Mindfulness and Stress - a Randomised Experiment

We conduct a randomised controlled trial of an online course in mindfulness. Previous research has found evidence that mindfulness reduces stress; however, few studies have been carried out on non-clinical populations that have not self-selected into or paid for treatment. Our sample consists of 139 students with no pre-existing medical conditions and no prior information on the experiment and treatments. Half of them are asked to follow a four-week mindfulness training, while the other half are asked to watch a four-week series of historical documentaries. We follow participants for five consecutive weeks, with an additional post-intervention session five months later. We evaluate the effects of the mindfulness program on measures of chronic stress, and on the response to stressful situations, measured by cortisol and self-reports. We find strong evidence that mindfulness training reduces perceived stress, as measured by the Perceived Stress Scale. However, the physiological responses to an acutely stressful situation do not differ significantly between the treatment and control groups.