Some animals with behavior issues really respond to SSRIs, and while that's a whole other can of, uh, worms (worms with rudimentary pleasure centers!) – it turns out some animals really like to trip. West African elephants regularly eat the bark of the iboga tree, which has been used by people in the region as a sacred drug: "It's not a fun, pleasant, trippy high. It's inward turning." Siberian reindeer have also been observed to eat psychedelic mushrooms(http://www.metro.co.uk/weird/851202-reindeer-regularly-eat-magic-mushrooms-in-the-wild-research-finds) (leading to some almost certainly incorrect, but interesting speculation that these reindeer are the origin of the Santa Claus myth (http://www.geog.ucsb.edu/events/department-news/968/is-santa-the-personification-of-a-psychedelic-mushroom/)). In both cases, animals behave oddly when they eat the drugs, separating themselves from the herd, twitching, making strange noises – but they do use them again. "There seems to be some drive in us and in critters to alter our perception," Linden said.
Fascinating as that is, how is it relevant to social justice? First, Linden argues, observing animal behavior – and how basic the drive for pleasure can be – can give us a better understanding of the science of addiction. He noted that while just 25 percent of people who try heroin become addicted, 80 percent of people who try cigarettes become addicted – and the reason for that difference is that the drugs activate the pleasure centers in different ways. A single dose of heroin provides an enormous flood of dopamine, where cigarettes provide tiny, rationed neural rewards to the user. "It's like if you were training a dog, and wanted to reward him with a big steak, versus if you cut the steak up into bits and treat him throughout the day," Linden said. Most of us respond better to the tiny doses, and that's why cigarettes are actually harder to quit.
The research also tells us that addiction is highly varied in the way it manifests: that's why, with, say, alcohol, some people can take it or leave it, and some people struggle with it their whole lives. "We are, all of us, subject to various subconscious drives and motivations. The kinds of cravings one person experiences aren't like what another person experiences," Linden said. "If you understand the biology and medicine that makes sense is a disease model, and the only attitude that makes sense is one of compassion."