The idea that addiction is a disease of the brain is a myth, said the American neuroscientist Carl Hart, 54, in a lecture at Fronteiras do Pensamento, this Wednesday (24) in São Paulo. In the speech that also addressed individual freedom, racism and the war on drugs, he devoted part of his time to talking about the problems of science related to substance abuse.
The idea that drugs cause permanent damage to the brain or change the way brain circuits organize themselves became popular in the 1990s, especially after the then director of NIDA (National Institute for Drug Abuse), Alan Leshner, published in 1997 an editorial in the journal Science defending the theory. The DSM-5, mental illness diagnostic manual, also talks about structural changes in the addicts’ brains.
For Hart, scientific evidence does not allow such things to be affirmed. “How can you observe changes in the brain? We would have to take pictures of people’s brains before they take any drug and then compare, but that doesn’t exist,” he says.
In addition, the neuroscientist emphasizes that studies show that scientists cannot say who is a drug user and who is not just looking at imaging exams of their brains — that is, there are no definitive markers in the brain structures that indicate the use or abuse of drugs such as exist for other degenerative diseases such as Parkinson’s and Alzheimer’s.
Another problem with research on drug use is that the scientific literature on the topic tends to overemphasize the negative aspects, says Hart. For him, this is explained by scientists’ excessive caution or by their willingness to make their studies seem more meaningful. “There is an incentive to look for negative effects. It influences what we look for and therefore what we find” in the survey, he says.
Much of Hart’s research involves experiments in which he offers drugs or alternatives to people in the laboratory, whether they are chemically dependent or not. He says that, over the years, the main effect he observed in patients after using a drug was that they were happy. “Many said they loved me,” he recalls, laughing. “We have a huge database of experiments showing the positive effects of substances,” he says. “In those times, we seem to have forgotten about happiness. Drugs are something that improves people’s lives, but we don’t usually say that in public.”
At the end of the lecture, he recalls the guarantees of the Brazilian Constitution, such as freedom and equality, and argues that, with the prohibition of certain drugs, the promise is not being fulfilled. “We can fix this by regulating the sale and use of substances as we do with alcohol and tobacco. This would generate millions of jobs and large tax revenues.”
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