Meditation dosage predicts self- and teacher-perceived responsiveness to an 18-month randomised controlled trial.

Understanding the factors that predict why some individuals perceive to respond more to meditation training than others could impact the development, efficacy, adherence levels, and implementation of meditation-based interventions. We investigated individual-level variables associated with self- and teacher-perceived responsiveness to longer-term meditation training. This study presents a secondary analysis of the Age-Well trial (NCT02977819, 30/11/2016) and includes 90 healthy older adults (65-84 years) that were randomised to an 18-month meditation training or a non-native language (English) training. Responsiveness was measured post-intervention using participants' and teachers' ratings of four psychological domains (connection, positive/negative emotions, meta-awareness) in relation to two contexts (during sessions, in daily life), teachers' perception of overall benefit, and a global composite comprising all self- and teacher-perceived responsiveness measures. Linear regression modelling indicates that, when including baseline variables (sex, education, neuroticism, cognition, expectancy) and engagement (hours of formal practice during intervention), only higher levels of engagement were associated with higher global composite scores (standardised estimate = 0.50, 95% CI: 0.24-0.77, p < 0.001). Global composite scores were not correlated with pre-post changes in well-being. Findings indicate that more time spent practising meditation was related to greater perceived intervention effects. We suggest that future studies closely monitor levels of engagement and map reasons for disengagement.