Mischa Barton, star of "The O.C." claims her bizarre mental breakdown was caused by drugging with a date rape drug called GBH while partying. The actress warns young girls to beware of drinks being accidentally doped by Ecstasy or similar substances. But many wonder which came first, the drugs or the alcohol? Others wonder if substance abuse is behind her yo-yo weight loss. The actor (who plays Marissa Cooper), was arrested for DUI and spent time in a mental hospital.

GHB blamed for Mischa Barton's odd behavior

Barton says that after a night of drinking to celebrate her birthday, she began to feel odd.

Her behavior became erratic so she checked herself into Cedars-Sinai Hospital. But video footage tells another story. Barton was filmed hanging over a neighbor's fence and screaming incoherently. She was hospitalized for a mental breakdown. Emergency room physicians found GHB (gamma-Hydroxybutyric acid) which is a naturally occurring neurotransmitter. It also has psychoactive properties similar to certain mushrooms. It is called a date rape drug, like Ecstasy or Rohypnol, because it lowers inhibitions. Slipped into a drink, GHB is undetectable and can induce unconsciousness.

Mischa Barton's claims polarize folks

Some scoffed that with her history of drug abuse, she was just using the date rape drug claim to excuse drug presence.

Some question gaps in her story concerning how she got to the hospital. One commenter said she was drugging and someone gave her a drink. Others chimed in to defend Barton, saying how common and easy it is to spike drinks at bars and nightclubs. It might not even be for the purpose of sexual assault. Randomly tainting drinks is not unheard of, and it not only women who are drugged.

Men have complained of getting slipped a "Mickey Finn" as a prank on Facebook and social media. How the drugs affect people depends on how much they've eaten, and what other drugs, like weight loss supplements, they are taking.

Mischa Barton shows anorexia weight loss

After several years on "The O.C." Barton's career nosedived.

A stint in a psych hospital, legal, and financial troubles led to the celebrity showing weight gain. It wasn't obesity but after anorexia-like slenderness, folks noticed. Mischa admitted to constant weight battles and hinted at an eating disorder. Then, she began to lose weight, crediting a fat binder called Proactol XS. In fact, Barton became a spokeswoman for the mushroom-based weight loss drug. Mischa also advocates vaping and represents VAPESTICK, an e-cigarette brand. Many wonder if substance abuse caused her meltdown.