Effects of cigarette smoking and nicotine nasal spray on psychiatric symptoms and cognition in schizophrenia.

Schizophrenic patients have among the highest rates of smoking of any group of patients. Previous studies have identified psychophysiological and potential nicotinic receptor abnormalities which may be associated with this phenomenon. The effects of acute smoking or acute administration of nicotine nasal spray, after smoking abstinence, on negative symptoms and neurocognitive function have been less extensively studied in experimental designs. This study investigated the effects of smoking of high nicotine or denicotinized cigarettes, and receiving active or placebo nicotine nasal sprays, on positive and negative symptoms and cognitive functions in schizophrenic patients. The study utilized a placebo controlled crossover experimental design with pre- and post-drug evaluations on each experimental day. Smoking high nicotine cigarettes decreased negative symptoms more than denicotinized cigarettes, but smoking neither cigarette changed scores of positive symptoms, anxiety, or depression. Active nicotine nasal spray did not differentially decrease negative symptoms compared with placebo, but did improve performance on a spatial organization task, and tended to improve some measures of verbal memory and two-choice reaction time in schizophrenic patients. Both high and denicotinized cigarettes improved performance on the spatial processing task, but there was no statistically significant differential drug (Cigarette type) effect. These results suggest that acute smoking of cigarettes may transiently decrease negative symptoms in patients with schizophrenia, but it is unclear whether this effect is attributable to nicotine, other components of cigarettes, or the act of smoking. Nicotine nasal spray may modestly improve some selected aspects of cognitive function in schizophrenia.