Effects of Nicotine Replacement Therapy and D-cycloserine on Nicotine Treatment Seekers

The investigators previously developed a cigarette cue extinction treatment (CET) procedure in non-treatment seeking volunteer smokers in our nicotine laboratory. The goal of Cue Extinction Treatment is to un-pair a behavioral or autonomic response from the stimulus that triggers it. This is accomplished through repeated exposure to that trigger, while removing the patient's ability to act out the conditioned response. In the present study, the trigger is a lit cigarette, and the response the investigators seek to un-pair is cigarette craving. In the procedure the investigators have previously developed and intend to use again, the participant is shown a pack of his brand of choice cigarettes. The researcher removes a cigarette from the pack, lights it, and asks the participant to hold the cigarette without smoking it for 90 seconds. This procedure is repeated seven times over the course of a six-hour lab session. The investigators hope to boost the clinical response to smoking cue exposure therapy in quitters on NRT (nicotine replacement therapy) pretreatment by pharmacological augmentation with the partial NMDA receptor agonist D-cycloserine (DCS). Behavioral extinction training is a form of learning that may be modulated by NMDA receptor mediated glutamate transmission. The study's main hypothesis is that the partial NMDA receptor agonist D-cycloserine (DCS) facilitates cue exposure training and may prevent relapse to smoking. The aim of the proposed study is to assess whether DCS-facilitation of cue-exposure therapy improves abstinence among smokers on the nicotine patch seeking treatment. Development of an effective treatment strategy to enhance the effectiveness of NRTs would have a direct and significant positive impact on public health.