Why All Drug Highs Are Essentially The Same
Addictive drugs share what scientists call a “common neural currency,”1 the neurotransmitter dopamine. Drugs like alcohol, heroin, cocaine, marijuana and methamphetamine all create a high by overstimulating dopamine in the brain’s Reward System, the network responsible for pleasure, learning from it and the motivation to repeat the experience.
Addiction researchers say the dopamine high is essentially the same no matter what drug is taken. This may seem counter-intuitive, since some drugs, like alcohol and opiates, are depressants while others, such as cocaine and methamphetamine, are stimulants. Why do some make you sleepy, while others keep you awake? They’re side-effects from differences in the ways the drugs act in the brain and particularly how they affect non-dopamine neural networks. To an addict, however, it may be the very differences in the way drugs work that they find appealing. Some prefer sedative qualities while others are looking for an energy boost. But the high they experience is basically the same.
Dr. Roy Wise, of the National Institute of Drug Abuse, explains, “If you give an animal a general injection of an opiate like heroin, it is likely to slump to the floor and not get up. But if you inject heroin directly into the part of the brain where it is rewarding, it makes the animal run around like it was given amphetamine.” That’s because dopamine is “the common denominator of addiction.”2
Addictive drugs also have in common the way drug tolerance develops in the Reward System. In fact, tolerance is a key to why those drugs are addictive. Thus, scientists say, all addictions share the same “common denominator,” and all drug addictions have more in common than ways they differ.
However, there’s a least one factor that divides addiction into two different categories. For more on this, click on Differences In Addictions.
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1. Psychoactive Drug Use in Evolutionary Perspective, Science Magazine, October 3, 1997.
2. Alcohol Abuse Is Hereditary, medicalnewstoday.com, July 5, 2007.