Journal of International Psychiatry

【Abstract】Objective Cross-diagnostic cluster analysis was used to reveal the intra-group heterogeneity of cognitive impairment in schizoaffective spectrum disorder and bipolar disorder. Methods In this study, 264 subjects were enrolled: 117 healthy controls, 55 bipolar I, 56 bipolar II, and 36 schizophrenic spectrum disorders. Neurological/social cognitive function, anxiety, depression, mania, and psychotic symptoms were assessed for all subjects. After converting the cognitive function score into Z score, hierarchical cluster analysis was performed to detect the cognitive subtypes and compare the symptom differences among different cognitive subtypes. Results Three cognitive subtypes were identified by hierarchical cluster analysis: subtype 1 was mild cognitive impairment, subtype 2 was moderate cognitive impairment, and subtype 3 was severe cognitive impairment. Among the three subtypes, the proportion of diseases (schizophrenia, bipolar I, and II) was statistically significant (X2=20.412, P<0.0001). Subtype 1 accounted for the smallest split spectrum, and bipolar II accounted for the largest proportion. The proportion of diphasic type I and II in subtype 2 was similar, and both were more than split lineages. Subtype 3 had the largest proportion of split lineages, and biphasic type II had the smallest proportion. The psychotic symptoms of subtype 3 were more severe than those of subtype 1 (P=0.03) and subtype 2 (P=0.03). Subtype 1 (P=0.09, significant margin) and subtype 2 (P=0.05, significant margin) had more anxiety symptoms than subtype 3. Conclusion The psychotic symptoms were more severe in the subtypes with severe cognitive impairment. Patients with mild and moderate cognitive impairment had more severe anxiety symptoms. Schizoaffective disorder and bipolar disorder are a "continuous spectrum" in terms of the severity of cognitive impairment: patients with bipolar II tend to have mild or moderate cognitive impairment; patients with bipolar I tend to have moderate impairment; and patients with schizoaffective spectrum tend to have more severe cognitive impairment. Hierarchical cluster analysis across diagnosis can help to reveal the heterogeneity of cognitive impairment and clinical symptoms of severe mental disorders.

Schizophrenia; Bipolar disorder; Cognitive function; Hierarchical clustering