Mentions of Cronenberg's "Spider" made me think of films / books that simulate psychosis, not just preesenting it thematically but effectively bringing you into that state of a faulty consciousness. Other examples that come to mind..
Kafka, The Metamorphosis
Evelyn Waugh , The Ordeal of Gilbert Pinfold
Polanksi, The Tenant
Terry Gilliam, Tideland (more about a child's imagination but presents allot of parallels between a childs overactive imagination and a psychotic state imo)
Adrian Lyne , Jacobs Ladder
Kafka, The Metamorphosis
Evelyn Waugh , The Ordeal of Gilbert Pinfold
Polanksi, The Tenant
Terry Gilliam, Tideland (more about a child's imagination but presents allot of parallels between a childs overactive imagination and a psychotic state imo)
Adrian Lyne , Jacobs Ladder