Cognitive Symptoms and Overall Functioning During Major Depressive Episodes: Correlation Analysis of Patients With Unipolar and Bipolar Disorders

Aim: This cross-sectional observational study was designed to characterize global functioning in patients with unipolar depression (UD) and bipolar depression (BD), focusing on the relationship between functional impairment and objectively assessed and subjectively perceived cognitive deficits, as well as to potential domain-specific cognitive–functional patterns across diagnostic groups. Methods: Individuals experiencing a major depressive episode (MDE) in the context of major depressive or bipolar disorder were recruited. Global functioning was assessed with the Functional Assessment Short Test (FAST), objective cognition with the Screen for Cognitive Impairment in Psychiatry (SCIP), and subjective cognition with the Perceived Deficits Questionnaire–Depression–5-item (PDQ-D-5). Group differences were analyzed using χ2 tests and ANCOVA, adjusting for illness duration and age at onset. Associations between cognitive measures and global functioning were examined using Pearson’s correlations. Results: A total of 102 patients were recruited: 54 with UD, 48 with BD. Clinically relevant functional impairment was observed in 87% of UD patients and 93.7% of BD patients. BD individuals showed greater global functional impairment than UD patients, with higher FAST total scores (44.5 ± 23.1 vs. 33.5 ± 14.6, p = 0.006) and worse functioning across most domains. Global functioning was strongly associated with subjectively perceived cognitive difficulties in both UD (ρ = 0.609, p < 0.001) and BD (ρ = 0.475, p < 0.001), whereas no significant associations were found with objective cognitive performance. Domain-specific analyses revealed different patterns of association, with attention and organization related to functioning in UD and retrospective memory in BD. Conclusion: MDEs in unipolar and bipolar disorders are associated with marked functional impairment. Perceived cognitive difficulties may impact daily functioning more than objectively assessed deficits, highlighting their clinical relevance. The distinct cognitive–functional profiles in UD and BD patients underscore the importance of domain-specific assessments to guide interventions targeting both symptom remission and functional recovery.