State-dependent learning effects with a combination of alcohol and nicotine.

An experiment was carried out to investigate whether nicotine ingestion (via cigarette smoking) interacted with alcohol (vodka and tonic) in its effect on state-dependent learning (SDL) in humans. On Day 1 of the 2-day experiment 24 subjects were required to learn a simple route map previously found to be SDL sensitive with alcohol. All subjects ingested 0.66 g alcohol/kg body wt. and smoked two medium tar cigarettes (average nicotine content 1.4 mg). Twenty-four hours later, subjects attempted recall under one of the following drug states; (i) alcohol and nicotine (A + N); (ii) alcohol and smoking placebo (A + O); (iii) Nicotine and placebo drink (O + N); and (iv) no drugs (O + O). Highest recall scores were observed in the A + N subjects, with O + N and O + O subjects recalling the least. A + O subjects had intermediate recall performance. Thus the combination did produce a clear SDL effect, with alcohol possibly contributing the major influence.