The new movie "Black Swan" explores the dark side of ballet with Natalie Portman and Mila Kunis playing a dance of good and evil to the extreme. It's an intriguing thriller, telling a twisted tale of what happens when a young woman starts to believe the defeatist voices that dance in her head. Portman's character, Nina, wins the lead in "Swan Lake," only to become so driven by her desire for perfection that she can't live a real life. Kunis's character, Lily, more the black swan to Nina's virginal white, is full of desire, passion and living a life uncontrolled. She becomes Nina's alternate for the role, and from there on out it's a mind game. Is it Nina's inner voice that leads to her destruction or the others, be it the threat of her foe or the challenging ideals of being a prima ballerina?

This movie is a fantasy, but the reality is that many young women have a rich fantasy life in their head. When something goes askew, the mind hits its own play button and a self-defeatist soundtrack starts running: "I'm not good enough, smart enough, pretty enough. I'm not enough." Or in the case of Natalie Portman's character, "I'm not perfect."

Twenty-somethings today are particularly susceptible to self-doubt, given the millennial desire to achieve and meet the expectations of their parents. Fortunately, a lot of 40-something women I've interviewed have learned to turn off the negative voices. Here's their advice on how to change the tune:

Learn to Be Wrong

As with the badass ballerina, one way to get rid of those voices is to let go of trying to be perfect. Make mistakes. Do the wrong thing. To quote the movie, "perfection is not just control, it's also letting go." Or more appropriately, "it's better to be wrong than perfect." Some young women choose not to participate if they aren't perfect. Recently a friend of mine was worried that her daughter would try every sport or activity but would drop out the moment she wasn't the best. The problem is, you can't drop out of life, so get used to not being perfect.

Similarly, early in my career I would hesitate to say something in a meeting for fear that it wasn't "right" and that I'd look stupid in front of my boss. Thing is, in your 20s you're allowed to say stupid things. It's probably the fresh thinking that your boss is looking for even if it's not the "perfect" answer.

I never let my kids quit anything until they finish this season even if they hate it because without "stick-to-it-iveness" you're pretty much screwed. All your life you will come up against obstacles and you have to find a way around them whatever they are, whether it's emotional or real. (40-something, Detroit)

Learn to Be Present

Other 40-somethings shift from negative to positive thoughts through mindfulness. Twenty-somethings are great at instant gratification, but that's different from living in the moment.

In my 20s I was too much in my head. I learned from yoga how to stay present. How not to get caught in the unproductive soundtrack in our heads. There's this soundtrack that's not true. "I can't have this, he's too good for me. I'll never be able to do that." You say crazy things to yourself. Things you'd never say to a friend, or even your enemies. I would tell a 20-something to spend a lot of time on mindfulness practices because if you can keep your mind focused off of the negative thought patterns, you can avoid a lot of suffering. (40-something, New York)

Find a Mantra

I recently had lunch with two friends, both looking for jobs. One woman's internal soundtrack kept saying, "What did I do wrong that I didn't get called back for that job?" The other woman had entirely different playback: "What the hell is wrong with those people?" This same woman shared an anecdote about how she uses this and other mantras to keep herself positive.

One time I was going to visit a friend and I had a very long, tough drive. I said to my husband, "I hope I'll be okay driving." He was like. "Of course you'll be okay, you are an adult." That resonated with me so much. Of course I will be ok. I am an adult. I know how to drive. I've been driving since I was 16. Why am I building up such a false fear? Why am I making this into some ridiculous barrier when it isn't a barrier at all? It's my mantra whenever I get weirded out about doing something. "Of course you can. You are an adult." (40-something, New York)

Stop Comparing

It's hard to do in your 20s. You are exploring who you are and looking to others for cues. But don't confuse trying on different personas with trying to be someone you're not.

There's always someone who is doing more, who is prettier, thinner, smarter, wealthier and it's very easy to get caught up in that. But there's also someone who's not as smart, not as attractive. So what? If you understand that things can be important without being serious, then you don't take yourself so seriously. Then it's easier to not compare. If you focus on living your best life, It's really impossible to get caught up in the comparisons. (40-something, New York)

And lastly, as anyone who sees the movie will relate to...

Stop Listening to Your Parents

Many young women still feel conflicted about what their parents want them to do. The 20s are your time to stand your ground.

I think if you're in your 20s and you're still listening to what your mom said you need to get quickly onto the couch of a therapist because it's time to separate. It was time probably five or six years ago. Your mom and dad, I'm sure they have good advice but they already got to do their stuff and now it's your turn to do your stuff. Stay true to yourself and be willing to admit it when you blew it because you probably will. (40-something)

Negative voices in your head make for good movies. But don't think that the movie playing in your head is real.