Peter Sarsgaard believes acting has helped him to become "a more fully evolved person".
The 53-year-old actor grew up in "pretty closeted parts of America" and his immediate family members were often reluctant to express their emotions.
Speaking to the Observer newspaper, Peter shared: "I lived with a lot of very sensitive people.
"Mental illness was a real thing in my house. Around those people, in those types of potentially volatile situations, you want to keep everything chill. And I’m very good at it.
"I spent a lot of my time as a kid trying to read the minds of people who didn’t know their own minds. It’s a skill I developed. I’m frequently thinking about what other people are thinking."
Peter believes he's actually developed the ability to "tell when people are lying".
The Hollywood star added: "It doesn’t necessarily mean I have a problem with them - it turns out people lie often. It’s more like information to me. I go, ‘Oh, what would make them lie about that?’"
Peter - who is married to actress Maggie Gyllenhaal - received lots of support from his extended family during his younger years.
Asked in what way mental illness was present in his childhood home, Peter replied: "Oh, I’d rather not say. But it was very much around me, all the time, 24/7.
"You know, I was supported in many ways as a kid, also. Everyone in my extended family was thinking about my welfare.
"Even to this day, I have these three female cousins … One of them thought that if she pet me enough, like, on the head, that it would make be a better person."