Cognitive impairment in depression: a systematic review and meta-analysis

P.L. Rock*, J.P. Roiser, W.J. Riedel, A.D. Blackwell

*Corresponding author for this work

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Abstract

Background. This review aimed to address the question of whether cognitive impairment should be considered a core feature of depression that may be a valuable target for treatment. Method. We conducted a systematic review and meta-analysis of cognitive function, assessed with a single neuropsychological test battery, the Cambridge Neuropsychological Test Automated Battery (CANTAB), in patients with depression during symptomatic and remitted states. Inclusion of studies comparing patients remitted from depression and controls enabled us to investigate whether cognitive impairment persists beyond episodes of low mood in depression. Results. Our meta-analysis revealed significant moderate cognitive deficits in executive function, memory and attention in patients with depression relative to controls (Cohen's d effect sizes ranging from -0.34 to -0.65). Significant moderate deficits in executive function and attention (Cohen's d ranging from -0.52 to -0.61) and non-significant small/moderate deficits in memory (Cohen's d ranging from -0.22 to -0.54) were found to persist in patients whose depressive symptoms had remitted, indicating that cognitive impairment occurs separately from episodes of low mood in depression. Conclusions. Both low mood and cognitive impairment are associated with poor psychosocial functioning. Therefore, we argue that remediation of cognitive impairment and alleviation of depressive symptoms each play an important role in improving outcome for patients with depression. In conclusion, this systematic review and meta-analysis demonstrates that cognitive impairment represents a core feature of depression that cannot be considered an epiphenomenon that is entirely secondary to symptoms of low mood and that may be a valuable target for future interventions.
Original languageEnglish
Pages (from-to)2029-2040
Number of pages12
JournalPsychological Medicine
Volume44
Issue number10
DOIs
Publication statusPublished - Jul 2014

Keywords

  • Attention
  • CANTAB
  • cognition
  • depression
  • executive function
  • memory
  • LATE-LIFE DEPRESSION
  • MAJOR DEPRESSION
  • UNIPOLAR DEPRESSION
  • NEUROCOGNITIVE IMPAIRMENT
  • AFFECTIVE-DISORDERS
  • EXECUTIVE FUNCTION
  • BIPOLAR DISORDER
  • NEUROPSYCHOLOGICAL IMPAIRMENTS
  • NONMELANCHOLIC DEPRESSION
  • 1ST-DEGREE RELATIVES

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