In findings reported in a letter to the editor published online March 10 in Schizophrenia Research and reported by Medscape Medical News, the smoking cessation drug varenicline (Chantix) appears to enhance cognition in nonsmoking individuals with and those without schizophrenia. The results also showed that the drug reduced the cognitive impairment typically associated with smoking cessation in individuals with schizophrenia.
"Given the high prevalence of smoking in patients with schizophrenia and some of the associated cognitive deficits found in these patients, having a smoking cessation aid that also targets these cognitive deficits would be ideal," lead author Karolina Kozak, a PhD candidate at the Center for Addiction and Mental Health, Toronto, Ontario, told Medscape Medical News.
Cognitive deficits and rates of high smoking among schizophrenia patients are linked to dysregulated nicotinic acetylcholine receptors.
Varenicline is a partial nicotinic acetylcholine receptor agonist. Researchers reasoned it may simultaneously enhance cognition and stop worsening cognition typically associated with tobacco abstinence.
The randomized, double-blind, placebo-controlled, crossover laboratory study included a total of 30 participants, 15 with schizophrenia and 15 nonpsychiatric control persons. Participants received varenicline 0 mg, 0.5 mg, or 1 mg twice a day for 3 days in a counterbalanced manner over 3 consecutive weeks with a 1-week washout period between dose weeks in nonsmoking schizophrenia patients and nonpsychiatric control persons.
The US Food and Drug Administration recently removed the black box warning from varenicline labeling on the basis of results from the EAGLES study, which suggested that neither varenicline or bupropion was associated with an increase in neuropsychiatric adverse events compared to either the nicotine patch or placebo.
The EAGLES trial was a double-blind, randomized, placebo-controlled trial that enrolled smokers with and those without psychiatric disorders, including schizophrenia.
The investigators are now working toward testing a possible combination approach in which patients with schizophrenia receive both varenicline and some form of noninvasive brain stimulation to determine whether this might modify cognitive deficits in this patient population and simultaneously help them quit smoking.