Baseline working memory was associated with improvement in psychological quality of life in patients with persistent...

Cognitive dysfunction is prevalent in patients with depressive symptoms and contributes to impaired quality of life (QOL) and functional outcomes. However, the prognostic significance of specific cognitive domains for long-term outcomes remains unclear in patients with persistent depressive symptoms.

In this prospective observational study, 119 patients completed the detailed examination program in routine clinical care. Of these, 84 patients with persistent depressive symptoms provided consent for study participation and met the eligibility criteria for inclusion in the present study, including completion of the baseline assessment with the Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV). The diagnostically heterogeneous cohort included patients with major depressive disorder/dysthymia as well as bipolar and related disorders. The World Health Organization Quality of Life Instrument, Short Version (WHO-QOL-26) and the World Health Organization Disability Assessment Schedule 2.0 were assessed at baseline, three, and six months; 60 participants provided 3-month follow-up data and 50 provided 6-month follow-up data. Primary hierarchical regression analyses were exploratory and conducted using complete-case data.

At baseline, participants exhibited relatively higher verbal ability and lower processing speed compared to normative data. While no significant group-level improvement in QOL was observed over six months and functioning did not improve overall, the WHODAS 2.0 standardized total score was temporarily higher at 3 months than at baseline. In exploratory analyses of complete cases, higher baseline working memory was significantly associated with greater improvement in the psychological domain of the WHO-QOL-26 at six months (β = 0.40; ΔR² = 0.14; p < 0.01). No other cognitive domains showed such associations.

Working memory was associated with subsequent improvement in psychological well-being and may represent a candidate prognostic marker in patients with persistent depressive symptoms. Given the exploratory nature and modest sample size, these findings require replication in larger, diverse populations.