Psychology Paper Help- Film Analysis?

[Sana]

I have to analysis a film and I chose Garden State.
-Psychological foundation (substance abuse, child abuse etc)
-Analysis of main character (how issue developed, effects, if it was resolved)

If yall could help me that would be great! Im just having so much trouble on this for some reason. And also I didn't realyl understand the significance of the gas thing still in the gas tank of his car?? And if you have another movie that you think would be better to write on that would be cool too but it has to be fairy recent. Thanks in advance!