monomania
noun
[ mɒnə(ʊ)ˈmeɪnɪə ]
• exaggerated or obsessive enthusiasm for or preoccupation with one thing.
• "she has an obsession with the drug that verges on monomania"
Similar:
obsession,
fixation,
idée fixe,
ruling passion,
consuming passion,
mania,
compulsion,
fetish,
preoccupation,
hobby horse,
bee in one's bonnet,
thing,
