Exposure to the “stress hormone” cortisol may help reduce cravings among heroin addicts, recent research suggests. Dependence on opioids, usually heroin, affects an estimated 13 to 22 million people worldwide.
The researchers, from the University of Basel, Switzerland, say that heroin has an extremely high dependency potential that stimulates severe cravings in addicts. Stress has been shown to increase cravings and drug-taking behavior, hence the stress hormone cortisol might have a role to play in cravings. So the team studied the effect of cortisol on addictive cravings in heroin addicts.
Cortisol is a steroid hormone, made in the adrenal cortex within the adrenal gland, and released in response to stress and low blood glucose levels. The team has previously found that cortisol reduces a person’s ability to retrieve memories. In previous studies, when volunteers were exposed to the hormone they did less well on memory tests.
Dr. Marc Walter and the team in Basel report that this may be useful in order to relieve anxiety symptoms in patients, by inhibiting the patients’ ability to recall anxious memories. They investigated whether cortisol may also inhibit addiction-related memory, and hence drug cravings.
To do so, they recruited 29 patients undergoing heroin-assisted treatment. Participants took either a single oral dose of 20 mg cortisol or placebo, then a dose of heroin 105 minutes later. They were shown pictures of drug paraphernalia at various time points in the study and asked to rate their cravings.
Those who took cortisol showed an average 25 percent decrease in cravings, compared to those on placebo. But this effect was only seen for those who were dependent on a relatively low dose of heroin (113 mg to 305 mg per day), not among highly dependent patients.
The study is published in the journal Translational Psychiatry. Walter said it remains to be seen if cortisol can help patients reduce their heroin dosage or remain abstinent from heroin for longer. He adds that the study might have important clinical implications for the treatment of addictions, but calls for further studies to look at the mechanism behind the findings.
“Whether the inhibitory effect of cortisol on the craving for heroin will also affect addiction-related behaviors of patients in their day-to-day lives is still unclear,” he said. “The inhibitory effect of cortisol on addictive cravings might also have positive implications for nicotine, alcohol or gambling addiction.” .
The authors point out that heroin dependence carries the risk of fatal overdose, infection (including HIV and hepatitis C), social disintegration, violence and crime. Heroin dependence is usually a chronically relapsing disorder. Craving for heroin is described as “a subjective experience of wanting to use and re-experiencing the positive effect of the drug.”
Although opioid maintenance programs using regular opioid administration often have good outcomes, reducing illicit opioid use in heroin-dependent patients, a substantial number of patients continue to experience and act on heroin cravings.
“The present finding of a cortisol-induced reduction in craving suggests that cortisol is not mediating the enhancing effect of stress on heroin craving, but rather acting as a stress buffer,” the experts believe. “A possible mechanism for the craving-reducing effect of cortisol may be its effects on memory retrieval.”
Further evidence in support of this idea is that emotionally arousing information has been shown to be particularly sensitive to cortisol.
“Furthermore, there is evidence that cortisol can also reduce the retrieval of aversive memory and enhance fear extinction in posttraumatic stress disorder and phobia,” they added. But they did not see any effect of cortisol on the appraisal of drug-related pictures in this study, perhaps because the “stimuli were too strong to be influenced by cortisol.”
They also reported that, “The medium- and high-dose heroin consumption groups had more frequently an unemployment status as compared with the low-dose consumption group, indicating a more severe substance use disorder, which is generally less responsive to regular treatment interventions.” On the other hand, higher doses of heroin “may have interfered directly or indirectly with cortisol effects,” perhaps via the opioid system.
“It is possible that higher doses of cortisol might have been needed to reduce craving in patients receiving higher heroin doses,” they suggested. In future work, “it will be of considerable clinical interest to investigate the effects of repeated administration of cortisol and whether cortisol might be suited to prevent relapse in abstinent patients.”
Walter, M. et al. Effects of cortisol administration on craving in heroin addicts. Translational Psychiatry, 28 July 2015, doi: 10.1038/TP.2015.101