'Love hormone oxytocin' helps conquer fear better

Scientists have found that the bonding hormone called oxytocin restrains fear better.

Researchers from the University of Bonn Hospital have demonstrated in a study that oxytocin inhibits the fear center in the brain and allows fear stimuli to subside more easily. This basic research could also usher in a new era in the treatment of anxiety disorders.

It has been known for a long time that the hormone oxytocin does not just have a bonding effect in the mother-child relationship and in the case of sex partners but that it is also considered to be anxiolytic. The scientists have now been able to prove its helpful effect in overwriting fearful experiences. Study's director Prof. Hurlemann, said oxytocin actually reinforces extinction: Under its influence, the expectation of recurrent fear subsequently abates to a greater extent than without this messenger.

The team of scientists induced fear conditioning in a total of 62 healthy male subjects. In the brain scanner, using video glasses, the test subjects viewed photos, for example of human faces. For 70 percent of the images, they received a very brief, unpleasant electrical shock to the hand via electrodes. The scientists used two methods to prove that this pairing of a particular photo and pain was actually anchored in the test subjects' brains: The expectation of an electrical shock was demonstrated by increased cold sweat which was measured via skin conductivity. In addition, the brain scans prove that the fear regions in the brain were always particularly active.

Half of the test subjects received oxytocin via a nasal spray. The rest received a placebo. In the men under the influence of oxytocin, the amygdala, as the fear center in the brain, was overall far less active than in the control group, whereas fear-inhibiting regions were more stimulated. Over time, the messenger caused the fear to initially be somewhat greater but then it abated to a far greater extent than without oxytocin.

The scientists hope that anxiety patients can be helped more quickly with the aid of oxytocin and that a relapse can be better prevented. In addition, the researchers presume that the hormone likely facilitates bonding between the therapist and the patient and thus the success of the treatment.

The study is published online in the journal Biological Psychiatry.