Family Mental Health History Linked to Repeated Electroconvulsive Therapy
Patients with major depressive disorder who receive electroconvulsive therapy are significantly more likely to have a parental history of severe mental disorders than those who do not undergo the treatment, according to a nationwide register-based cohort study published in the Journal of Affective Disorders.
The study analyzed 34,890 patients in Denmark with a mean age of 45.7 years, of whom 58.5% were women. Researchers compared 5,870 patients who initiated electroconvulsive therapy against 29,020 age- and sex-matched control patients with major depressive disorder who did not receive the treatment. Individuals diagnosed with bipolar disorder or non-affective psychotic disorders at the time of their first session were excluded from the analysis.
Familial severe mental disorders drive treatment differences
Familial severe mental disorders appeared in 27.3% of patients who received electroconvulsive therapy, compared with 24.3% of the control group, yielding a risk difference of 3.0 percentage points. A parental history specifically drove this difference, appearing in 17.7% of the treatment group versus 14.1% of comparators. This divergence stemmed largely from rates of bipolar disorder at 6.4% versus 4.3% and major depressive disorder at 12.3% versus 9.8%. Non-affective psychotic disorders showed no significant disparity between the two groups at 3.6% versus 3.1%.
Among patients who received the treatment, a family history of severe mental disorders was linked to an increased rate of starting a new series two to five years later, with an adjusted hazard ratio of 1.39. However, this family history showed no significant association with initiating another treatment series within the first two years following the initial session.
Patients display similar patterns prior to therapy
Prior to their first electroconvulsive therapy session, patients with and without a family history displayed similar patterns in medication use, treatment resistance, and suicidal behavior. Treatment resistance was defined by researchers as the administration of three or more consecutive antidepressant treatments during the preceding five years.
Patients with a familial history showed a higher likelihood of having no prior psychiatric admissions during the five years leading up to treatment, at 26.5% compared to 22.0% for those without such a history. Frederikke Gronemann, PhD, of Bispebjerg-Frederiksberg Hospital in Copenhagen, led the research team.
Frequently Asked Questions
Why were patients with bipolar disorder excluded from the study?
Patients diagnosed with bipolar disorder or non-affective psychotic disorders at the time of electroconvulsive therapy were excluded; the study included only patients with major depressive disorder.
How was treatment resistance measured prior to the first session?
Investigators defined pre-treatment resistance as the administration of three or more consecutive antidepressant treatments during the five years preceding the patient’s first electroconvulsive therapy session.
What limitations did the study authors note regarding their findings?
Because the design was observational, the authors cautioned that causal conclusions were not possible and residual confounding remained a risk. The study also lacked clinical measures of treatment response and relied on data from Denmark, where clinical protocols often apply electroconvulsive therapy earlier in the treatment timeline than in other regions.
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