Interview with Dr. Bankole Johnson of the University of Virginia

Tailoring addiction medicine to fit the disease.

(The “Five-Question Interview” series.)

25 years ago, when Dr. Bankole Johnson first began giving lectures about addiction and neurotransmitters in the brain, he had a hard time getting a hearing. That’s because 25 years ago, everybody knew what addiction was: a lack of “moral willpower.” Or, at best, some sort of psychological “impulse control” disorder.  

As a neuropharmacologist by training, and currently professor and chairman of the University of Virginia’s Department of Psychiatry and Neurobehavioral Sciences, Dr. Johnson thought otherwise, and went on make a name for himself by discovering that topiramate, a seizure drug that boosts levels of the neurotransmitter GABA, could be used in the treatment of alcoholism. “I just wasn’t a hospital-type doctor,” he once said. “I was for more intersted in research than clinical practice.” Johnson’s work was featured in the 2007 HBO series, "Addiction."

Born in Nigeria, Dr. Johnson attended the University of Oxford and received his medical degree in Glasgow, Scotland in 1982. At the time, medical understanding of addiction was poor to nonexistent. “Everything we knew—really knew—probably could be written on the back of a postage stamp,” he recalled.

Since then, Dr. Johnson has published numerous articles on psychopharmacology and addiction, and has served on several National Institutes of Health committees and panels. (See my earlier POST on Johnson’s study of drugs for addiction in the American Journal of Psychiatry.)


1. You’re a native of Nigeria. How did you first become interested in medicine?

Bankole Johnson: My father was a doctor and encouraged me. Back then, I had little interest in medicine and was more interested in the arts and perhaps going to law School, for which I had been promised a scholarship.

2. Addiction is called a “disease of the brain,” in Alan Leshner’s famous phrase, but it is still a hugely controversial subject. Are innate biological differences the cause of addiction?

Johnson: Addiction is a brain disease. The roots of the disease lie in brain abnormalities, and these are exacerbated when a vulnerable person uses alcohol excessively or takes illicit drugs.

3. How did you discover that topiramate helped some alcoholics drink less?

Johnson: It was an idea that developed from a hypothesis I came up with based on brain neurochemistry. The central idea was to alter the signals of dopamine, a critical path for the expression of rewarding behavior, through two different and opposite systems—glutamate and GABA.

4. That work led to Topamax for alcoholism, and your more recent work with ondansetron, another GABA antagonist. But what role do environmental and sociocultural factors play in the development of addiction?

Johnson: The environment interacts with genes and brain chemistry to govern behavior. But in the end, it is the changes in the brain that ultimately direct alcohol and drug taking behavior.  The environment therefore provides the context and tuning of the neurochemical signals in the brain.

5. Some people find the notion of addiction as a progressive and incurable condition a hard pill to swallow, so to speak. Why has effective medical treatment for addiction been so slow to develop, and why hasn’t talk therapy been more effective?

Johnson: Talk therapy has some effectiveness, but alone it is not a comprehensive or robust treatment. Progress in the last two decades has been quite rapid. With growing and clear acceptance of the neurobiological underpinnings of addiction, the next decade should herald even more exciting discoveries.  For example, our work on pharmacogenetics promises to provide effective medications—such as ondansetron—that we can deliver to an individual likely to be a high responder, based on his or her genetic make up.

Photo Credit: Luca DiCecco

The Cocaine Conundrum

Effective treatment remains elusive.

For addiction to cocaine, amphetamine, and other stimulants, the treatment picture has been complicated by the lack of any truly significant anti-craving medications. (See post, “No Pill for Stimulant Addiction"). The National Institute on Drug Abuse (NIDA) has yet to approve any medications for the treatment of either cocaine or amphetamine addiction.

Take the case of cocaine. Partly the problem stems from the direct effect cocaine has on dopamine transmission.  The hunt for a pharmaceutical approach to blunt that effect is complicated by the problematic nature of dopamine receptors.  Dopamine antagonist drugs like the antipsychotic drug haloperidol do not always block the stimulant rush. And their side effects, such as lethargy, emotional blunting, and tardive dyskinesia, make them unsuitable for ongoing addiction therapy. Conversely, some drugs that act as dopamine agonists turn out to be addictive in their own right. Many designer drugs are like that.

Because of all this, different approaches may be needed. The direct ride to the pleasure pathway provided by stimulants makes it difficult to tamper selectively with their effects. An antibody that would reduce cocaine consumption and sop up cocaine molecules in the brain, a kind of vaccine against cocaine, is one approach being pursued (See post, “Cocaine Vaccine Hits Snag”).

But other avenues of attack are being exploited.  Scientists in NIDA’s Intramural Research Program are testing compounds that target certain proteins known as dopamine transporters. Transporters move dopamine molecules in and out of the synaptic gap between neurons in the brain. Interfering with that transportation system is another way of altering dopamine uptake, and it represents one active avenue of approach to the treatment of cocaine addiction.

The researchers tested Benztropine Mesylate (BZT), brand name Cogentin, one of a class of drugs known as anticholinergic suppressants commonly used in the management of Parkinson’s disease. What exactly does benztropine do? It possesses both anticholinergic (acetylcholine-blocking) and antihistaminic effects. It has chemical similarities to atropine, which is used for Parkinson’s and for heart disease.

To begin with, the researchers wanted to establish that benztropine itself is non-addictive. By substituting different BZT analogs for cocaine during self-administration testing on addicted rats, “two of the three BZT analogs that were tested significantly reduced drug self-administration… which indicates that those BZT analogs themselves have low potential for abuse.”

Next, the cocaine-addicted rats were given different BZT analogs before they got their cocaine. “When given before rats had access to cocaine in the self-administration chambers,” the researchers reported in the Journal of Pharmacology and Experimental Therapeutics, “two BZT analogs also significantly reduced the number of times the rats would press a lever to receive cocaine.” Monoamine uptake inhibitors were used as a control. The authors conclude that “these compounds are promising candidates for the development of medications for cocaine addiction.”

Hiranita, T., Soto, P., Newman, A., & Katz, J. (2009). Assessment of Reinforcing Effects of Benztropine Analogs and Their Effects on Cocaine Self-Administration in Rats: Comparisons with Monoamine Uptake Inhibitors Journal of Pharmacology and Experimental Therapeutics, 329 (2), 677-686 DOI: 10.1124/jpet.108.145813

Photo credit: http://www.drugabuse.gov