If you fell off of your bike and broke your arm, specialized sensory receptors (known as nociceptors) found in the skin, muscle, joints, bone and organs would send a signal to your brain to tell you that you’ve been injured. In response to breaking a bone, your body also has a system in place (i.e., the brain’s opioid system) that helps to reduce the sensation of pain. Naturally produced opioids that are released in the body can attach to three types of opioid receptors (i.e., mu, delta and kappa), while scientists have also developed highly potent, synthetic opioid pain medications (e.g., morphine) that can mimic the effects of naturally occurring painkillers to provide pain relief.
Bonding vs. rejection
Researchers have increasingly recognized that the brain’s opioid system is not only important for the management of physical pain; it also plays a role in social rejection, social bonding and other aspects of our interpersonal relationships. Feeling close to others and having close relationships are important elements for human survival. The brain opioid theory of social attachment suggests that different aspects of our social behavior and interactions are influenced by the endogenous opioid system (particularly mu-opioids) that are released by our positive, pleasant experiences of social bonding, while social rejection or loss can lead to feelings of disconnection and separation distress due to reduced opioid activity in the brain.
Unintended consequences of taking naltrexone on relationships
Aside from a person’s heightened vulnerability to dependence when taking opioid pain medications, it appears that opioid painkillers may have unintentional consequences on our ability to feel close and connected to others. The effect of opioids on social bonding was recently examined in humans by Tristen K. Inagaki, Ph.D., a professor at the University of Pittsburgh, and her colleagues, who found that naltrexone, an opioid antagonist used to treat opioid use disorders and alcohol use disorder, reduced feelings of social connection among participants compared to the placebo.
Thirty-one participants took naltrexone and a placebo, each for four days with a 10-day separation in between. While taking naltrexone and the placebo, the participants recorded their day-to-day feelings of social connection (i.e., how disconnected they felt) and general positive affect (i.e., positive experiences or mood). They also engaged in a laboratory-based social connection task, during which they read positive messages written from close friends and family members, and then rated their feelings of connectedness and feelings of positive affect. The results indicated that participants taking naltrexone exhibited reduced feelings of social connection and lower overall positive affect compared to when participants were taking the placebo.
In support of the brain opioid theory of attachment, Dr. Inagaki’s and her colleagues’ findings suggested that the use of opioid antagonists such as naltrexone may affect a person’s subjective experience of rewarding social experiences. In particular, the researchers suggested that the opioid system may play a particularly important role in social experiences of bonding and affiliation.
The importance of relationships
Social relationships and bonds with others are especially important for people in treatment and recovery from alcohol or opioid addiction. As such, this novel study introduces a limitation of naltrexone in its ability to provide long-term treatment, as it may have unintended consequences on the ability to feel connected to others.
Sovereign Health of Rancho San Diego provides adolescents from 12 to 17 with behavioral health treatment services for substance use disorders, such as alcohol use disorder and opioid use disorder. In addition, our evidence-based, individualized treatment programs are offered to adolescents with mental health and co-occurring disorders. For more information about the treatment programs at our Rancho San Diego facility, please contact our 24/7 helpline for further assistance.
About the author
Amanda Habermann is a writer for Sovereign Health. A graduate of California Lutheran University, she received her M.S. in clinical psychology with an emphasis in psychiatric rehabilitation. She brings to the team her background in research, testing and assessment, diagnosis and recovery techniques. For more information and other inquiries about this article, contact the author at firstname.lastname@example.org.