Treatment resistant schizophrenia (TRS) is a severe type of schizophrenia characterized by persistent psychotic symptoms, poor response to antipsychotic medications and functional deterioration. Historically, negative symptoms appeared to be considered as an important feature in schizophrenia having poor prognosis, including TRS. Yet, later generations of definitions of TRS had undermined the role of negative symptoms. The most up-to-date TRRIP consensus guideline incorporated negative symptoms as a feature in TRS, yet empirical research on the nature and patterns of negative symptoms in TRS patients remained limited.

To pay a timely revisit to this issue, Dr. Raymond Chan from the Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology and his collaborators in the University of Hong Kong, and Castle Peak Hospital Hong Kong have designed a cross-sectional study to measure negative symptoms using second-generation scales in TRS patients. They recruited 206 patients with TRS, and empirically categorized them based on CAINS-negative symptoms, self-report experiential pleasure and emotion expressivity. The functioning of different TRS clusters were compared.

Their findings showed three resultant clusters. Two clusters were having more severe CAINS-negative symptoms, yet another cluster had low CAINS-negative symptoms. Among the two negative symptoms TRS clusters, one showed low experiential pleasure, another showed low emotion expressivity. When the three clusters were validated using the BNSS and SOFAS, it was found that the negative symptoms TRS cluster with low experiential pleasure exhibited the lowest functioning in terms of SOFAS. These findings provided support for the important role of negative symptoms in TRS patients in determining their social functioning. Moreover, the findings supported the heterogeneity of negative symptoms in TRS, paving ways of applications of the CAINS and BNSS to defining TRS according to the TRRIP guideline.

The study was a joint collaboration between the Associate Prof. Simon Lui from the Department of Psychiatry, the University of Hong Kong, and Dr. Elson Lam from Castle Peak Hospital. Associate Professor Simon Lui and Dr. Raymond Chan are co-corresponding authors of this study.

This study was partly supported by the Philip K.H. Wong Foundation.

The paper was published online in Schizophrenia Research on 13 July.

Lui SSY*#, Lam EHY#, Wang LL, Leung PBM, Cheng ESL, Wong CHY, Zhan N, Wong RWK, Siu BWM, Tang DYY, Liu ACY, Chan RCK* (2024). Negative symptoms in treatment-resistant schizophrenia and its relationship with functioning. Schizophrenia Research. 270, 459-464.

LIU Chen
Institute of Psychology
Chinese Academy of Sciences
Beijing 100101, China.
E-mail: liuc@psych.ac.cn