Effects of transdermal nicotine on episodic memory in non-smokers with and without schizophrenia

Abstract

Rationale: Nicotinic agonists may improve attention and memory in humans and may ameliorate some cognitive deficits associated with neuropsychiatric disorders such as schizophrenia.

Materials and methods: We investigated the effects of a single dose of nicotine on episodic memory performance in 10 adults with schizophrenia and 12 healthy controls. Participants were nonsmokers in order to avoid confounding effects of nicotine withdrawal and reinstatement on memory. At each of two study visits, participants performed a test of episodic memory before and 4 h after application of a 14-mg transdermal nicotine (or identical placebo) patch in counterbalanced order.

Results: Compared with placebo, nicotine treatment was associated with more rapid and accurate recognition of novel items. There was a trend for a treatment by diagnosis interaction, such that the effect of nicotine to reduce false alarms was stronger in the schizophrenia than the control group. There was no effect of nicotine on accuracy or reaction time for identification of previously viewed items.

Conclusions: These data suggest that nicotine improves novelty detection in non-smokers, an effect that may be more pronounced in non-smokers with schizophrenia. Because memory deficits are associated with functional impairment in schizophrenia and because impaired novelty detection has been linked to the positive symptoms of schizophrenia, study of the effects of chronic nicotinic agonist treatment on novelty detection may be warranted.

Figures

Fig. 1

a Nicotine effect on false alarm rate in an episodic memory task. Main effect for nicotine, F(1,17)=8.47, p<0.01. Treatment × group interaction, F (1,17)=3.13; p=0.095. b Nicotine effect on hit reaction time for novel items. Main effect of nicotine, F(1,18)=9.11; p=0.007