If you mean 'Naked Lunch' Cronenberg still wrote the film i think and directed, the story is not a faithful adaptation of the novel though, but is instead a mix of some parts and ideas from the book and also parts of the authors life.
'Videodrome' is one of my favourites alongside 'Shivers' and 'Dead ringers', i think 'Existenz' is good and interesting and plays with a lot of the same themes as VD (
) although not on the same level.
I think most of his early stuff is very personal and prefer this stuff, whereas his later films seem to be him working largely around others work.
Having said that 'Dead zone', 'The Fly' and 'Dead ringers' are all based around others work, but they seem to fit in with his earlier films and themes more easily, in a way like the fly of the film they become assimilated with his unique world view.
I guess this is true also of his later films but they seem less personal to me somehow.
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MIKE: I've got it! Peter Cushing! We've got to drive a stake through his heart!
VYVYAN: Great! I'll get the car!
NEIL: I'll get a cushion.