***1/2

Danny Bonaduce, Todd Bridges, Corey Haim, Amanda Bynes, Lindsay Lohan…There is a tendency for former child stars to freak out and become disturbed, dysfunctional adults.

I have a theory as to why this happens. In addition to the normal pressures of fame, former child stars are tormented by their past. They have to deal with the horrible truth that they are loved only for what they were – not who they are now.

Unless you are as cool and talented as Neil Patrick Harris, there is no way to escape your past. The character you played when you were young will follow you around like a nagging ghost: always re-minding you that you used to be great and popular and now you’re not.

The lead character of “Birdman” – Riggan Thompson – knows how this feels. Twenty-five years ago, Riggan was an international box office star. He played the superhero Birdman in a series of block-buster action films. Now he’s just a middle aged has-been who struggles to find work.

I don’t know how they decided that Michael Keaton was the man to play an aging actor who used to be a superhero in the early 90s, but somehow Keaton pulls it off.

In “Birdman,” Riggan is taking one last shot at relevance and respect by directing and starring in a Broadway drama.

In two thoroughly entertaining hours, acclaimed Mexican director Alejandro González Iñárritu (“21 Grams,” “Babel”) takes us through Riggan’s wild emotional journey between the first preview per-formance and opening night. Riggan has to contend with his angry druggie daughter (Emma Stone), his unpredictable co-star (Edward Norton), and his pregnant girlfriend.

But mostly, Riggan has to contend with his own ego. Whenever he is alone, Riggan is tormented by his younger self dressed in the Birdman costume he wore in the movies. Birdman mocks Riggan for wasting his time performing for a thousand people when he should be making mega-hit movies like he used to.

And to add just a little dose of weirdness: when Riggan is alone, he also has super powers. He can levitate, move objects with his mind, and even fly around New York. This is absolutely never ex-plained. Some viewers will find it off-puttingly strange. I thought it was fun.

Whether or not you like the movie itself, everyone will agree that Michael Keaton is intense and spell-binding in “Birdman.” Thanks to Alejandro González Iñárritu, Keaton doesn’t have to feel like a disturbed, dysfunctional has-been. Now if only Iñárritu can find a way to make a great movie for Amanda Bynes and Lindsay Lohan.