Hazards

Possible major hazards include:

• hazards associated with the anaesthetic
• cardiovascular abnormalities - cardiac arrhythmias
• injury to tongue, teeth, bones - less now that muscle relaxants are used (1)
• subdural haematoma (2)
• loss of memory:
  • retrograde and anterograde amnesia occur acutely though many patients are unaware of it
  • patients may continue to complain of memory loss for months - there is little evidence to support this although depression itself impairs memory

Possible minor hazards include:

• if female - possible amenorrhoea
• headaches
• burns from electrodes
• confusion transient resolves within hours

Based on the number of treatments given, it was estimated the mortality rate associated with ECT as less than 1 death per 73,440 treatments (1). The most common reported adverse events related to ECT were injury to the mouth (including dental and tongue injury).

In a retrospective cohort study (n=10,016, Ontario), there was no clinically significant increase in risk for serious medical events with ECT (0.25 vs. 0.33/person/year in exposed vs. unexposed group; HR 0.78; 95% CI 0.61-1.00) and risk of suicide was significantly reduced (p<0.03) (3)

Reference:

• Watts BV et al. An examination of mortality and other adverse events related to electroconvulsive therapy using a national adverse event report system. J ECT. 2011 Jun;27(2):105-8.
• Saha D, Bisui B, Thakurta RG, Ghoshmaulik S, Singh OP. Chronic subdural hematoma following electro-convulsive therapy. Indian Journal of Psychological Medicine. 2012;34(2):181-183
• Kaster TS et al. Risk of serious medical events in patients with depression treated with electroconvulsive therapy: a propensity score-matched, retrospective cohort study. Lancet Psychiatry (July 12th 2021).