It's long been known that monkeys can get addicted to various opiates just like humans can. A new research showed that social standing matters in the "monkey addiction problem" (if there's such a thing).
It turns out that having a lower social standing increases the likelihood that a monkey to choose cocaine over food when stressed:
... [Robert Warren Gould and colleagues] looked at the effect of the stressful situation on the likelihood that monkeys would use cocaine. After the 40 minutes in the unfamiliar cage surrounded by other monkeys, each monkey could choose between pressing a lever that they knew delivered cocaine or one that they knew delivered a food reward. The subordinate monkey was more likely to choose cocaine while the dominant monkey was less likely to choose cocaine after this encounter, compared to their respective typical choices during the days preceding this encounter.
These differences in both brain activity and the likelihood of using cocaine between animals of different social rank offer clues to the social context of drug use and addiction in humans, say the researchers. Nader said, "We believe this type of research can be used to identify better treatment strategies, including providing environmental enrichment, that may affect the likelihood of abusing drugs."