...and aided by a shocking paradox.

When antidepressant drugs and psychotherapy fail to lift the dark veil of severe depression -- especially if suicide seems likely -- electroconvulsive therapy (ECT) becomes a treatment option. Psychiatrists generally view ECT as an effective way to pull someone out of a depression temporarily, even though the technique elicits intense controversy outside their profession.

A clear picture of the types of brain changes ECT produces to relieve depression has yet to emerge. But researchers now report that successful ECT involves a biological paradox. Several studies have found reduced blood flow in the brains of untreated depressed people, compared to healthy adults; but cerebral blood flow declines even more in people whose depression eases after ECT.

A total of 54 individuals diagnosed with major depression completed the study. Mitchell S. Nobler, a psychiatrist at Columbia University, and his coworkers tracked cerebral blood flow with sensors placed on the scalp to measure the escape of minute amounts of a radioactive substance inhaled by participants.

The 28 participants whose condition improved after a session of ECT showed drops in cerebral blood flow about 1 hour after treatment. Those who responded to ECT displayed further decreases in blood flow over the course of treatment, which averaged about nine sessions, the researchers assert in the November ARCHIVES OF GENERAL PSYCHIATRY.

Any explanation of how this effect eases depression remains speculative, Nobler's group notes. ECT's anticonvulsant properties may quell the activity of the few brain areas that become overactive during depression, they theorize (SN: 9/12/92, p.165).