Exactly when Charlie Sheen’s craziness stopped being funny is difficult to pinpoint. Many people were still laughing last Monday when, in an interview aired on the Today show, the actor proclaimed: “I’m tired of pretending like I’m not special… a total fricking rock star from Mars.”

The laughter faded as Sheen continued his weeklong media blitzkrieg, prompted by the decision of CBS to cancel taping of his situation comedy Two and a Half Men in the middle of its eighth hit season. Sheen was interviewed on ABC, NBC, and CNN, as well as by the online gossip site TMZ. Some people were still laughing Tuesday when the British Guardian newspaper offered an online quiz with a series of 10 outlandish quotes, asking readers to guess whether they were from Sheen or Libyan dictator Moammar Gaddafi.

Yet as the $2-million-an-episode star of television’s No. 1 primetime show kept spewing deranged gibberish in public — “These resentments, they are the rocket fuel that lives in the tip of my saber” — it became obvious that Sheen was not being intentionally funny. People weren’t laughing with Charlie, they were laughing at Charlie, and some weren’t laughing at all.

Celebrity psychiatrist Dr. Drew Pinsky described Sheen’s condition as a “psychiatric emergency,” most probably the manic phase of bipolar disorder (also known as manic depression) and requiring hospitalization: “He’s in an acute manic state right now.… Notice how he goes from thought to thought and they are sort of disconnected? That’s acute mania.” Practicing clinicians seldom offer such remote diagnoses of public figures, which can be deemed an ethical violation of the so-called “Goldwater Rule.” However, Pinsky’s concerns were echoed by others in Hollywood who have dealt with mental illness or addiction issues, including actor Gary Busey, who said Sheen is in a “tailspin,” and Tom Arnold, who accused those close to Sheen of exploiting his problems.

Perhaps the biggest of Sheen’s problems is that he has succeeded so well by exploiting his own reputation as the baddest of Hollywood’s bad boys. One of the most promising talents in the 1980s “Brat Pack” of young actors, Sheen starred in his first Oscar-winner (Oliver Stone’s 1986 Vietnam War drama Platoon) at a precocious age, as he pointed out in his interview with NBC’s Jeff Rossen: “I mean, c’mon bro, I won best picture at 20. I wasn’t even trying.” Sheen also starred in Stone’s next drama (Wall Street, 1987), but displayed his comic flair in hits like Ferris Bueller’s Day Off (1986) and Major League (1989).

Sheen’s star perceptibly dimmed in the 1990s, which was when he starred in his first major real-life scandal, as “Client 9” in the 1995 federal trial of notorious “Hollywood Madam” Heidi Fleiss. Sheen wrote personal checks to pay for the services of Fleiss’s prostitutes. An attorney pointed out during Sheen’s testimony that these checks amounted to more than $50,000 in a single year, to which the star replied: “Sheesh, it’s starting to add up.”

His drug and booze habits were also starting to add up. He first checked himself into rehab in 1990 and, after divorcing his first wife in 1997, publicly declared himself a born-again Christian. But in 1998, paramedics rushed to Sheen’s home in Malibu after the 32-year-old actor suffered an overdose that landed him in the hospital in critical condition. Despite all his high-profile problems, however, Sheen kept working as an actor and — in what has lately become his famous catch-phrase — kept “winning.” In 2000, he was tapped to replace Michael J. Fox in the hit sitcom Spin City and two years later married one of Hollywood’s most beautiful young actresses, Denise Richards.

Then, in 2003, Sheen landed the role of a lifetime, playing a thinly-disguised version of himself: Charlie Harper, the womanizing songwriter and live-in uncle on Two and a Half Men. The success of the CBS show is credited with single-handedly reviving the situation comedy format, which TV industry watchers had declared artistically and commercially “dead” until Sheen’s show vaulted CBS to the top of the primetime competition.

His professional success, however, did nothing to repair Sheen’s catastrophic personal life. Richards filed for divorce in 2005 and, after an attempted reconciliation, went public with devastating accusations against Sheen in a 2006 court filing: He was addicted to gambling and prostitutes, mentally unstable, prone to violence and obscene threats and — worst of all — visited online porn sites that catered to pedophilia, Richards said. Sheen did little to repair his reputation by lashing out at Richards, with whom he has two daughters, in obscenity-strewn e-mails denouncing her as a “loser” and a “sad jobless pig.” His next marriage, to actress Brooke Mueller, was brief and stormy. After marrying Sheen in 2008, Mueller gave birth to twins in 2009. On Christmas Day of that year, police arrested Sheen on a domestic-violence charge at the couple’s Aspen vacation home. Their divorce was finalized last month, by which time Sheen had already given tabloids another juicy headline: Police were called to Sheen’s room in New York’s Plaza Hotel after the actor allegedly terrorized his “date,” a 22-year-old porn performer known as Capri Anderson.

Another 22-year-old porn actress, Kacey Jordan, was at the center of Sheen’s next headline-making scandal: A January party to which the actor reportedly had a briefcase full of cocaine delivered, wrote Jordan a $30,000 check, and ended up hospitalized at Cedars Sinai Medical Center. Sheen at first agreed to another round of rehab, but then said he could kick his addictions without professional help, which led to a showdown with the producers of Two and a Half Men.

On Feb. 24, Sheen called into a nationally syndicated radio show hosted by Alex Jones, who is most famous for supporting the conspiracy-theory claim that the 9/11 attacks were a U.S. government plot. Sheen pronounced himself the victim of an “unconscionable wrong,” and called Two and a Half Men producer Chuck Lorre a “contaminated little maggot” and an “earthworm.” CBS quickly announced it was cancelling production on the show for the remainder of the season. This seemed to have pushed Sheen further into the “acute manic state” that Pinsky described. He appeared in TV interviews with two 24-year-old live-in girlfriends (one of whom was, predictably, a porn actress), ranting that he had “been kicked around” by CBS and that the network had “picked a fight with a warlock.”

It appears that his success has convinced Sheen that the rules don’t apply to him, that the rulebook “was written for normal people, people who aren’t special, people who don’t have tiger blood and Adonis DNA,” as he told NBC. But he may have finally located the limit of his own specialness. His week of demented TV interviews was followed by a rambling Saturday night Webcast (“a sloppy, self-indulgent bit of cringe theater” featuring “a posse of chuckleheads and enablers,” one critic called it), showcasing Sheen’s twisted mental condition for a worldwide audience. “All of a sudden the idea of that charming cad Charlie has started to fade,” Robert Thompson, a professor of media studies at Syracuse University, told the Los Angeles Times. After CBS cancelled Sheen’s show, Thompson said, “now it’s like he doesn’t know when to exit the stage.” Many will be amazed if the troubled actor can exit this meltdown alive, but already the laugh-track has ended.