Oxytocin: The ‘Empathy Drug’?
Have you ever hugged a friend, held a baby, or cuddled with a romantic partner? If your answer is yes, chances are, you have experienced the effects of oxytocin, otherwise famously known as the ‘love drug.’ It is not difficult to see how this hormone got its nickname – when released in the body, oxytocin promotes feelings of attraction, empathy, and trust, all of which are important for establishing and maintaining positive social relationships.
For individuals with antisocial personality disorder (ASPD), though, it is difficult to initiate, let alone sustain, positive social relationships because of their propensity for impulsive, aggressive, and remorseless behaviour. However, when these individuals are also diagnosed with psychopathy (ASPD+P), they demonstrate even greater deficits in empathic processing, especially when it comes to recognizing and responding appropriately to another person’s fear, pain, or distress. When combined with impulsive aggression and a disregard for others’ well-being, such inability to empathize can have immense societal costs, with a disproportionate number of violent crimes being committed by individuals with ASPD.
Despite the problems associated with ASPD, there is currently no effective medication approved to treat this condition. So, given oxytocin’s role in social functioning, could this ‘love drug’ help improve empathic processing in violent offenders with ASPD and psychopathy? Understanding the individual and large-scale benefits that could arise from helping this population, John Tully, Ph.D., and his colleagues sought to answer this question with their recent study.
The researchers recruited healthy non-offenders, violent offenders with ASPD but no psychopathy (ASPD-P), and violent offenders with ASPD+P. Subjects received either oxytocin or a placebo and underwent functional magnetic resonance imaging (fMRI), which uses strong magnetic fields to detect and estimate brain activity based on changes in blood flow in the brain. During the scan, subjects were shown pictures of male and female faces with happy or fearful expressions of varying intensities and asked to identify the sex of the face presented. This task allows researchers to measure an individual’s unconscious response to another person’s emotions. In healthy individuals, increases in the intensity of fearful expressions are expected to generate stronger emotional responses, and thus greater activity in specific brain regions involved in the processing of fearful facial expressions, such as the mid-cingulate cortex.
The study found that in all task conditions, an increase in fearful expression intensity led to elevated mid-cingulate cortex activity in healthy non-offenders. Under placebo conditions, increases in fearful expression intensity led to less change in mid-cingulate cortex activity among offenders with ASPD+P than those with ASPD-P. However, when offenders with ASPD+P were given oxytocin, they demonstrated not only similar changes in mid-cingulate cortex activity to oxytocin-treated offenders with ASPD-P, but also greater changes in mid-cingulate cortex and insula (another region involved in emotion, particularly fear) activity than placebo-treated offenders with ASPD+P.
Together, these findings suggest for the first time that the emotional processing deficits associated with ASPD+P can be improved with a chemical affecting the nervous system. Given the substantial personal and social costs of this disorder, this finding has major implications for the well-being of individuals with ASPD and society as a whole.
Original article:
Tully, J., Sethi, A., Griem, J. et al. Oxytocin normalizes the implicit processing of fearful faces in psychopathy: a randomized crossover study using fMRI. Nat. Mental Health 1, 420–427 (2023). https://doi.org/10.1038/s44220-023-00067-3