Can Electroconvulsive Therapy (ECT) cause long-term cognitive side effects?

Long-Term Cognitive Side Effects of Electroconvulsive Therapy (ECT)

Yes, ECT can cause long-term cognitive side effects, particularly deterioration in overall cognitive function and learning capabilities, as demonstrated by the most recent and high-quality evidence using sensitive assessment tools. 1

Evidence of Long-Term Cognitive Effects

• The most recent 2024 meta-analysis using the specialized Electroconvulsive Therapy Cognitive Assessment (ECCA) tool demonstrated significant long-term overall cognitive impairment (SMD = -0.94,95% CI [-1.33, -0.54], p < 0.00001) in patients with major depressive disorder following ECT 1

• Specifically, ECT shows adverse effects on long-term learning cognitive abilities (SMD = -0.37,95% CI [-0.55, -0.18], p < 0.0001), which persist beyond the immediate post-treatment period 1

• Previous research has underestimated these cognitive effects due to inadequate sensitivity of conventional assessment tools like MMSE or MoCA 1

Cognitive Domains Affected and Spared

• Negatively Affected Domains:

  • Overall cognitive function (significant deterioration) 1
  • Learning capabilities (significant deterioration) 1
  • Autobiographical memory (significant deficits reported) 2

• Relatively Spared Domains:

  • Memory (no significant detriments, SMD = 0.16,95% CI [-0.02,0.34], p = 0.08) 1
  • Attention (no significant detriments, SMD = 0.23,95% CI [-0.07,0.54], p = 0.14) 1
  • Language (no significant detriments, SMD = -0.10,95% CI [-0.25,0.05], p = 0.19) 1
  • Spatial perception and orientation (no significant detriments, SMD = -0.04,95% CI [-0.28,0.20], p = 0.75) 1

• Domains Showing Improvement:

  • Executive function and processing speed (significant enhancement, SMD = 0.52,95% CI [0.29,0.74], p < 0.00001) 1

Factors Influencing Cognitive Side Effects

• Electrode Placement:

  • Bilateral ECT is associated with more pronounced cognitive impairment than right unilateral placement 1
  • The shift from right unilateral to bilateral treatment in clinical practice may contribute to heterogeneity in research findings 1

• Treatment Frequency:

  • Increased frequency of ECT sessions may escalate cognitive function impairment 1
  • Standard practice of thrice-weekly sessions may have different cognitive outcomes compared to biweekly schedules 1

• Electrical Dosage:

  • Significant inverse relationship exists between electrical dosage and delays in learning and verbal information recall 1
  • Variations in dosage across studies contribute to disparities in cognitive outcomes 1

Clinical Implications and Monitoring

• The ECCA tool demonstrates superior sensitivity in detecting cognitive changes compared to conventional tools like MMSE or MoCA 1

• Informant-based cognitive assessment is crucial as patients may be unaware of or underreport memory impairments 1

• Cognitive monitoring before, during, and after ECT is essential for early detection of impairments and timely interventions 1, 3

• Patients should be informed about potential long-term effects on overall cognitive function and learning capabilities before consenting to ECT 2

• Cognitive assessment should specifically include measures of autobiographical memory, verbal fluency, and verbal memory 4

Limitations in Current Evidence

• The potential for false-positive results with the ECCA tool needs further validation 1

• Limited original studies using the ECCA tool prevent further stratification and subgroup analyses 1

• Individual variability in cognitive responses to ECT is significant and difficult to predict 3

• Most studies focus on patients with major depressive disorder, limiting generalizability to other conditions 1

While ECT remains an effective treatment for treatment-resistant depression, patients and clinicians should be aware of the potential for long-term cognitive side effects, particularly in overall cognitive function and learning capabilities, and implement appropriate monitoring strategies to detect and address these effects.