For depressed older adults who do not respond to an adequate dose of an antidepressant drug -- or respond but relapse -- adding a second antidepressant may improve their recovery, a new study shows.

"Overall, my view is that our findings help to expand the range of strategies that can be used to treat the older adult who has depression," study leader Dr. Mary Amanda Dew from the University of Pittsburgh told Reuters Health.

"Adding a second antidepressant to first-line therapy is not for all older adults whose depression has not improved, but it can be effective for those individuals who are medically able to take a second antidepressant," she added.

Dew and her colleagues monitored depression levels during initial treatment with paroxetine (known by the brand name Paxil) and psychotherapy in 195 adults aged 70 or older with major depression. A total of 77 had an inadequate response to initial therapy, 28 responded but experienced early relapse, and 90 responded without relapse, the investigators report in the American Journal of Psychiatry.

Of the 105 patients offered a second antidepressant, 69 took the additional medication and 36 did not.

The team found half of the patients who did not respond to initial treatment and two-thirds of the patients who relapsed after initial treatment responded to augmentation therapy.

"While recovery rates of those receiving augmentation are not as high as in those who responded to first-line therapy, the recovery rates are still high enough to suggest that augmentation should be tried when older adults' depression is not improving," Dew said.

She noted that doctors are often hesitant to add more medications to what older patients are already taking, "but our findings suggest that some older adults may only recover if they receive a combination of antidepressants."

The risks of adding another antidepressant should be weighed against the substantial risks in living with ongoing depression -- including poor quality of life and suicide, Dew commented.