Affective and non-affective cognition in patients with bipolar disorder type I and type II in full or partial remission: Associations with familial risk

BACKGROUND: The upcoming conversion of the ICD-11 will subdivide patients with bipolar disorder (BD) into BD type I (BD-I) and BD type II (BD-II). This study aimed to investigate whether cognitive impairments could aid as objective cognitive biomarkers for recently diagnosed BD subtypes by comparing cognitive profiles between BD subtypes, their unaffected relatives (UR), and healthy controls (HC).

METHODS: The sample included 76 patients with BD-I, 149 patients with BD-II, 28 UR of patients with BD-I (UR-I), 50 UR of patients with BD-II (UR-II) and 168 HC from the Bipolar Illness Onset study, who were assessed with an extensive non-affective and affective cognitive test battery.

RESULTS: The results showed no significant differences in affective or non-affective cognition between BD-I and BD-II. Compared to HC, patients with BD-I (but not BD-II) showed worse performance in verbal fluency (p = .01) and were slower at recognising fearful faces (p = .045), while patients with BD-II (but not BD-I) displayed generally poorer recognition of facial expressions (p = .02). Only UR-I showed lower performance on verbal fluency (p = .049) and aberrant affective cognition (ps≤.047) compared to HC.

LIMITATIONS: The potential confounding effects of medication were not explored.

CONCLUSIONS: The lack of significant differences in cognitive profiles between recently diagnosed BD-I and BD-II suggests that neither affective nor non-affective cognition are indicative of BD subtype.