Electroconvulsive therapy stimulus parameters: rethinking dosage.

Area of Science:

• Neuroscience
• Psychiatry
• Biophysics

Background:

• Electroconvulsive therapy (ECT) is a medical treatment most often used for patients with severe major depression or bipolar disorder that has not responded to other treatments.
• Current ECT dosing relies on summary metrics like charge and energy, with individualized rules.
• The biophysical roles of distinct electrical stimulus parameters in ECT are not fully understood or utilized.

Purpose of the Study:

• To review the parameters defining the ECT electrical stimulus and their biophysical roles.
• To highlight the limitations of current summary metrics and dosing rules.
• To advocate for a more detailed approach to ECT dosing for improved outcomes.

Main Methods:

• Review of theoretical and empirical evidence on ECT stimulus parameters.
• Analysis of the neurobiological effects of distinct stimulus parameters (e.g., pulse amplitude, shape, width, train frequency, duration, directionality, polarity).
• Examination of electrode placement in conjunction with stimulus parameters.

Main Results:

• Distinct stimulus parameters exert unique neurobiological effects crucial for ECT outcomes.
• Current summary metrics (charge, energy) do not adequately capture the impact of individual parameters.
• Manipulation of specific parameters (e.g., reduced pulse width, increased pulse number) has reduced adverse effects while maintaining efficacy.

Conclusions:

• Optimizing ECT dosing requires consideration of all distinct stimulus parameters, not just summary metrics.
• Individualizing ECT by manipulating specific parameters can improve the risk-benefit ratio.
• Future ECT devices should allow adjustment and display of all stimulus parameters, and treatment records should document them.