Is it possible that the reason you are or are not addicted to drugs is due to the strength of the social network that surrounds you and the support it provides you? Could meaningful social interaction replace or even reverse the appeal of or even the addiction to drugs? Is the way we treat addicts in society completely counterproductive? Often, they are isolated from family either from a lack of understanding or due to being put in prison for their illness. Researchers are hoping to find a natural means of preventing drug abuse and drug addiction and they just might be onto something.
Researchers subjected rats to have a conditioned place preference for either a compartment that had the opportunity for social interaction with other rats of the same age and sex, or a compartment that offered the chance to ingest cocaine. A conditioned place preference measures the amount of time a subject spends in a place associated with a given reward and is used to infer affinity for said reward. After being placed in a neutral container, the researchers measured CPP. Once the rats were sufficiently conditioned to either social interaction or cocaine, a number of different experiments were done. The levels of stress in a rat could be observed by their behavior during grooming, the levels of a hormone in their urine and by looking into the brain for proteins present that may be responsible for the behaviors related to stress, measuring proteins present that are suspected to be related to the stress, and proteins related to forming CPP. The researchers measured the levels of CRF in the rats. CRF (or corticotropin releasing factor) causes a gland in the brain known as the pituitary gland (the “master gland”) to release a hormone (adrenocorticotropic hormone) that stimulates the adrenal glands above the kidneys to release what is commonly known as the “stress hormone” – cortisol. The other neurological measure looked at the levels of stress-activated proteins (p38 MAPK) in an area of the brain (the shell of the nucleus accumbens) associated with excitatory effects of stimuli and the anticipation of reward (Corbit, 2001).
After being conditioned, the rats were injected with either control saline, CRF, or alpha helical CRF. Alpha helical CRF is an inhibitor of CRF, meaning that it blocks CRF from telling the pituitary gland to have the adrenal glands produce stress hormone. Rats with a CPP for cocaine who were injected with CRF showed an increased cocaine CPP, meaning that the higher the level of stress, the more affinity they showed for drug abuse. Conversely, injection of the CRF inhibitor decreased the conditioning for cocaine preference significantly, while also decreasing the grooming behaviors indicative of stress in rats. In the rats who had social interaction CPP, injection of CRF did not affect their social preference. However, injection of CRF inhibitor increased the social interaction CPP even further. Finally, when cocaine CPP rats were offered the option to partake in social interaction instead of the cocaine, the cocaine preference was reversed to the same level as the rats receiving the CRF inhibiting protein injection. This shows that social interaction has the same effect as the blocking of the stress hormone by injection.
Furthermore, the researchers injected the rats with a cocaine CPP with a different inhibitor. This one inhibited the p38 MAPK protein that, as mentioned before, is associated with the anticipation of reward associated with addiction. These rats, when injected before conditioning, showed a much lower CPP for cocaine. Levels of p38 MAPK were also measured from the brains of rats after social interaction and after the inhibition of CRF. In both of these conditions, the levels of p38 MAPK were lowered. This indicates that the release of CRF and the associated stress when taking drugs causes levels of p38 MAPK to be higher (as observed in the cocaine CPP rats) in the shell of the nucleus accumbens and that this relationship between stress/drugs and the proteins they release are associated with addiction.
The fact that social interaction was preferred after cocaine CPP and that the subsequent levels of p38 MAPK and CRF in the brain were lower in those who had social interaction indicates that there may be an answer for drug addiction in humans that lies in the social relationships we form and the support networks we have around us.
Avery, S., Clauss, J. & Blackford, J. (2016). The Human BNST: Functional Role in Anxiety and Addiction. Neuropsychopharmacol. 41: 126–141. Web: https://doi.org/10.1038/npp.2015.185
Corbit, L. H., Muir, J. L., and Balleine, B. W. (2001). The Role of the Nucleus Accumbens in Instrumental Conditioning: Evidence of a Functional Dissociation between Accumbens Core and Shell. The Journal of Neuroscience. 21(9):3251-3260.