Minocycline and Tobacco Craving in Smokers With Schizophrenia

Nicotine dependence is high in schizophrenia; nearly three times more prevalent than the general population. In smokers with schizophrenia, the risk of all-cause mortality is doubled and cardiovascular mortality risk is twelvefold higher than nonsmokers. Many factors influence smoking in persons with schizophrenia, but predictors of craving and smoking behavior are not well established. Craving is a major contributor to smoking behaviors, and, importantly, is a predictor of relapse risk. Since craving may precede relapse, it can be advantageous as a screening tool for those attempting cessation. In addition, focusing on treatments aimed to reduce craving may lead to better therapeutic targets. Minocycline may affect craving, perhaps due to inhibition of nitric oxide (NO) formation, as NO acts as a second messenger for glutamate and dopamine receptors. NO also facilitates the effects of nicotine in the reward circuit, and blockade of NO has been demonstrated to eliminate nicotine abstinence symptoms in rats. A small study has demonstrated that minocycline reduces cigarette craving in human subjects without severe mental illness. The investigators will conduct a two-week randomized, double-blind, placebo-controlled, parallel group pilot study to investigate the effects of minocycline vs. placebo on craving and indicators of smoking intensity in smokers with schizophrenia. Participants will take minocycline up to 200 mg daily or matching placebo for two weeks. Participants will complete cigarette cue-elicited craving platforms and related assessments at baseline, and after 1 and 2 weeks of minocycline or placebo treatment.