Ryan O'Neal blames himself for his children's problems.

The 71-year-old actor - who is suffering from prostate cancer - admits he has had his own share of difficulties and feels very "guilty" that three of his four kids have ended up in rehab or prison.

Eldest son Griffin, 47, is currently two months into a 16-month sentence for driving under the influence (DUI), while daughter Tatum recently left rehab after suffering a "cocaine relapse." The pair's half-brother Redmond - whose mother was late actress Farrah Fawcett - is currently seeking court-ordered treatment for heroin addiction.

"Look, I don't give myself a break. I had four children. Only sportscaster Patrick's OK. Griffin's in prison. Redmond, who feels terrible guilt, is in rehab. Tatum, rehab. I had my own problems. Is all this my fault? I guess, yes. When his mother was dying I paid sheriffs $800 overtime to bring Redmond in chains. I keep all her mementoes in a safe to give him someday," he said.

Ryan is preparing to release his autobiography, Both of Us: My Life With Farrah, chronicling his time with the Charlie's Angels actress - who died of cancer in June 2009 - and he admits their relationship was not perfect, mainly due to his own insecurities.

"She and I were together on and off 18 years, and I always kept journals. Lots of information. Every night I wrote in a diary. Ours was a wonderful but imperfect love. I'm a semi-nice guy, but I was jealous, insecure, everything you don't want in a man. Most times I don't like me. It's all I talk about now," he told The New York Post.