The Ironic hitmaker admits she still struggles with thoughts of ending her life and believes much of her depressive nature comes from being highly sensitive.
After making her admission about being saved by therapy, she was asked if she was suicidal and told The Guardian newspaper: "All the time. I still struggle with it. I have an anxious, depressive tendency. Those who are sensitive are much more susceptible to their environmental information.
"If you put a highly sensitive person in an environment where they're brow-beaten or reduced, they'll basically want to kill themselves. It's the worst. If you put a highly sensitive person in an environment where they're supported, championed and listened to, they thrive."
The 51-year-old star - who has Ever, 14, Onyx, nine, and five-year-old Winter with husband Souleye - believes couples therapy is hugely important in her marriage.
"I'm a huge couples therapist person. I have been for ever," she said.
But Morissette insists any therapist she and Souleye work with must be trauma-informed and addiction-informed.
"I can't be supported by someone who doesn't look through those lenses," she said.
The Thank U singer has struggled with addictions to work, love, sex and shopping, to which she takes a "Whac-a-Mole" approach of tackling whenever one issue or another pops up.
"I call addiction 'relief-seeking measures that kill you eventually'," Morissette said.
"There are some people who would get very mad at me for implying at all that (sobriety) is nuanced. Because for those of us who were drinking at seven in the morning, well there's nothing nuanced about that.
"So, I guess it depends. For me, it's whichever addiction is bringing you to death very fast. Which one is it? Which one's ruining your relationships?
And then there's the Whac-a-Mole approach, which is, 'OK, I've stopped not eating. And now I'm working my ass off. Oh, yeah, and I took a few too many pills.' The Whac-a-Mole, that's what we have to keep an eye on."
The singer finds being a workaholic particularly tough because it is a quality often celebrated.
"If I said, 'Oh, I did heroin till four in the morning and totally blacked out', people would be like, 'Oh s***. B**** needs some help.'
"But if I said, 'I've been working my f****** a** off for this deadline and I finished at 4.15am,' people would be patting my back and be, like, 'Good work, girl.' It's equally corrosive. Because any addiction, if we keep going with it, we're dead. It is great for 20 minutes, then you're dead."
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