Glad there is finally a discussion going on about something related to my profession. I want to say that I am not suggesting anything, but simply systematizing things from the point of view of the modern psychology and psychiatry to such phenomena:
There is a great trio that epitomizes intrusive states:
Obsessions - intrusive thoughts
Compulsions - intrusive behavior.
Phobias - intrusive fears.
All intrusive states are neuroses, which are an intermediate state between psychosis and a mental state corresponding to normality.
Addictions are quite different and are divided into chemical and non-chemical addictions. When a person is addicted, he or she feels an unbearable urge to do something (smoke a joint or play video games, suit yourself). Subsequently, when performing the act, the person may experience feelings ranging from relief, to ecstasy (depending on the stage of addiction).
P.S. Kudos to Duh for the suggestions, I think they are extremely appropriate.
P.P.S. The interpretation and explanation of these states are purposely simplified for the commentators' understanding.