Ditching work next week to catch the opening of “Star Wars: Episode III – Revenge of the Sith”? If so, you may have more than a simple case of Han Solo mania. You may be exhibiting symptoms of a psychological disorder.

The mania among “Star Wars” fans is approaching its zenith, as the faithful don Chewbacca costumes and spend hours in Internet chat rooms guessing plot twists and coordinating group viewings. In Manhattan, members of NYLine, a New York City “Star Wars” fan club, started gathering April 30 outside the Ziegfeld Theater in anticipation of next Thursday’s premiere.

To the uninitiated, the sight of grown men standing on public sidewalks shrouded in Emperor Palpatine cloaks, clobbering one another with plastic light sabers, might seem evidence of extreme but innocent geekdom. According to a psychiatrist at New York-Presbyterian Hospital, however, taking “Star Wars” too far could indicate underlying, and potentially harmful, psychiatric conditions.

“What we’re dealing with here is a group of people with significantly low self-esteem,” said Alfredo Nudman, who is also an assistant professor of psychiatry at Cornell University’s school of medicine. Obsessed fans don’t really have a clear sense of self, he said, so they identify with fantasy characters onto whom they can project an ideal of “what they should be, what they are not, and what they feel they probably never will be.”

One thing some of the fans are not is at work. According to a study released Wednesday by the Chicago-based employment firm Challenger, Gray & Christmas Inc., the opening of what is said to be the final installment of the six-film “Star Wars” series will prompt a “significant spike in absenteeism on Thursday and Friday of the four-day opening weekend.” Accounting for lost wages and productivity, those who blow off work to wait in line for tickets, catch the movie, or recuperate the day after a midnight screening will set their collective employers back at least $627 million, the study said.

When enthusiasts eschew work, chores, family, and friends to stand on line outside a theater or spend hours online discussing the Skywalker family tree, they may also be retreating into a “childish fantasy world where they feel safer, and more fulfilled than they do in their own lives,” Dr. Nudman said.

That world is a simpler one, where the conflict between good and evil is painted in starker terms than in real life. In that classic struggle, most fans side with the good, Dr. Nudman said, “even though you see a ton of guys dressing as Darth Vader because they are choosing to identify for some reason with the darker elements within themselves.”

If your significant other has a penchant for dressing as Darth Maul, however, it need not be cause for concern. Inserting oneself into the world of “Star Wars” is evidence of a retreat into the adolescent to begin with, Dr. Nudman said, so a fan who identifies with the films’ villains is projecting “the badness of a little child, not the badness of a Ted Bundy.”

Where “Star Wars” obsession does become harmful, Dr. Nudman said, is when it begins to interfere with daily existence. When a fan burns money and vacation days attending “Star Wars” conventions in Las Vegas instead of bonding with the wife and children, or when an enthusiast gets in trouble with his boss for spending working hours and company computers buying Yoda masks off eBay, “then you’ve crossed into the pathological realm where you need treatment,” the psychiatrist said.

That treatment would involve psychotherapy for the underlying issues prompting the obsession, Dr. Nudman said, exploring such questions as “What is it about Darth Vader that you’re identifying with? What is it making up for in your life?”

Unfortunately, Dr. Nudman said, most of those who need that treatment don’t seek it, particularly because they are enabled by a merchandising empire that feeds off their obsession.

One “Star Wars” enabler, the editor of the New York-based online fantasy entertainment guide UGO.com, Eric Eckstein, however, said ditching work to catch Thursday’s premiere is obligatory for a “Star Wars” aficionado. Mr. Eckstein, who said the overwhelming majority of his company’s 50 employees were hard-core “Star Wars” lovers, said he was trying to help UGO.com balance those demands against the morale-killer of telling workers they can’t play hooky to catch the “Star Wars” premiere.

To avoid widespread absenteeism next week, Mr. Eckstein said, UGO.com used its connections to try to get employees to as many advance screenings as possible, rationing tickets so that no one would be “that guy at the water cooler who has to say he didn’t see it.”

Of fans who would have to ditch work to see “Episode III,” however, Mr. Eckstein was understanding. The opening-night experience, he explained, was irreplaceable.

When Mr. Eckstein and several colleagues attended the first showing of Episode II in 2002, the crowd’s adrenaline made the event, he said.

“It’s such a rush – everyone’s into it, so it doesn’t matter if the movie sucks,” he said.

That rush isn’t felt only by those in the fantasy industry. Another of UGO.com’s editors, Adam Swiderski, was a business consultant at Arthur Andersen when “Episode I” was released in 1999. He said he ditched work to see the movie three or four times in the opening weeks, and each time he was accompanied by someone at the firm.

Nor is the obsession limited to male loners. Some of the most diehard “Star Wars” enthusiasts at his company, Mr. Eckstein said, are married men. Fulfilling one’s longing for both Mos Eisley and human companionship is just a matter of finding the right partner. One UGO.com employee, Mr. Eckstein said, was lucky enough to find a bride just as “Star Wars” crazed as he, and the films’ “Throne Room” musical theme served as the processional at the couple’s wedding.

Dr. Nudman’s warnings aside, Mr. Eckstein questioned the stereotype of “Star Wars” nuts as introverted and troubled. Indeed, when people spend hours on a Princess Leia costume to parade around in at a “Star Wars” convention, it’s more altruism than pathology, he argued.

Such antics provide entertainment to receptive audiences, Mr. Eckstein said. The people who go to those lengths “feel like they’re giving back a little bit, they’re giving people joy.”

The fans, he said, know the appropriate boundaries for their behavior.

“They’re not going to work dressed up like Bobba Fett,” he said.