These Doctors Gave Rats Morphine - And Changed The Way We Talk About Drugs

Decades have passed since the war on drugs began, yet many Americans across the country continue to see their communities ravaged by heroin and other opiates. Some critics of the war on drugs point to one controversial, animal-based experiment known as the Rat Park study, saying this experiment is partly to blame for the exacerbated effect of the so-called war.

The basis of the Rat Park study: a Canadian professor and researcher, Bruce Alexander, took two groups of rats and placed one in solitary confinement with access to two water bottles - one laced with drugs. Another group resided together in "Rat Park," basically a rat paradise where they had access to the two water bottles, as well as to partners, toys, and food.

Alexander learned the group in the park generally chose the non-laced bottle, while the solitary rats became morphine addicts. Alexander concluded the common understanding of drugs at the time - that the chemical makeup of drugs causes anyone to get addicted - was wrong, and that environment proved as significant.

Some in the medical and psychological communities say Alexander's study perpetuated false ideas about addiction. But many experts now surmise it's more accurate to say that while Alexander was wrong to pin addiction on a sole cause - in his case, environment - he still provided a valuable piece to the puzzle of addiction. A living being's surroundings do affect their propensity to become addicted to drugs, but the chemical makeup of drugs and other factors are also vital to understanding how one becomes an addict. 

Regardless, the Rat Park study and subsequent conversations about it provide a useful lens with which to view America's war on drugs


  • The Study Suggested Environment Plays A Role In Addiction
    Video: YouTube

    The Study Suggested Environment Plays A Role In Addiction

    Many people who grew up in the '70s and '80s remember the war on drugs' marketing ploy: if you use drugs, you will get addicted, and they will kill you. The "cocaine rat" commercial infamously portrayed a rat who became fatally addicted to cocaine.

    The original experiment dramatized by the ad prompted Bruce Alexander, head of the Rat Park experiment, to ask what the rat would do if it had other options. As the test stood, the rat had nothing to do with its time other than drugs.

    This question led to the creation of the "park," where rats had toys, other rats, substantial food, and access to both water bottles. The rats tried the morphine-laced water, but they generally chose otherwise. None of them died by drinking drug-laced water. Compared to rats in isolation, the rats in the park didn't drink a quarter of the amount of laced water.

    Alexander's second experiment took the addicted rats - the isolated ones - and put them in Rat Park after 57 days - meaning they could become heavy morphine users for 57 days before heading to the idyllic park. The rats generally stopped using drugs.

  • Soldiers' Drug Use Seemingly Supported The Study's Conclusions

    The Rat Park study suggested people can use addictive drugs and not get addicted. For example, historians now believe the Nazis fueled their military with methamphetamines, and after WWII ended, they assimilated back into society. Likewise, American soldiers addicted to heroin in Vietnam - around 15-20% of US forces - mostly did not continue using heroin when they returned home. Research at the time showed only 5% relapsed into drug use. 

    What was going on? Rat Park had a possible answer. Vietnam and WWII were horrible environments; remove people from the terrible situation, and they'll likely stop doing drugs. 

  • The Study Had Flaws
    Photo: pennstatenews / flickr / CC-BY-NC-ND 2.0

    The Study Had Flaws

    The Rat Park study relied on making a big assumption: the rats who lived in the park enjoyed idyllic lives. For humans, even ones with good and fulfilling lives, there is no "park" equivalent. The real world is much more strenuous. This gap in analogous environments makes it harder to draw parallel conclusions in humans from the Rat Park study. 

    Furthermore, while two studies completed after Rat Park replicated the general results, two more major studies did not. The Rat Park study also experienced malfunctioning equipment and a subsequent data loss. These issues might have affected Bruce Alexander's outcomes.

  • Anecdotal Evidence Challenges The Study's Findings
    Photo: Inge Habex / Wikimedia Commons / CC-BY-SA-3.0

    Anecdotal Evidence Challenges The Study's Findings

    The basic conclusion about Bruce Alexander and his Rat Park experiment suggested that environment has the most substantial influence over addiction. Rats with presumably happier lives didn't typically want addictive drugs; thus, Alexander concluded people with happier lives and environments also wouldn't want drugs. 

    However, carrying Alexander's conclusion one step further means people with happy lives and surroundings cannot become drug addicts. In reality, this isn't the case, as demonstrated by pervasive prescription drug abuse and the opioid epidemic. A scientific quantification of "happiness" is also relative, as one expert noted:

    There are thresholds below which material deprivation and poverty impact happiness, but above these thresholds quality of life and happiness are subjective and appraisal-based.

  • Addiction Understanding Has Changed Over Time

    By using Rat Park to devalue the idea of brain chemicals being the sole cause of addiction, experts changed how they understood addiction. But their new understanding still left holes in accounting for how the brain's chemical balance varies.

    How does taking something physical, like a drug, also play into sometimes intangible circumstances, like environment? Take the example of gamblers: some people are gambling addicts, but they're not necessarily ingesting anything. Thus, the change in brain activity is likely contingent on something else. 

    If environment and human connection are at least some of the forces behind drug addiction, then the war on drugs does nothing to alleviate those forces. In fact, it exacerbates them. According to one journalist, criminalizing drug use reinforces the brain activity and spawns further addiction:

    When we criminalize drugs and drug users, we ensure that the context of drug use habitually turns the brain toward shame, illegality, secrecy, and depravity. Do you know what else drives relapse to drugs of abuse? Stress and social isolation.

    We reinforce jails. We reinforce drug dealers. We reinforce violence. We reinforce the associated contexts of every other criminal enterprise that accommodates drug use. We habitually recreate a tragedy where the so-called solution causes the problem.

  • Factors Beyond Environment Can Make Someone Susceptible To Drug Use

    Most researchers admit how environment can and does affect addiction. However, further studies show many other factors at play. Genetics are predominantly responsible; studies have discerned genes specifically linked to various diseases and addictions, including nicotine addiction and alcoholism.

    What's more, early trauma can change the hypothalamic-pituitary-adrenal axis. This means someone with childhood trauma is more likely to abuse drugs or suffer from the effects of anxiety or stress.

    The bottom line: humans can control their environment only to an extent - a child has no control over the life, environment, and genetics into which they're born. While environment, friendship, and human connections all matter, addiction has more nuances than Rat Park demonstrates.