid social functioning and digit symbol test score were independently associated with PNS. Our findings thus indicate that PNS are frequently observed in FEP patients. Deficits in proceeding speed, alongside impaired premorbid social functioning, might be specifically related to PNS in the early illness stage.