Cocaine Accelerates Brain Aging
Cocaine addiction accelerates the normal aging of the brain, according to new research.
By scanning the brains of 60 individuals with a cocaine dependency, and comparing them with 60 non-drug-using volunteers, Dr. Karen Ersche and colleagues at the University of Cambridge found a dramatic difference in how quickly their brains age.
Dr. Ersche had noticed that her middle-aged cocaine-addicted patients have problems with memory and attention which are usually seen in old age, and decided to investigate. "What I found was that the healthy people lost about 1 ml per year [of brain volume], but the rate of aging was greater in the cocaine users; they lost twice as much grey matter as the control volunteers," she explained.
This loss of volume particularly affected the prefrontal cortex, at the front of the brain, which is involved in attention and control of behaviour, and the temporal lobes, which are important for memory and speech. Cells die in these areas as part of the normal aging process, but this was happening more rapidly in people addicted to cocaine.
But there was one part of the brain where cocaine slowed aging, rather than speeding it up: the striatum. This region is rich in the 'reward' hormone, dopamine; stimulant drugs, such as cocaine, give you a high by causing dopamine release, and the striatum is often enlarged in people who regularly take these drugs. In contrast, loss of dopamine is thought to contribute to many of the problems of aging - so the fact that chronic cocaine use seems to halt this loss could help us to better understand the role of the striatum and dopamine in aging.
The United Nations estimates that around 21 million people worldwide use cocaine, and about 1% will become addicted. It's not clear from this initial study whether only those who become addicted will have this accelerated aging; Dr. Ersche points out that "we need to look at the pathology underlying this. How much cocaine is necessary to induce these changes needs to be investigated."
Not only is this information important for the growing population of aging drug users, but we may also be able to learn about normal aging from work like this. As Dr. Ersche put it, "it would be nice if the drug users could help us healthy people to learn about ourselves."