Creepy 70s movie about teen recluse

[tokyostory]

Hello all,

For many years I have been trying to remember the title of this movie...

I saw this on TV in the early 80s.  It is probably from the mid-70s.  The story is about an nerdy and shy teenage guy who lives alone with his grandmother or older mother, who is a bit strange.  The kid is teased a lot by cool kids, but he just ignores this and goes home to the weirdness at home.  One day he has had enough, and shoves a girl who is making fun of him.  She falls back and hits her head on a rock or something and either passes out or dies.  Anyway, the boy thinks she dies and he runs home and tells his mom.  The mom is afraid of him going to jail, leaving her with no one to look after her.  So she tells him to hide.  They construct a false wall so that he can hide in some rooms of the house if anyone comes around.  They continue living like this until the mother dies.  A new family buys the house and movies in.  The boy has no choice but to keep hiding and sneaking out at night to steal their food.  The members of this family argue about this (Hey, who at the chicken I put in the fridge?) and so on.  Eventually the boy is found by the daughter of the family and she is kind to him, but I can't remember anything else.   

Anyone?  I would appreciate it SO much!

[Gerry]

I believe the movie you are looking for is BAD RONALD (1974).

http://www.imdb.com/title/tt0071186/

[Allhallowsday]

Gerry's right.  It's BAD RONALD with Scott Jacoby...

[akiratubo]

I'll confirm:  Bad Ronald.

[tokyostory]

Thank you so much!  Awesome.  Now to buy the DVD...

[RCMerchant]

 I remember that one! My dad usta play around and call me BAD RONALD,because,if I recall,the guy was an artist too,and he would paint weird pictures inside the walls of the house. And my name is Ronald. I did'nt live in the walls,though.  oh-and I never killed my grandma. (Mooo-hooo-hahaha!)