Nov. 27 (UPI) -- Amanda Bynes says her "strange" behavior of years past was caused by drugs.
The 32-year-old actress recalled in an interview with Paper magazine published Monday how her drug use influenced her bizarre tweets and led to a "really dark, sad world."
"I started smoking marijuana when I was 16," she shared. "Later on it progressed to doing molly and ecstasy. [I tried] cocaine three times but I never got high from cocaine. I never liked it ... [but] I definitely abused Adderall."
Bynes said her drug use affected her performance on set, making her "scatterbrained" and unable to focus on her lines. It also had a strange effect on her perception and self-image, which led to her abrupt retirement.
"I literally couldn't stand my appearance in [Easy A] and I didn't like my performance," she said, referencing her 2010 movie with Emma Stone. "I was absolutely convinced I needed to stop acting after seeing it."
The former Nickelodeon star said she retreated from the spotlight and "got really into" her drug use. She stayed at home "getting high, watching TV" and tweeting bizarre messages about celebrities.
"I'm really ashamed and embarrassed with the things I said. I can't turn back time but if I could, I would," the star said. " And I'm so sorry to whoever I hurt and whoever I lied about because it truly eats away at me. It makes me feel so horrible and sick to my stomach and sad."
Bynes today has been sober nearly four years and will receive her associate degree at the Fashion Institute of Design and Merchandising this month. She warned those struggling with substance abuse that drugs "can really take a hold of your life."
"Everybody is different, obviously, but for me, the mixture of marijuana and whatever other drugs and sometimes drinking really messed up my brain. It made me a completely different person," the actress said. "Be really, really careful because you could lose it all and ruin your entire life like I did."
"Truly, for me, [my behavior] was drug-induced, and whenever I got off of [drugs], I was always back to normal," she added.