Mindfulness for smoking-cessation : a behavioural and neurophysiological study.
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
In recent years the effectiveness of skills-training, the mainstay behavioural treatment for smoking-cessation, has been questioned, providing a rationale to investigate alternative treatments. We hypothesised that mindfulness, an emerging treatment for addiction, can reduce smoking by decreasing drug-related processing bias and remediating deficits in inhibitory control. Our study tested this in 37 smokers and 12 non-smokers at baseline, and at a 1–2 month follow-up after smokers used a 22-day long mindfulness-based smoking-cessation programme called Craving to Quit (C2Q), which was delivered via smartphone. Poor inhibitory control was defined as lower accuracy and lower amplitudes of the event-related potentials (ERPs), N2 and P3, elicited in a Go/NoGo task. Drug-related processing bias was defined as higher P3 and late positive potential (LPP) ERP amplitudes elicited for smoking images relative to neutral images, during an image slideshow task. The task also expected to show normal responding to pleasant and unpleasant images in smokers, shown by increased P3 and LPP amplitudes, compared to neutral images. The study replicated a deficit in inhibitory control among smokers (reduced NoGo N2) but found no smoking-related processing bias at baseline. Unexpectedly, the study revealed blunted P3 amplitudes in response to all picture categories, except unpleasant, in smokers at baseline. We suggest that this may be reflective of an anhedonic state during acute withdrawal. A large non-compliance rate led to a follow-up comparison limited to 11 smokers and 11 non-smokers. Although smokers showed significant reductions in average number of cigarettes smoked/day, they showed no change in self-reported craving. They also showed no change in processing to any of the picture categories. We suggest that limitations due to filtering hampered our ability to detect what appeared to be an increased late LPP at frontal electrodes for all categories, potentially reflecting increased awareness from mindfulness. Although smokers showed significantly lower NoGo accuracy compared to non-smokers at follow-up, they also showed increases in a neural marker of inhibitory control (NoGo P3). Further research is required to determine whether this reflects neural improvements preceding changes in behaviour, or reflects a compensatory increase in neural activity during a quit attempt. Overall, our study suggests that mindfulness-treatment can reduce smoking when delivered via smartphone but we cannot confirm whether this is related to mindfulness, the app, being in the study or a quit attempt. Further research comparing C2Q to an alternative intervention group, is needed to further explore C2Q’s mechanisms of action and whether it shows benefit over other apps.