Megan Fox. (AP Files)

Actress Megan Fox has a secret she's been hiding from her legions of fans - she suffers "bouts of schizophrenia."

The Transformers star admits she has struggled with mental health problems since her youth, and, although she hasn't been officially diagnosed, she is convinced she shows symptoms of the serious psychiatric condition, which often torments suffers with auditory hallucinations, paranoid delusions and social dysfunction.

The 23 year old reveals she has spent years meticulously studying the life of movie legend Marilyn Monroe, who died of a drug overdose at the age of 36 - because she fears her own problems may lead her to a similar end.

She tells Wonderland magazine, "I basically read every book ever written about Marilyn Monroe. I could end up like that because I constantly struggle with the idea that I think I'm a borderline personality - or that I have bouts of mild schizophrenia.

"I definitely have some kind of mental problem and I haven't pinpointed what it is."