"I've been through the worst and came out the other end and survived it," she says in a new profile.
The former child star, who famously went through a very public breakdown in 2013, looks amazing in a blazer, dress shirt and denim for the issue, where she also opened up about her drug use, sobriety and those infamous tweets.
Telling the publication she's now four years sober, Bynes said her erratic behavior was, "truly," drug-induced. "Whenever I got off of [drugs], I was always back to normal," she said.
The now 32-year-old actress said she first began using drugs when she was 16, starting with marijuana. "I didn't get addicted and I wasn't abusing it," she continued, "and I wasn't going out and partying or making a fool of myself ... yet."
She would later do molly and ecstasy, and tried cocaine three times but "never liked it." She maintains she's never done meth or heroin.
Bynes explained that she first went into a "deep depression" when the 2006 movie "She's the Man" was released. "I didn't like how I looked when I was a boy," she explained. "I've never told anyone that," she added, saying that her boyish appearance "just really put me into a funk."
She then got hooked on Adderall, which she says she "definitely abused" to lose weight, faking ADD symptoms for a prescription.
Her addiction to Adderall led to her pull out of the 2010 movie, "Hall Pass," as her body issues began spiral out of control. When her next film, "Easy A," was screened, she said she "literally couldn't stand my appearance" or her performance in the film.
"I was absolutely convinced I needed to stop acting after seeing it," she explained. "I was high on marijuana when I saw that but for some reason it really started to affect me. I don't know if it was a drug-induced psychosis or what, but it affected my brain in a different way than it affects other people."
She would announce her retirement on Twitter -- something she now says was "stupid" -- before she wound up just "getting high, watching TV and tweeting."
"I'm really ashamed and embarrassed with the things I said," she explained of her tweets, which famously included one aimed at Drake we won't repeat here. "I can't turn back time but if I could, I would. And I'm so sorry to whoever I hurt and whoever I lied about because it truly eats away at me."
Looking back now, she acknowledges that drugs made her "a completely different person," adding that she would "never feel, say or do any of the things that I did and said to the people I hurt on Twitter."
"I don't miss it because I really feel ashamed of how those substances made me act," she said. "When I was off of them, I was completely back to normal and immediately realized what I had done —- it was like an alien had literally invaded my body. That is such a strange feeling."
These days she's currently enrolled at Fashion Institute of Design and Merchandising in Los Angeles, where she's about to graduate with an Associate's of Art degree in Merchandise Product Development. She also wants to return to acting.
In closing, she added, "I have no fear of the future. I've been through the worst and came out the other end and survived it so I just feel like it's only up from here."