”This is your brain. This is your brain on drugs.” A man`s hand is shown, holding an egg sizzling in a frying pan. ”Any questions?” The television ad has played so often that the phrase has become a cliche, parodied on T-shirts around the world.
Scientists now are getting a more realistic view of the effects of drugs, especially cocaine, on the brain. Recent research has shown how cocaine use produces strokes and neurological defects and causes the user to crave the drug. But there is also increasing evidence that some of the damage caused by cocaine is reversible upon withdrawal from the drug.
Chronic cocaine use can damage the brain`s blood supply by inducing severe constriction of blood vessels, called spasms, which can starve parts of the brain of nutrients. Cocaine also increases heart rate and blood pressure, so repeated use can weaken and rupture blood vessels. Cocaine use has produced strokes and aneurysms, even in young users.
Dr. Leonard Holman and his coworkers at Boston`s Brigham and Women`s Hospital use SPECT (single photon emission computed tomography) imaging to look at damage to cerebral blood flow in 10 long term cocaine adults in a drug treatment program. They have been able to measure, for the first time, recovery after withdrawal.
A SPECT scanner detects a low-level radioactive tracer drug, injected into a patient`s bloodstream. The scanner produces images of blood flow in planes, or slices, in the body. Areas with abnormally low blood flow appear as dark patches in an otherwise bright image.
”The initial SPECT images of the addicts` brains appeared riddled with small holes,” Holman says. In those areas, the blood flow was only half the normal volume. The addicts also showed impaired brain function, as measured by psychological and motor skills tests.
After one week of abstention, the addicts` brains were looked at again. Blood flow in the ”holes” had increased by an average of 11 percent. After withdrawal periods ranging from 17 to 30 days, the blood flow increased an average of 23 percent, to nearly three-quarters of normal.
The result is significant, Holman says, because other researchers had suggested earlier that this sort of damage was irreversible.
In other work, researchers led by Eric Nestler at Yale University looked at the biochemical effects of cocaine in the nerve cells of rats. They found that cocaine changes the cells` chemical makeup.
Chronic drug exposure caused changes in the levels of proteins that control the cells` size and shape, and their ability to synthesize chemical messages. These changes could explain the powerful addicting properties of cocaine.
Dr. Robet Niven sees the effects of cocaine abuse every day, as head of the chemical dependency program at Detroit`s Harper Hospital. ”It has been clear for some time that some acute effects of cocaine are reversible,” he says. But there is increasing clinical evidence that chronic effects of cocaine use also are reversible upon withdrawal from the drug.
Acute effects of withdrawal, such as extreme depression, extreme lethargy and greatly increased appetite, disppear in two to three days, he says, while chronic psychological effects of cocaine use, such as paranoia and depression, can improve after six to 12 months off the drug. But, he cautions, ”we are still in the very early stages of understanding the chemistry of the brain.” Children born to cocaine-addicted mothers stand a chance of leading normal lives, Niven says. ”If they are raised in a healthy environment, when these children are 3 to 4 years old, there is no difference between them and other children.”
Niven believes one should not underestimate the effects of drug abuse, but he also cautions against overstating warnings. ”I`m a great believer in prevention,” he says. ”But fear, including fear of health deterioration, even death, has at best a very short-term effect on people`s behavior. The human mind has a great capacity to lie to itself, to say, `It won`t happen to me.”`
Many researchers now believe the worst effects of drug abuse may be societal and economic. Niven believes the new research provides additional motivation to seek treatment, since it gives hope that recovering addicts can avoid permanent mental and physical disability.
A video based partly on Holman`s SPECT brain images has been sent to middle schools across the country. It shows the damage caused by the drug, as well as the recovery of blood flow after withdrawal. To obtain the video, write J.J. Daley, 6 Tide St., Boston, Mass. 02210.
