filmmaker's childhood friendship affected by adult onset of schizophrenia in friend

Hello.

The film that you're looking for is probably "My Friend Paul" (1999)
by Jonathan Berman.

Read this description from New York Foundation for the Arts:

"My Friend Paul is an exploration of friendship, using video making as
a therapeutic tool. The film examines the relationship between Berman
and a childhood friend who, for a time, robbed banks. Berman describes
the film as an "edgy 'video diary' exploration of mental illness and
its affect on family and friends. Since we made Super 8 'epics' as
kids, with Paul as the star, the relationship continues, as the
'making of' aspect, and Paul's undeniable charisma and charm take over
the narrative. The process of creating My Friend Paul is equally a
struggle for narrative control and a cathartic rejoining of opposites
bound together by the power of image making."
http://www.nyfa.org/artists_fellowships/af_fellows2000_video.htm

Also see an extensive description from Independent Television Service:
http://www.itvs.org/myfriendpaul/story.html

The film has been shown at numerous film festivals. It has also aired
on public television and the Sundance Chanel:
http://www.sundancechannel.com/film_finder/index.php?startingLetter=m&offset=40

A videocassette is available from Fanlight.com, but it's a little on
the expensive side ($225):
http://www.fanlight.com/catalog/films/298_mfp.htm

search strategy: mental illness, childhood friend, film

I hope this helps.

great answer and very prompt - thanks so much