Differential effects of cocaine, alcohol, and nicotine dependence on olfactory evoked potentials.

Olfactory evoked potentials (OEP) were elicited by odorous and nonodorous stimuli in 50 adult subjects: 26 subjects with histories of either cocaine (n = 19) or alcohol (n = 7) dependence, 10 with histories of nicotine but no other drug dependence, 2 with clinical anosmia of peripheral origin, and 12 subjects without drug or olfactory disorders. The presentation of nonodorous stimuli (i.e. a nasal air puff) did not elicit OEP component amplitude and latency differences among the groups. However, the presentation of odorous stimuli elicited a significantly smaller P1 component in the cocaine-dependent and alcohol-dependent groups than in the normal control and nicotine-dependent groups. The P1 amplitude deficit in the cocaine-dependent group is consistent with case report data associating cocaine use with lesions of the peripheral and/or central olfactory apparatus.