Linda Hamilton has spent "hundred of thousands of dollars" on her mental health.

The Terminator actress has spoken openly in the past about her struggles with depression and bipolar disorder but after decades working on herself, she feels she has finally found "true balance and steadiness" and knows how to cope with bad days.

She told People magazine: "Nobody ever thinks that I'm going to struggle. [They think] I'll be fine -- 'It's Linda Hamilton'.

"I have found just true balance and steadiness in my day and in my life. And I also can activate all of the safeguards that I learned from 20 years of therapy.

"If I'm having a bad day, that doesn't mean that my behaviour has to be bad or that my actions [have to be].

"I'm experienced enough now to go, 'Well, [doing] that might sound good right now, but really in an hour, are you going to want to have done that?'

"I can apply the brakes because I spent years and years and hundreds of thousands of dollars to get better."

The 68-year-old star has found contentment by focusing on other people more than herself.

She said: "I never think about myself. That was the first 40 years.

"And when I got the balance, I made a deal with myself that it would never be about me again. And it hardly ever is. It's just not about me.

"I want to pitch in, help people, make people laugh, make my house beautiful. The normal things. Love my dogs to death. [And] it all makes me very happy."

Linda joked she was a "hot mess" for the first 40 years of her life and urged those struggling with their own mental health to keep going.

She said: "People just can't give up on themselves. That's the thing. It's just keep looking until you find your way through it. I'm living proof that it can be done. And I was a hot mess for the first 40 years."

The Stranger Things actress revealed in 2004 she had both depression and bipolar disorder, but it took her a long time to understand why she was experiencing intense mood swings.

She said: "I would say [I had] 20 full years of symptoms, not counting my childhood. From 20 to 40. I call them my lost years.

"My first husband [actor Bruce Abbott] said you have the most incredible joy and the most incredible sorrow that goes with it. Without giving it a name, he had pretty much summed it up for me."