It didn't occur to Denny, a 33-year-old construction worker, that he might have a problem until he took $800 from proceeds of a golf tournament for which he was responsible.

"I was going to double the money and then put it back. Of course, I lost all of it and was unable to put it back. Naturally, I lost my job as a result. I told them I would work it off, pay it back. They didn't understand. I wasn't sick, I was just a thief and that was it. I didn't fully understand it myself at the time."

Bill, a 42-year-old executive, didn't recognize a disruption in his life until he found himself pawing through a trash can at the race track in search of a lost parimutuel ticket.

"In the middle of raking through all this garbage I just became aware of what I was doing. There was a frozen moment where I found myself asking myself, 'What level am I bringing myself to and where am I headed? Here I am, a successful businessman with a good reputation, and here I am going through a garbage can trying to find a ticket.' "

Denny and Bill (not their real names) are compulsive gamblers, two of an estimated 2 million nationwide, according to the Washington Center for Pathological Gambling, a private nonprofit treatment facility in College Park. What distinguishes them from 110 million social gamblers in this country is their addiction to the "action," their inability to stop despite repeated losses, and work, social and family turmoil.

Theirs is the "pure addiction," according to mental health practitioners treating compulsive gamblers. The American Psychiatric Association in 1980 labeled pathological gambling a disease, and some private insurance plans provide coverage for treatment.

"It is purely psychological in that you don't have to consume as with substance abuse," says Robert Politzer, research director of the Washington Center. "Here the substance is an activity that one engages in.

It's an impulse-control disorder where the thoughts and actions of gambling are almost instantaneous. In order to break that chain . . . something or somebody has to help out."

Although research and treatment of compulsive gambling dates back to 1972, the scientific community has only recently begun to look at it seriously. A current National Institutes of Health study is investigating physiological links to chronic impulsive behavior.

Meanwhile, compulsive -- or pathological -- gambling is still not generally accepted as an addiction comparable to alcohol and drug dependency.

"Part of the public's perception is of a kind of Damon Runyon character or a depiction in a Kenny Rogers' song," says Clark Hudak Jr., director of the Washington Center. "These are typical portrayals. The public really doesn't understand that it's actually a disorder."

Many compulsive gamblers find themselves constantly tempted and trapped in a society that sanctions gambling: 60 percent of all adults in this country indulge in some kind of gambling and 80 percent endorse legal gambling, according to the Maryland Public Gaming Research Institute.

"A horse-racing program was coming on TV and I immediately switched the channel," says Bill. "There was a tinge, a temptation there, but I knew I had to turn it off. I can't watch it."

Many compulsive gamblers (including Denny and Bill) share these personality traits: articulate, competitive, hard-driving, searching for something missing in their lives. Compulsive gamblers often have unusually high energy levels which, according to practitioners, make them vulnerable to the competition and aura of gambling.

Denny, fresh out of high school, felt a lack of direction, a void in his life. A friend introduced him to horse racing, and he walked out of a local track his first time with $60.

"Winning, naturally, made it easier for me to say 'Yes' the second time that he asked me to go. I just started a trend where I ended up going once a week, then a couple times a week, then three or four times a week because of the excitement, the action."

At this point, many compulsive gamblers are already hooked, according to Dr. Robert Custer, a Veterans Administration psychiatrist and a pioneer in the study of compulsive gambling.

"Now he knows it's easy to do. Another win is just the next bet away . . . Gambling gives him a level of euphoria, excitement and stimulation that relieves all pain, worry, tension, anxiety, depression, and it's so effective in doing that."

Denny began to exhibit the compulsive gambler characteristic that Politzer calls "magical thinking" -- a belief by the gambler that he is immune to the odds. Such thinking attracts the gambler to long-shot bets and usually causes an escalation of losses.

"We ask," says Politzer, " 'Why can't they develop some discipline like us who know the basics of probability?' and wonder why these individuals continue to bet on 13-to-1 shots.

"There is a magical thinking that they have some inherent power to beat the odds. It's almost a religious aura. And why do they do this? Because it happened early on."

