A depressed patient has a reduced chance of successful pain management.

Formal clinical trials in depressed patients have not been reported.

Additionally, an experimental study followed depressed patients for one year.

Earlier studies have reported low melatonin levels among some groups of depressed patients.

How many seriously depressed patients showed significant improvement within six months?

Only 10 to 40 percent of depressed elderly patients are given medication.

For one thing, animals respond to the drugs within half an hour, while depressed patients need weeks before feeling their effects.

But the researchers found no evidence that the depressed patients in the study somehow needed to suffer.

The team is continuing to operate on depressed patients, with a goal of 20.

Yet scientists are far from knowing exactly what such findings mean for depressed patients.