For years researchers have debated the relationship between PTSD and depression: are PTSD patients actually depressed, or are their depression-like symptoms further evidence of PTSD? Both disorders can result in trouble concentrating, for example, or difficulty sleeping, or the loss of feelings of pleasure.

In the August issue of the Journal of Nervous and Mental Disease, two Brown-affiliated scientists reported research indicating that the two disorders do indeed co-occur in people exposed to serious traumas. Laurel Franklin, a psychologist and postdoctoral research fellow at Rhode Island Hospital, and Mark Zimmerman, associate professor of psychiatry, compared psychiatric outpatients diagnosed with PTSD alone to patients diagnosed with PTSD and major depression. The researchers found that patients with PTSD alone were just as likely as depressed patients to experience the three overlapping symptoms affecting concentration, sleeping, and pleasure.

The next step, Franklin says, is to figure out why PTSD sufferers are so likely to become depressed. "It could be that the depression is a reaction to a traumatic event," she says, "or it could be that people with PTSD become depressed after years of having to cope with chronic post-traumatic stress."