Negative symptoms are main predictive factors of schizophrenia disability and seriously affect the social function and quality of life of patients with schizophrenia. Therefore, the development and validation of negative symptoms of schizophrenia is one of the prioritized areas for schizophrenia research. Recent theoretical and clinical findings suggest that negative symptoms can converge into two factors, namely the “motivation-anheodnia” and the “expression”. The Clinical Assessment Interview for Negative Symptoms (CAINS) was developed in accordance with this theoretical framework and has been validated with good psychometrics traits in Caucasian samples. However, very little is known about the clinical utility of the CAINS in the Chinese settings. Negative symptoms are present and varied in different stages of schizophrenia. Discriminant validity of the CAINS in different stages of schizophrenia is worthy of investigating. However, it is still unclear whether patients with schizophrenia could be effectively categorized by CAINS. The present dissertation aimed to examine the reliability and validity of the Chinese version of CAINS in schizophrenia spectrum disorders.
Study 1 aimed to examine psychometrics traits of the Chinese version of the CAINS. One hundred and eighty-five patients with schizophrenia were recruited. The findings showed a stable two-factor structure, namely “notivation-pleasrue” and “expression”. Significant correlations were also found between these two factor subscores with negative sympotms captured by the conventional clinical ratings as well as the self-reported experience of pleasure. The Chinese version demonstrated impressive psychometric properties in terms of Cronbach alpha coefficients, test-retest reliability, and interrater reliability.
Study 2 aimed to explore the discrimination of the CAINS in 44 patients with schizophrenia, 43 non-psychotic first-degree relatives, 37 at-risk individulas with schizotypy from 44 healthy controls.. People with schizophrenia exhibited significantly higher CAINS subscale scores than first-degree relatives and controls. In addition, first-degree relatives had higher “motivation/pleasure” scores than controls. The “motivation/pleasure” subscale scores of individuals with social anhedonia were also significantly higher than healthy controls.
Study 3 adopted cluster analysis of the CAINS factor scores to examine whether CAINS factor scores could successfully classify schizophrenia patients into different subtypes based on their negative symptom manifestations. The results suggested a 2-cluster solution comprising a amotivation-anhedonia group (n = 38) and a group of without negative symptom manifestations (n = 74). Validaiton of the cluster solution showed that schizophrenia patients with amotivation-anhedonia showed more deficits in negative symptoms, experiential pleaure ability as well as depressive sympotms than those without negative sympotms deficits and healthy controls..
Taken together, the present findings suggested that the Chinese version of the CAINS demonstrated a robust two-factor structure of “amotivation-anhedonia” and “expression” factors of negative symptoms in schizophrenia. Impressive reliability and validity of the Chinese version of the CAINS was also demonstrated. The present study also showed the sensitivity of the CAINS factor scores to discriminate patients with schizophrenia, non-psychotic first-degree relatives, at-risk individuals with schizotypy from healthy controls. The use of the CAINS score could also effectively classify subytpes of schizophrenia patients with specific amotivation and anhedonia from those with general negative sympotms manifestations. These all support the Chinese version of the CAINS is an effective and valid clinical tool for assessing negative symptoms for schizophrenia in the Chinese setting.