NASHVILLE -- The apparent suicide of country singer Mindy McCready makes her the fifth troubled cast member of the "Celebrity Rehab" reality TV series to die since appearing on the show, stoking rumours of a curse and a debate about the show's helpfulness.

Criticism of TV host Dr. Drew Pinsky spread on the Internet almost as quickly as news of McCready's death.

While many noted that Drew took on hard cases, others rendered stark judgment. Singer Richard Marx on Twitter compared Pinsky to Dr. Jack Kevorkian, the so-called suicide doctor who said he assisted in the deaths of about 130 gravely ill people: "Same results."

Marx backed off later Monday, saying the crack went too far. But he restated his thoughts in a way that summed up much of the reaction in the first 24 hours since the 37-year-old McCready's death Sunday afternoon in Arkansas.

"It is, however, my opinion that what Dr. D does is exploitation and his TV track record is not good," Marx wrote.

VH1's "Celebrity Rehab with Dr. Drew" is not currently on the air. Pinsky switched his focus to non-celebrities in Season 6 last fall and changed the title to "Rehab." The show spawned two spinoffs, "Sober House" and "Sex Rehab."

Season 3, shot in 2009, featured McCready, former NBA star Dennis Rodman, actors Tom Sizemore and Mackenzie Phillips, former Hollywood madam Heidi Fleiss and a handful of lesser known celebrity types.

"My heart is breaking. Rest in peace dear friend," Phillips said Monday on Twitter.

McCready was a sympathetic character on the show and appeared to be far less damaged than her fellow cast members, some of whom experienced fairly graphic symptoms of opiate withdrawal in front of the cameras. McCready suffered a seizure while on the show, further endearing her to Pinsky and the others.

She said in a 2010 interview with The Associated Press that she initially turned Pinsky down.

"But Dr. Drew said something to me that just mowed me over literally, just floored me," she said. "He said, 'You've been being treated for the symptoms of what's wrong with you, not the problem. And you're going to have to put your family aside for a moment, put their feelings aside for a moment and worry about you because if you don't get better, it doesn't matter what your family thinks. You're not going to be there anymore."'

Pinsky diagnosed her with "love addiction" during the series' run and called her an "angel" in the finale. In an interview with The Associated Press several months later, he said McCready had a good shot at recovery if she remained in treatment.

Three years later, she's dead of an apparent self-inflicted gunshot to the head. McCready walked away from treatment several days ago after her father asked a judge to intervene. Her body was found on the front porch of a home she shared with longtime boyfriend David Wilson, who appears to have killed himself in the same spot last month. Wilson was the father of McCready's youngest son.

Pinsky wasn't immediately available for comment, his publicist said, but he issued a statement Sunday night that noted he'd spoken with McCready recently.

"She is a lovely woman who will be missed by many," the statement said. "Although I have not treated her for a few years, I had reached out to her recently upon hearing about the apparent suicide of her boyfriend and father of her younger (child). She was devastated. Although she was fearful of stigma and ridicule she agreed with me that she needed to make her health and safety a priority. Unfortunately it seems that Mindy did not sustain her treatment."

A lack of continued treatment also appears to have led to the deaths of McCready's Season 3 castmates Mike Starr, bassist for Alice in Chains, and Joey Kovar, a "Real World" participant. Los Angeles riots spark Rodney King and actor Jeff Conaway also have passed away. Starr and Kovar overdosed and King was found dead in his pool with alcohol and marijuana in his system. Conaway was initially thought to have overdosed, but died of pneumonia and an infection.

Bob Forrest, a chemical dependency counsellor who appeared on Season 3 of "Celebrity Rehab" and continues to work with Pinsky, said a discussion about mental health and substance abuse issues is important. But attacking Pinsky has only distracted from the real issues.

"Regardless of your feelings about how we do it with the TV show, calling Dr. Drew 'Dr. Kevorkian,' what kind of dialogue is that?" he said. "It's a good headline. We're going through a growth spurt in regards to who we are as a country. I really feel there's something going on in America beyond Mindy McCready's death."

The most recent figures from the Centers for Disease Control and Prevention show there were 38,364 suicides in the U.S. in 2010 -- an average of 105 a day. Thirty-three per cent of suicides tested positive for alcohol in 2009 and 20 per cent for opiates, including heroin and prescription painkillers.

Experts said there is no good data on suicides after rehab in part because treatment programs vary widely and it can be unclear if an overdose is intentional. But a patient with substance abuse problems is at higher risk for a suicide attempt.

Dr. Sharon Hirsch, an associate professor in the University of Chicago's Department of Psychiatry and Behavioral Neuroscience, says patients can get trapped in the yin and yang of addiction. She was not familiar with McCready's case, but noted people abusing alcohol or drugs have a lower impulse control. And their lows when they're off drugs become more difficult to overcome, also lowering their resolve.

Pinsky's shows drew attention to the struggle. But did they help patients? Pinsky has taken an interest in cast members after the shows end and referred them to continuing treatment. But ultimately Hirsch wonders who was on call the last time McCready pondered killing herself.

"One of the key components of any treatment is to talk confidentially with your treatment provider about every aspect of what is going on with you, to be able to get the best care you can," she said. "I just don't know how that could occur in the context of an internationally televised show. And so it would be difficult for me to envision it as a complete treatment program. ... It just really strikes me as entertainment and not as treatment."