Childhood trauma, such as sexual or physical abuse, domestic violence, neglect or parental loss, can have long-lasting consequences. Researchers are exploring the effects of early trauma on the stress-response systems that influence vulnerability to later depression. Some recent findings point to biologically distinct subtypes of depressed patients based on whether or not they experienced childhood trauma. It is thought that patients in these subtypes respond differently to different types of treatment.
Stress is a risk factor for depression in general. Within the body’s stress-response system, the stress hormone cortisol acts on the hormone corticotropin releasing factor (CRF). When CRF is injected into the brains of research animals, the animals exhibit behaviors that closely parallel symptoms of depression. In clinical studies, depressed patients show heightened levels of CRF. They also show lower than normal levels of oxytocin, the “feel-good” hormone that promotes bonding and trust. The hippocampus is a region of the brain involved in emotion and memory. A small hippocampus is a well-established sign of chronic stress. In recent studies, small hippocampus volume was observed in depressed women who had experienced childhood trauma, but not in depressed patients without a history of childhood trauma.
In a multicenter treatment trial, 686 patients with chronic depression were treated with either a form of cognitive behavioral psychotherapy or with antidepressant medication, or both. Data from the study underscores the prevalence of childhood trauma. More than a third of the sample reported parental loss before age 15; more than 40 percent physical abuse; 16 percent sexual abuse; and 10 percent neglect.
The data also demonstrated clear differences in response to treatment. For the group with no childhood trauma, the combination therapy was superior to drug therapy, and psychotherapy alone was relatively ineffective. For patients with childhood trauma, the psychotherapy alone was highly efficient; twice as effective as a drug treatment in inducing remission, and three times as effective for those reporting early parental loss. This finding reinforces other studies that point to different brain types involved in depression.
Researchers emphasize that not everybody with childhood trauma goes on to become depressed. The contribution of genetic differences and the timing of childhood adversity with relation to later depression are among other areas being examined in the hope that early-life classification of depression will help to inform treatment decisions.