Animal study highlights importance of social support in relapse prevention

For the first time, scientists have proven the importance of social interactions in substance-using behavior in an animal study. The study, published in the November issue of Nature Neuroscience and conducted by Marco Venniro, PhD, and colleagues at the National Institute on Drug Abuse (NIDA), has implications for people as well.

Venniro explained in an interview with Addiction Professional that social interaction can affect drug craving and relapse, key barriers to recovery from substance use disorders (SUDs).

“This relates to humans because an addicted environment is usually social by nature,” says Venniro, a postdoctoral fellow in the Behavioral Neuroscience Research Branch of NIDA's Intramural Research Program. A co-feature of addiction is loss of social support, he says. “If you are addicted, you risk losing your family, and your job.” This is why community reinforcement helps.

Not the same as 'rat park'

Called the Community Reinforcement Approach (CRA) in this study, the model is completely different from that used in the famous (or infamous) “rat park” study, says Venniro.^1,2,3 In the rat park study, lab animals that were housed in groups were protected from being addicted, and were given the choice between social life and drugs. For the new study, the researchers used animals that were already addicted, then giving them a choice between the drug and social life.

The addicted animals learned that if they pressed a lever inside their box, a door would open, and allow access to another animal. The animal was given a choice between the interaction with the social partner (who was drug-free) and the drug. The researchers showed that the rats—even though they were addicted—repeatedly chose social interaction over heroin or methamphetamine. This was even true for rats that had previously been using the drugs compulsively—an animal model that correlates with SUD in humans.

In addition, the rats chose social interaction over more drugs even if they were continuously housed with other animals. These co-housed animals were significantly less likely to go back to drugs than rats not housed with peers, after drugs were withdrawn.

Click here for the Venniro study abstract.

Humans are different, but…

The researchers wrote that “humans evaluate social interaction using a global frame of reference in which the most highly valued outcome is what sociologists call ‘a stake in conventional life’—that is, meaningful participation in society or its institutions, above and beyond the momentary presence or absence of a companion.” So the human “social reward” by definition is not as “immediate or concrete as a drug reward.” This creates a “choice bundling,” in which people who expect to maintain a take in conventional life want to avoid addiction, but people whose expectations are “bleak” instead can rationalize self-destructive behavior.

These considerations don’t exist for rats, whose choices generally are based on what happens in the next minute, or less. “Rats also do not have a cultural frame of reference for the reward value of social interaction,” the researchers wrote. “We think these two species differences—one in time horizons, one in a cultural frame of reference—largely account for the fact that simple access to a conspecific [member of the same species] is more protective against drug choice for rats than for humans.”

However, humans do respond well to behavioral treatments that give immediate and predictable social reward. “Unlike rats, addicted humans can also benefit from cognitive treatments that make distal nondrug rewards (including social rewards) more salient during watershed moments of choice; this is central to cognitive–behavioral therapy and to acceptance and commitment therapy,” the researchers wrote.

They added, “Our findings underscore the soundness of all these approaches and suggest that CRA, in particular, merits more attention as an addiction treatment.”

Not all human drug users are protected against the development of an addiction, even if they have a stake in conventional life. And not all humans with addiction respond to social supports. This is why, the researchers wrote, even patients with ample social rewards do not achieve remission 100% of the time. It will be useful to understand how social reward in animal studies could be used to identify these harder-to-treat cases.

Using established models of drug addiction, relapse and craving, the researchers found that access to social reward prevented compulsive self-administration of heroin and methamphetamine in rats that were already addicted. The social reward access also prevented incubation (the development of craving in lab animals after a prolonged period of drug self-administration).

“From a clinical perspective, our findings support wider implementation of social-based behavioral treatments, which include not only CRA but also innovative social-media approaches, like those being implemented for other psychiatric disorders to provide social support before and during drug-seeking episodes,” the researchers concluded.

Challenges of research

“It was hard to convince people that this model was going to work,” says Venniro. “It wasn’t easy, because the social factor is not well integrated into addiction science.” But once the researchers started presenting their results, various labs started using the social model, he says.

“We hope this model can convince more people to integrate social treatment,” Venniro says.

However, doing the research with humans involves a huge challenge: Designing something that resembles the “box” in the animal study just wouldn’t work. In addition, the social concept is different from how it applies to animals, because humans “know what they are expecting,” Venniro says. It’s very difficult to make sure all elements are controlled for. “But I am very positive” about the model and incorporating it into treatment, he says.

The “beauty of this new model is that we can now see if there are some brain mechanisms” that can help maintain abstinence, he says.

References

1. Alexander BK, Coambs RB, Hadaway PF. The effect of housing and gender on morphine self-administration in rats. Psychopharmacol 1978; 58:175–9.

2. Hadaway PF, Alexander BK, Coambs RB, et al. The effect of housing and gender on preference for morphine-sucrose solutions in rats. Psychopharmacol 1979; 66:87–91.

3. Alexander BK, Beyerstein BL, Hadaway PF, et al. Effect of early and later colony housing on oral ingestion of morphine in rats. Pharmacol Biochem Behav 1981; 15:571–6.