Magazine article Clinical Psychiatry News

Investigators Explore Nicotine for Tourette's, ADHD. (Spinning Straw into Gold?)

Magazine article Clinical Psychiatry News

Investigators Explore Nicotine for Tourette's, ADHD. (Spinning Straw into Gold?)

Article excerpt

Therapeutic is not a quality usually associated with nicotine. Addictive and deadly, perhaps, but therapeutic?

Over the past decade, nicotine and related drugs have shown the potential to treat a variety of psychiatric and neurologic disorders. The best evidence for efficacy comes from patients with Tourette's syndrome and those with attention-deficit hyperactivity disorder (ADHD). Benefit also has been seen in patients with Alzheimer's disease, Parkinson's disease, schizophrenia, and bipolar disorder.

Researchers caution that routine use of a nicotinic drug for any disorder is still years away. The clinical results so far have come from pilot, proof-of-principle studies. And it's very unlikely that nicotine itself would be a treatment agent. Study results with nicotine have shown efficacy, but they also have highlighted the drug's substantial adverse effects.

The development of nicotinic drugs has jumped in and out of favor with drug companies over the past decade--usually more for business reasons than scientific and medical issues--but now the field seems dearly back in the commercial limelight. Several major drug companies have nicotine-related agents that are in or entering clinical studies, but details on the scope of this proprietary work are kept under wraps by industry, experts said.

"The future is in related drugs," said Dr. Paul A. Newhouse, director of the clinical neuroscience research unit at the University of Vermont in Burlington. "Nicotine is not a dangerous drug, but it's a pretty difficult drug to use. It has a lot of bad effects that we'd rather not have." Treatment-limiting adverse effects include nausea, dizziness, and cardiovascular effects. Nicotine patches also can cause local skin irritation. But addiction is one downside to nicotine that is not much of a concern in a treatment setting.

"There is no evidence that nicotine or nicotinelike drugs are abusable. Outside of tobacco, the addiction potential is virtually nil," he said.

It's not fully understood why nicotine in cigarettes is addicting but nicotine in a patch or gum is not. Part of the reason may be the speed at which nicotine enters the body: Smoking creates a rush; patches don't. Another element is probably the social and sensory aspects that surround smoking that are missing when a patient self-applies a patch. And if a person was interested in abusing nicotine, they'd probably turn to tobacco.

The physiologic basis behind nicotinic drugs is simple. Nicotinic receptors exist throughout the brain and nervous system, which in part explains why nicotine is addicting. The nicotinic receptors are one of two acetylcholine-receptor subtypes; the other subclass is the muscarinic receptors.

Because of this, nicotine and related drugs have cholinergic actions, such as improving cognition, attention, motor function, mood, and executive function.

Probably the largest treatment experience with nicotine itself has been at the University of South Florida in Tampa, where nicotine has been used to treat about 100 children and adolescents with Tourette's syndrome, said Dr. Archie A. Silver, director of the university's division of child and adolescent psychiatry.

Starting in the early 1990s, he and his associates found that nicotine gum or a nicotine patch enhanced the action of neuroleptic drugs like haloperidol for controlling the motor and verbal tics of children with Tourette's syndrome. …

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