Mental illness, which the National Alliance on Mental Illness (NAMI) defines as "a condition that affects a person's thinking, feeling or mood," has long been stigmatized, and has often been a source of shame for people who struggle with conditions including anxiety, depression and bipolar disorder. But according to NAMI, nearly 20% of adults in the U.S. alone (or 1 in 5 adults) suffer from a form of mental illness.

In an effort to encourage others to speak about and seek treatment for their mental health issues — as well as cope with their own — many celebrities have publicly opened up their experience with it, from pop stars like Demi Lovato to actors like Deadpool star Ryan Reynolds.

Click through the gallery above to see a collection of stars who have addressed their battles with depression, anxiety and other mental illness openly.

Celebrities Who Opened Up About Mental Health

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