Can SSRIs cause cognitive decline?

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  • Patients with depression or obsessive-compulsive disorder (OCD) show steady cognitive decline after 8 wk of treatment with selective serotonin reuptake inhibitors (SSRIs).

Study design

  • Prospective study.
  • 50 patients (half diagnosed with depression, half diagnosed with OCD) with no history of SSRI treatment.
  • 52% of patients were prescribed paroxetine (Paxil), 28% sertraline (Zoloft), 12% fluoxetine (Prozac), and 8% citalopram (Celexa).
  • Patients completed the Mini-Mental State Examination (MMSE) at weeks 0, 3, 5, and 8.
  • Funding: Not disclosed.

Key results

  • Baseline mean MMSE score for entire cohort was 23.94.
  • MMSE scores declined steadily between weeks 3, 5, and 8 (22.1, 21.4, 20.66, respectively; overall P<.0001).  
  • No link between MMSE score and age (P=.12) or education level (P=.14).


  • Small patient sample with no long-term follow-up.
  • Effect of disease on cognitive function was not studied.

Why this matters

  • Studies on the effect of SSRIs on cognition have yielded conflicting results.