Putting a Hold on the Downward Spiral of Paranoia in the Social World: A Randomized Controlled Trial of Mindfulness-Based Cognitive Therapy in Individuals with a History of Depression

CONTEXT Paranoia embodies altered representation of the social environment, fuelling altered feelings of social acceptance leading to further mistrust. Mindfulness-based cognitive therapy (MBCT) may relieve paranoia and reduce its impact on social acceptance. OBJECTIVE To determine whether MBCT alters momentary feeling of paranoia and social acceptance in daily life. DESIGN Randomized controlled trial of daily-life repeated measures (up to 120 per participant) before and after allocation to MBCT or waiting list control. PARTICIPANTS Volunteer sample of 130 eligible men and women with residual affective dysregulation after at least one episode of major depressive disorder. INTERVENTIONS Eight weeks of MBCT in groups of 10-15 participants in addition to participants' usual treatment. OUTCOME MEASURES Daily-life ratings of paranoia and social acceptance. This manuscript concerns additional analyses of the original trial; hypotheses were developed after data collection (focus initially on depressive symptoms) but before data analysis. RESULTS Sixty-six participants were assigned to the waiting list control group and 64 to the MBCT intervention group, of whom 66 and 61 respectively were included in the per-protocol analyses. Intention-to-treat analyses revealed a significant group by time interaction in the model of momentary paranoia (b = -.18, p<0.001, d = -0.35) and social acceptance (b = .26, p<0.001, d = 0.41). Paranoia levels in the intervention group were significantly reduced (b = -.11, p<0.001) and feelings of social acceptance significantly increased (b = .18, p<0.001), whereas in the Control condition a significant increase in paranoia (b = .07, p = 0.008) and a decrease in social acceptance was apparent (b = -.09, p = 0.013). The detrimental effect of paranoia on social acceptance was significantly reduced in the MBCT, but not the control group (group by time interaction: b = .12, p = 0.022). CONCLUSIONS MBCT confers a substantial benefit on subclinical paranoia and may interrupt the social processes that maintain and foster paranoia in individuals with residual affective dysregulation. TRIAL REGISTRATION Netherlands Trial Register NTR1084.