German researchers have found additional evidence that the stress hormone cortisol can have positive effects in certain situations. Although chronic stress, which brings long-term elevations of cortisol in the bloodstream, can weaken the immune system and induce depression, this new study adds to mounting evidence that cortisol given near in time to a physical or psychological stress may lessen the stressor's emotional impact.

Psychologists are especially interested in what this means for preventing and treating post-traumatic stress disorder. The findings appear in the February issue of Behavioral Neuroscience, which is published by the American Psychological Association (APA).

Psychologists Serkan Het, MSc, and Oliver Wolf, PhD, of the University of Bielefeld, enlisted 44 healthy women for a double-blind study, in which neither researchers or participants knew the condition to which the women were assigned. One hour before a psychosocial stress test, participants were given either a 30 mg. dose of oral cortisol or a placebo. That 30 mg. dose is considered high, translating to a severe stressor. Experimenters tracked participant mood through self report, and measured their cortisol levels with a simple swab check of their saliva, before and after the psychosocial stress test.

Participants were asked to give five-minute oral presentations as if interviewing for their dream job, focusing on their personal strengths and weaknesses. For the next five minutes, they had to count backwards by 17s from a very high number; every time they made a mistake, they had to start over. During both tasks, participants faced a "committee" of one man and one woman, both of whom acted cold and reserved without actually being unfriendly or rude. To heighten discomfort over being evaluated, participants spoke into microphones and knew they were being videotaped.

Het and Wolf measured mood five times using two self-report questionnaires, 15 and 45 minutes participants arrived at the lab, and 1, 45, and 60 minutes after the stress test. Afterwards, the cortisol-treated women developed, on average, less negative mood states as a result of the stress-producing activity when compared with placebo-treated women. The high dose of cortisol seems to have worked as a buffer.

Wolf says that whereas chronically elevated cortisol levels can be damaging to both mood and immunity, a short spike in cortisol levels may be protective. He comments, "The difference between acute cortisol elevations and chronic cortisol hyperactivity appears to be important."

Prior research has suggested that low-dose treatment with cortisol can offer relief from the core symptoms of post-traumatic stress disorder. In addition, in patients with social phobia exposed to a social stress situation, pre-treatment with cortisol has reduced anxiety. This new study in healthy participants adds to the growing body of evidence that cortisol may be a useful clinical tool. Says Wolf, "Our study suggests that when it comes to the negative effects of stress on the emotions, an anticipatory rise in cortisol levels prior to a stressor might help someone to cope with the stressor more efficiently. This might have implications for treating and preventing post-traumatic stress and other anxiety disorders."