Well-established indications: Catatonia, major depressive disorder (MDD) (particularly psychotic depression), mania, acute psychosis. Medical intolerability to alternative treatment, patient request, and previous ECT responders are also considered first-line indications.

Possible indications: Delirium, obsessive-compulsive disorder (OCD), seizure, and Parkinson disease.

Not likely effective in: Somatization disorder, personality disorders, anxiety disorders (other than OCD), chronic status of schizophrenia.

Absolute contraindications: None.

Relative contraindications: Cardiovascular conditions, space-occupying intracranial lesions, cerebral aneurysms, recent strokes.

Unilateral at the nondominant side.

Medically refractory epilepsy.

Treatment-resistant depression.

Quick screening test: Acholest paper test.

Confirmation: Serum pseudocholinesterase activity.

Genotype: Allele-specific polymerase chain reaction, available only in advanced research laboratories.

Genetic consultation.

Thalamus for essential tremor and multiple sclerosis.

Globus pallidus or subthalamus for Parkinson disease.

Muscle soreness due to fasciculation.

Increased extracellular potassium due to depolarization of the neuromuscular junction.

Prolonged apnea, particularly in patients with pseudocholinesterase deficiency.

Conservative and less destructive.

Easier surgery.

Safer and fewer side effects.

Adjustable dosage.

Preserves the potential for future treatment with more advanced techniques, such as brain cell transplantation.