of major depression.
"These weren't average smokers," Glassman points out. All were heavily dependent on nicotine, they smoked at least a pack and a half daily, had their first cigarette within a half hour of awakening, and had tried to quit, on average, five times before. It is possible, he suggests, that nicotine has an antidepressant effect on some.
More generally, suggests Brandon, the very effectiveness of cigarettes in improving affect is one thing that makes it so hard to quit. Not only does a dose of nicotine quell the symptoms of withdrawal (much more on this later), the neurotransmitters it releases in the brain are exactly those most likely to elevate mood.
For a person who often feels sad, anxious, or bored, smoking can easily become a dependable coping mechanism to be given up only with great difficulty. "Once people learn to use nicotine to regulate moods," says Brandon, "if you take it away without providing alternatives, they'll be much more vulnerable to negative affect states. To alleviate them, they'll be tempted to go back to what worked in the past."
In fact, negative affect is what precipitates relapse among would-be quitters 70 percent of the time, according to Saul Shiftman, Ph.D., professor of psychology at the University of Pittsburgh. "We invited people to call a relapse-prevention hot line, to find out what moments of crises were like; what was striking was how often they were in the grip of negative emotions just before relapses, strong temptations, and close calls." A more precise study using palm-top computers to track the state of mind of participants is getting similar results, Shiftman says.
Most relapses occur soon after quitting, some 50 percent within the first two weeks, and the vast majority by six months. But everyone knows of people who had a slip a year, two, or five after quitting, and were soon back to full-time puffing. And for each of them, there are countless others who have had to fight the occasional urge, desire, or outright craving months, even years after the habit has been, for all intents and purposes, left behind.
Acute withdrawal is over within four to six weeks for virtually all smokers. But the addiction is by no means all over. Like those who have been addicted to other drugs, ex-smokers apparently remain susceptible to "cues," suggests Brandon: Just as seeing a pile of sugar can arouse craving in the former cocaine user, being at a party or a club, particularly around smokers, can rekindle the lure of nicotine intensely.
The same process may include "internal cues," says Brandon. "If you smoked in the past when under stress or depressed, the act of being depressed can serve as a cue to trigger the urge to smoke."
Like users of other drugs, Henningfield points out, addicted smokers don't just consume the offending substance to feel good (or not bad), but to feel "right." "The cigarette smoker's daily function becomes dependent on continued nicotine dosing: Not just mood, but the ability to maintain attention and concentration deteriorates very quickly in nicotine withdrawal."
Henningfield's studies have shown that in an addicted smoker, attention, memory, and reasoning ability start to decline measurably just four hours after the last cigarette. This reflects a real physiological impairment: a change in the electrical activity of the brain. Nine days after quitting, when some withdrawal symptoms, at least, have begun to ease, there has been no recovery in brain function.
How long does the impairment persist? No long-term studies have been done, but cravings and difficulties in cognitive function have been documented for as long as nine years in some ex-smokers. "There are clinical reports of people who have said that they still aren't functioning right, and eventually make the 'rational decision' to go back to smoking," Henningfield says.
The conclusion is inescapable that smoking causes changes in the nervous system that endure long after the physical addiction is history, and in some smokers, may never normalize.
The wealth of knowledge about smoking clarifies 