Oxytocin, often called the love hormone, may have different effects on men and women, and in certain circumstances the hormone may actually trigger anxiety, suggested a new study.

Clinical trials are testing whether oxytocin has potential as a treatment for anxiety, depression and post-traumatic stress disorder. Clinical studies have found that women with depression or PTSD have elevated oxytocin levels.

Now, the new study suggests an alternate possibility.

“Our results show that stressed females have both reduced social motivation and increased oxytocin. It’s possible that oxytocin might contribute to a depression-like syndrome in females,” said co-lead researcher Brian Trainor from the University of California-Davis.

“If correct, inhibiting oxytocin action might have unanticipated benefits,” he added.

In a series of experiments, the researchers administered doses of oxytocin with a nasal spray to male and female mice.

Consistent with previous studies, oxytocin increased the motivation for social interaction in stressed males. However, in stressed females, oxytocin had no effect.

When non-stressed females received oxytocin, social motivation was reduced. This effect of oxytocin is similar to the effect of social stress.

“Reduced social motivation can be part of a depression-like syndrome,” Trainor said.

Trainor and colleagues found important differences in how stress affected the production of oxytocin.

After stress, nerve cells in the brain produced more oxytocin in females but not in males.

Trainor said the findings have implications for studies investigating the utility of oxytocin as a therapeutic.

“Most clinical studies investigating oxytocin as a treatment for depression or anxiety include only males. It’s important to include both men and women in these studies, he said.