September 23, 2013
The Brain Effects Of Cocaine Addiction Never Fully Go Away
Brett Smith for redOrbit.com - Your Universe Online
The modern approach to handling an addiction is to recognize it as a disease that cannot be cured – only managed. A new study in the journal Biological Psychiatry reinforces this notion: that a recovering addict is constantly haunted by their days of substance abuse – even after a long period of abstinence.
As researchers scramble to answer the 'chicken or the egg' questions surrounding addiction, they are becoming increasingly focused on finding out whether the brain is already hard-wired for addiction from birth or if certain substances push the brain to favor a pattern of abuse.
Previous research has shown that those who abuse psycho-stimulants such as cocaine are more impulsive and exhibit changes in the brain’s reward circuits as a result of using the drug. In the new study, scientists looked to see if brain alterations normalized after a prolonged period of drug abstinence.
The researchers began by comparing neural responses among three groups who performed a task that resembles bidding on eBay items. The three groups were made up of 47 healthy individuals who had no history of cocaine use, 42 addicts currently using cocaine and 35 former cocaine users who reported being drug free for an average of 4 years. The three groups were also tested on their levels of impulsivity and reward response.
The team found that active users exhibited unusual activation in several brain regions linked to reward processing. The former cocaine users exhibited differences in a subset of brain regions activated in the current users. However, both current and former users showed similarly boosted impulsivity measures compared to healthy control subjects, suggesting that these individuals were predisposed for addiction. The researchers added that the degree of impulsivity had a direct relationship with several of the brain activation anomalies.
The study authors said their findings indicate that protracted abstinence from cocaine may only normalize a certain subset of the brain function associated with active drug use.
"The knowledge that some neural changes associated with addiction persist despite long periods of abstinence is important because it supports clinical wisdom that recovery from addiction is a lifelong process," says Dr. John Krystal, editor of Biological Psychiatry and a professor of psychiatry and neurobiology at Yale School of Medicine.
"Further, it is the start of a deeper question: How do these persisting changes develop and how can they be reversed?"
The study authors said that future research should look into determining the degree to which differences in former cocaine users imitate aspects of pre-existing patterns, exposure to cocaine, or recovery.
As Connecticut scientists investigate the brain mechanics of addiction, a CBS affiliate in New York reported last week on a vaccine that is scheduled to begin human testing that would effectively treat cocaine addiction by blocking its effects.
Using a modified cold virus called an Adeno virus, doctors at Weill-Cornell Medical College in New York city were able to trick the body’s immune system into responding to the stimulant.
“The body thinks that it’s a cold virus, but really it’s the cocaine and the body makes antibodies against the cocaine,” said Dr. Ronald Crystal, who worked to develop the vaccine. “Think of it like little Pac-Man floating around in the blood and they’re Pac-Man against cocaine. Cocaine goes into the blood stream, antibodies bind to it, prevent it from getting to the brain.”
The vaccine essentially renders cocaine ineffective: removing the high and making the drug’s use a waste of money.