Effects of a mindfulness-based intervention on diurnal cortisol pattern in disadvantaged families : a randomized controlled trial

Abstract

Objective: The present study examined the psychophysiological effects of Family-based Mindfulness Intervention (FBMI) on children and parents from disadvantaged families. Methods: This randomized controlled trial recruited parents and their children from 51 disadvantaged families in Hong Kong and randomized them into FBMI (n = 26) and waitlist control (n = 25) groups. The parent intervention included 6 sessions and the child intervention included 8 sessions with 2 half-hour joint programs. Both interventions lasted 9 hours in total each. All participants completed four salivary cortisol measures after wakeup, before lunchtime, late-afternoon, and before sleep at baseline and end of the intervention. The diurnal cortisol pattern was summarized by the morning cortisol, evening cortisol, mean cortisol, and diurnal cortisol slope. Results: Compared to the control group, children in the FBMI group showed significant increases in morning cortisol (d = 0.50, p = 0.03) and significant decreases in diurnal cortisol slopes (d = 0.50, p = 0.04) at the end of intervention. Parents in the FBMI group displayed significant decreases in evening cortisol (d = 0.50, p = 0.04) compared to the control group at the end of intervention. No significant treatment effects were found on the mean cortisol. Discussion: The present findings suggest that FBMI could improve the diurnal cortisol slope and cortisol levels of the children and parents from disadvantaged families, respectively. Future studies should elucidate its potential benefits on neuroendocrine functioning.