For every success story, there are a hundred failures like CORY MONTEITH warns former heroin addict.

On the first anniversary of “Glee” star Cory Monteith’s drug overdose death nears, a former heroin addict says a toxic one-two punch of shame and failed rehab is killing Hollywood stars.

“Cory Monteith was shamed to death. The guilt of having a relapse essentially killed him,” ex-junkie Tracey Helton Mitchell told The National ENQUIRER.

“He probably felt he couldn’t call anyone, because everyone has expectations of the addict – that you go into abstinence-recovery and that’s it. [You don’t] use, [anymore],” she said. “But the research shows that’s not what happens.” Tracey, 44, kicked dope after filming the gritty 1999 documentary, “Black Tar Heroin: The Dark End of the Street.”

The experience made Tracey realize how difficult it is to get sober while in the public eye and how the stress of fame can crush an already fragile celebrity personality.

After a stint in rehab, celebrities – who face financial pressures and potential damage to their image – can be pushed “to a place where they don’t feel they have anyone to talk to, so using becomes an option again,” said Tracey.

Monteith, 31, is a prime example, she said. Just two months after leaving rehab, the actor and musician was tragically found dead from a heroin overdose in a Vancouver hotel room on July 13, 2013. Sadly, heroin has recently claimed the lives of two other celebrities.

After being sober for 23 years, Oscar winner Philip Seymour Hoffman, 46, was found dead of a heroin overdose in February. Two months later, the lifeless body of British TV presenter Peaches Geldof, 25, was found in her bed in Kent, England.

“I think heroin in particular appeals to smart, creative people because it numbs your sense of not fitting in,” said Tracey, whose addiction left her homeless and working as a prostitute on the streets of San Francisco in the ’90s.

Based on her insider’s view of drug addiction, she believes addicts must spend a lengthy amount of time in rehab to recover.

“People go in and out of rehab over and over because 28 days is not long enough,” said Tracey, a mother of three. “How many times have we seen Lindsay Lohan go through short-term rehab in the past few years? We call it ‘spin-dries,’ and they don’t work.”