There is new research, just published in the journal Molecular Psychiatry and reported on Science Daily, that should be of interest to people who treat addictions, as well as people and families in recovery. It offers insight into one of the ways that co-existing disorders, such as depression, may complicate recovery from addiction.
The new study was done in an effort to determine whether the brains of depressed people respond differently to the experience of social rejection than the brains of non-depressed people. It turns out that they do, and since rejection-sensitivity is thought to be a risk factor for addiction and relapse, the fact that some brains have unique responses to the pain of social rejection is something for people dealing with addiction and the treatment of addiction to think about.
People with high rejection sensitivity (RS) “anxiously expect, readily perceive and react intensely to rejection”. (Leach and Kranzler, 2013.) They frequently “react in ways that undermine their relationships, ultimately serving as “self-fulfilling prophecies” and they tend to have lower self-esteem than people with low RS. Since they also exhibit higher levels of drug use than low-RS individuals it is important for addiction researchers and treatment professionals to know more about the different conditions that can promote and exacerbate RS.
Investigators from the University of Michigan Medical School and the University of Illinois collaborated on this experiment, which used brain-imaging technology and a simulated online dating scenario to see how activity in the mu-opioid receptor system in the brain was affected when depressed and non-depressed participants were exposed to social rejection.
The endogenous opioid system of the brain is intricately involved in controlling the human response to stress, regulating pain, and responding to analgesic opiate drugs. Research has shown that when the mu-opioid receptor system is activated, people report sensory and affective relief of pain. On the other hand, mice who lack the mu-receptor gene show increased sensitivity to painful stimuli and altered emotional responses.
There were 27 depressed participants in the present study and 18 similar but non-depressed participants. Each participant viewed photos and profiles of hundreds of other adults and identified the profiles of people they were most drawn to romantically. In other words, the experimental setting was similar to an online dating scenario. After making the selections, all participants underwent brain scans using positron emission tomography. During the scans, participants were told that the individuals they selected in the first part of the study were not interested in them. The scans made during the moments of rejection showed both the amount and location of opioid release as measured by the availability of mu-opioid receptors on brain cells.
The depressed individuals in the experiment exhibited reduced opioid release in brain regions regulating stress, mood and motivation. When participants were told that people liked them back, however, both depressed and non-depressed individuals reported feeling happy and accepted. However, the positive feeling in depressed individuals disappeared rapidly after the period of social acceptance had ended, and only the non-depressed people reported feeling motivated to connect socially with other people. According to a summary of this research in Science Daily, this feeling of wanting to be with others was “accompanied by the release of opioids in a brain area called the nucleus accumbens — a structure involved in reward and positive emotions”. The dramatic responses of the depressed participants to rejection occurred even though the researchers informed all participants ahead of time that the “dating” profiles were not real, and neither was the “rejection” or “acceptance.”
(Note release of natural opioids in non-depressed participants during period of social rejection (light spots) vs. limited response in brains of depressed participants.)
It is interesting to think about these results in connection with an earlier review of research about interpersonal stress and rejection sensitivity published in 2013 by by Leach and Kranzler. These investigators concluded that “substance-dependent individuals with high trait rejection sensitivity and a critical interpersonal environment are particularly vulnerable to relapse to substance use”. They attributed this vulnerability to the fact that social pain, like physical pain, causes suffering and speculated that there are individual differences in the ability to tolerate this suffering, a supposition that the current study, while small, appears to bear out.