Bill, married with two children, was a teen-ager when his father took him to the track. But it wasn't until he was in his thirties that he began gambling regularly to escape from a family crisis.

"I had a lot of difficulties with one of my children who had a drug problem. The disappointment of having my expectations and hopes for that child not realized was a big factor. Up until that time I felt I could handle pretty much any problem that came my way. I gambled to find relief."

Bill's initial exposure to gambling by a role model, and then his delayed addiction triggered by a personal crisis, are typical of many compulsive gamblers, according to professionals.

"The common denominator is that the compulsive gambler tends to use gambling as an outlet," says Hudak. "His addiction is to the action of the game, and he uses it as a coping mechanism."

Like Denny, Bill became a scientific handicapper and succumbed to the "big win" and "magical thinking" theories that he perceived would allow him to stop.

Instead, he went through the inevitable long losing phase that professionals say 90 percent of compulsive gamblers experience. Handicapping and, at times, even winning lose their importance.

"I bought books on how to handicap and studied all the techniques, all of which became totally lost once the compulsion took hold," says Bill. "That's the addictiveness of the action, the escape of self-delusion. I was still holding on to the idea that I was going to someday win big and solve all my problems in one big hit. It led to a growing awareness of being on a roller coaster that was very difficult to get off of, and yet I knew I had to get off."

Denny also found himself on a relentless roller coaster. He eventually blew most of an $11,000 inheritance.

Denny and Bill became submerged in the isolated world of the compulsive gambler, following almost every impulse to gamble, escaping self, family and work responsibilities. The compulsive gambler at this point begins to confront the addiction, therapists say, and the pain of trying to get off the roller coaster.

"The winning and losing is almost anticlimactic. When the race is over and the winner is declared, there is no ambiguity anymore," says Politzer. "The excitement comes in not knowing what the outcome is going to be. When the outcome comes it triggers the need for another ambiguous situation."

"The anticipation of gambling is euphoric, nirvana, a fantasy world," says psychiatrist Custer. "He feels great when he's gambling, but it's nothing compared to the misery he feels afterwards. It's that misery he feels when he's not gambling that drives him back to gambling."

The compulsive gambler usually seeks treatment on his own only when the pleasure of gambling deteriorates and no longer satisfies the pain and problems of his nongambling life, according to Custer.

"The gambling is a pleasure disorder, but as he has more and more social problems because of it the scale comes up and he derives less and less pleasure from gambling. He seeks treatment when he realizes he can never balance all the pain environmentally with gambling."

Bill joined the Silver Spring chapter of Gamblers Anonymous (GA), a national self-help program modeled after Alcoholics Anonymous.

GA, which now has about 700 chapters nationwide and more than 15,000 members, is considered one of the most effective forms of treatment for compulsive gambling.

"There are always two GA meetings," Custer says. "The first is the formal meeting. But if you wait till they close the meeting, that's when you see the affection, when they take someone with a problem aside and ask if they can help."

Despite periodically attending GA meetings and plugging himself into GA's hotline and support network, Bill experienced "slips." "There was a series of disappointments, a depression that kind of came over me and I found myself in a situation where I was very easily tempted and did not resist it."

Such relapses are natural, according to Politzer. What's important is how the compulsive gambler responds.

Bill accepted the consequences of his slip. What he had learned about himself and his disorder had had an influence on his reaction.

He sought further treatment from the Washington Center for Pathological Gambling in hopes of targeting what he felt were underlying causes of his addiction.

One technique employed by the Washington Center is the Awareness Wheel, a poster board casino-type wheel illustrating six steps -- from thought to action -- that the gambler has an option to take.

"The normal process that healthy individuals go through of making a decision starts with a thought, then some values are brought in, needs, some judgments made," says Politzer. "It may happen quickly, but we do take these steps in making important decisions in our lives."

With compulsive gamblers, he says, therapists attempt to widen the gap between thought and action "and then start to put things in that gap."

Curing the gambler, therapists acknowledge, can be difficult. Says Denny, who is in an in-patient program: "I'm still feeling the addiction."

The difference now is, "I am not looking for a quick change. I'm looking for something I can work at."