Receiving a dose of the hormone oxytocin can change the way emotions are processed in the brains of people suffering from chronic depression, offering promising potential as a treatment for the disorder, according to a study published in the journal BMC Psychiatry.

Chronic depression is a serious and often debilitating mental disorder, which is often resistant to current depression treatments. The disorder is thought to stem in many cases from early childhood trauma, and is linked with difficulties processing social emotions. When decoding others’ facial expressions, people with chronic depression are believed to focus too much attention on cues related to negative emotions, and too little attention on cues related to positive ones.

Oxytocin is a hormone known to be related to making social bonds and processing emotional information. Because of this, some psychologists have suggested that therapy with oxytocin may serve as an effective treatment for disorders related to poor social and emotional cognition by making these experiences easier to process.

A team of scientists led by Gregor Domes, of the University of Freiburg, evaluated the potential of this treatment in a controlled double-blind study of 43 patients with chronic depression. Patients were given either a dose of oxytocin administered by nasal puff or a placebo. One hour later, the patients completed a laboratory task in which they were shown images of happy, angry, or neutral faces in pairs. Reaction time to identify the location of a dot left on the screen after the faces were removed as used to infer how much cognitive attention the patients devoted to each type of face in comparison to the others. From these results, the researchers were able to determine how much initial attention was given to each, and how quickly that attention was disengaged.

The patients who received the dose of oxytocin gave significantly more cognitive attention to the happy faces, and significantly less attention to the angry faces, when compared with the chronically depressed patients receiving the placebo. Those in the oxytocin group were also slower to withdraw their attention from the happy faces. These results suggest that oxytocin administration caused patients suffering from chronic depression to process information related to social emotions in a healthier way.

The study authors conclude that oxytocin plays a role in some of the problems with emotional cognition associated with chronic depression. They suggest that deficiencies in oxytocin production and regulation may be involved in the course of this disorder. Although it will take years to translate these findings into effective treatments, oxytocin may one day hold the key for helping people who suffer from this treatment-resistant and often debilitating condition.