Abstract
BACKGROUND: Psychotic disorders are characterized by both positive symptoms (hallucinations, delusions) and negative symptoms (emotional blunting, anhedonia) that impair daily functioning. While antipsychotic drugs and psychological interventions are effective when addressing positive symptoms, treatment of negative symptoms remains an ongoing challenge. Mindfulness-based interventions (MBIs) have been shown to reduce negative psychotic symptoms. However, as negative psychotic symptoms are assessed as a sole entity rather than a sum of manifestations, the effect of MBIs remains unclear. AIM: To examine the effects of MBI in addition to integrated rehabilitation treatment (IRT) for people experiencing psychosis on each of the negative psychotic symptoms. METHODS: A randomized controlled clinical trial with preintervention and postintervention measures was designed. The main outcome variable was negative psychotic symptoms assessed through the seven subscales of the Spanish version of the positive and negative syndrome scale. Data were analyzed using a repeated measures analysis of variance and reliable change index calculation. RESULTS: There were no statistical differences between groups at the preintervention assessment. Statistically significant differences were found after MBI for the time in emotional withdrawal (F = 37.75, P < 0.001, η (2) = 0.437) and social withdrawal (F = 37.75, P < 0.001, η (2) = 0.437). CONCLUSION: MBI added to IRT reduced the lack of interest and involvement with affective commitment to daily life activities, and interest and engagement in social activities increased. These negative psychotic symptoms were not improved by IRT alone.