Prolactin changes during electroconvulsive therapy: A systematic review and meta-analysis

Background: Early studies reported a prolactin surge during electroconvulsive therapy (ECT). The aim of this study is to review and meta-analyze data on ECT-related prolactin changes. Method: A systematic review and meta-analysis was conducted for trials investigating prolactin changes in ECT-treated patients using standard mean differences (SMD, 95% confidence intervals). Subgroup analyses included comparisons of ECT-related prolactin changes in women vs. men, patients receiving different anesthetics, bilateral vs. unilateral and high-vs. low-dose ECT. Results: In six trials including 109 ECT-treated patients and 74 controls, prolactin changes were larger in ECT-treated patients than in controls (SMD = 0.89, 95%CI = 0.55, 1.23, p < 0.001 and 1.03, 95%CI = 0.31, 1.75, p = 0.005 for the fixed and random-effect model respectively), despite heterogeneity in the samples (I-2 = 72%, tau(2) = 0.62). Effects were led by differences in patients premedicated with methohexital (SMD = 1.14, 95%CI = 0.7, 1.57, p < 0.001 for both fixed and random-effect model). A meta-regression reported significant age effects (coefficient estimate 2.32, 95%CI = -0.73, 3.91, p < 0.01). Additionally, prolactin changes were larger in ECT-treated women than men (SMD = 0.88, 95%CI = 0.58, 1.18, p < 0.001 and 0.99, 95%CI = 0.22, 1.75, p = 0.012 for the fixed and random effect model). Bilateral ECT-treated patients had larger increase than unilateral ECT-treated patients (SMD = -0.81, 95%CI = -1.35, -0.27, p = 0.003 and - 0.86, 95%CI = -1.46, - 0.25, p = 0.006 for the fixed and random-effect model). Comparisons between high- and low-dose ECT-treated patients could not be conducted. The quality of the studies was overall poor, with four exceptions. Discussion: Patients receiving ECT had larger prolactin increases than controls. Increases were larger in methohexital-premedicated patients, women vs. men and patients with bilateral vs. unilateral ECT.