Nicotine: It may have a good side

Nicotine: It may have a good side

It gets people hooked on cigarettes, but researchers hope that nicotine and related compounds will have therapeutic uses.

Nicotine is rightly reviled because of its associations with smoking and addiction. But the rogue substance has a wide range of effects on the brain, which may include some healing properties. Researchers are testing nicotine and related compounds as treatments for Alzheimer’s disease, Parkinson’s disease, attention deficit/hyperactivity disorder (ADHD), and other conditions.

Self-medicating with cigarettes

Epidemiological studies have hinted at nicotine’s therapeutic potential. During the 1980s, several found that smokers had lower rates of Parkinson’s disease than nonsmokers. Epidemiologists also validated what many mental health practitioners have long noticed: The smoking rate among people with schizophrenia, depression, and anxiety disorders is far higher than average. It’s widely believed that people with certain mental health problems are self-medicating with cigarettes because the nicotine helps their minds function better.

A most rewarding experience

Although the number of smokers is decreasing, smoking still accounts for roughly 1 in 7 deaths in the United States (1 in 3 between the ages of 35 and 70). And tobacco — particularly when smoked — is highly addictive. The cigarette sends the nicotine straight to the lungs, where it’s absorbed by the blood, carried to the heart, and pumped up to the brain. One aspect of addiction is withdrawal, and the symptoms of nicotine withdrawal usually begin within hours and consist of craving, irritability, anxiety, restlessness, and increased appetite. The craving may last for months — even years.

The psychological effects of nicotine at first seem contradictory: increasing alertness while providing a sense of relaxation and calm. One possible explanation is that the effect varies with the user’s initial state. For someone who’s agitated, nicotine has a calming effect. For someone who isn’t, it heightens alertness. This difference may also help explain why nicotine, unlike many other addictive drugs, doesn’t behave in a simple additive manner as the dose increases.

Nicotine is addictive because it triggers a reaction in the brain’s reward system, the structures responsible for giving us pleasurable sensations. More specifically, the drug intensifies the activity of the neurotransmitter dopamine in a part of the brain called the nucleus accumbens. Cocaine and amphetamines do much the same thing; nicotine is tame in comparison. But experts theorize that it may have an added effect because the drug amplifies the brain’s response to the behaviors associated with smoking. In other words, it’s not just nicotine, but the pleasurable sensations it confers on behaviors associated with smoking that make nicotine so addictive.

Nicotine can be addictive without cigarette smoke. For example, people become addicted to the nicotine in chewing tobacco and “dip” that is tucked next to the gums. As a rule, though, most drugs of abuse are not as addictive if they are delivered more gradually. In South America, coca leaves are chewed or used to make tea as a mild stimulant. Whatever the harmful effects, they’re a far cry from snorting cocaine. Methylphenidate (Ritalin) is chemically more or less the same drug as the injectable amphetamines made in illicit laboratories. But in pill form for treatment of ADHD the effects on the brain are so much milder that it changes the character of the drug, despite the chemical similarities.

Find More on MSN Health & Fitness:

• Nicotine Withdrawal Occurs in Just 30 Minutes
• Study Reveals Smoking’s Link to Breast Cancer

• Stop Smoking Guide

• Talk About It: Adults With ADHD