A single center randomized controlled clinical trial with pre and post-treatment measures was designed. Sixty-eight people diagnosed with psychotic disorder from a public community rehabilitation center were assessed for eligibility. Inclusion criteria were (1) age between 18-65; (2) one of the following DSM-IV-TR diagnosis: Schizophrenia (295.30; 295.10; 295.90), Schizoaffective Disorder (295.70), Delusional Disorder (295.70), Bipolar Disorder (296.40; 296.4x; 296.5x; 296.5x); (3) no changes in psychiatric medication or hospitalization in last month; (4) have signed informed consent; and (5) be able to understand and read the Spanish language. Exclusion criteria were (1) significant cognitive impairment assessed through clinical record; (2) inability to attend mindfulness or rehabilitation treatment sessions; (3) posed a risk of violence to the researchers; and (4) refused to participate or to sign informed consent. Due the naturalistic nature of the study, the sample was composed of different DSM-IV-TR diagnoses which had the common feature of presence of psychotic experiences and sensations. Also, participants in the study were unemployed, without any medical condition that could affect treatment outcome, were under anti-psychotic drug treatment, and did not showed comorbidity with other axis I or II DSM-IV-TR disorder. No payment was made for participation in the study. Data collection was carried between August 2013 and July 2015 at the same community rehabilitation center. Intention-to-treat analysis was used.

Multiple stochastic imputation was selected to deal with missing data (Scharfstein & McDermott, 2019). The study complied with the Declaration of Helsinki and was approved by the Research Ethics Committee of the University of Balearic Islands. Informed consent was obtained of each participant. Trial was registered in ISRCTN Registry: ISRCTN52873519.

Individuals were contacted initially by their psychiatrist to perform a personal interview to be informed about mindfulness and what participation in the trial would involve and to assess eligibility. At the end of the interview eligible participants, or their legal guardians, were invited to participate and sign informed consent. After informed consent for trial participation was signed, randomization identification was assigned to each patient and recorded in the clinical record form. A master randomization list was created to record randomization identifications and corresponding treatment assignment, access to master randomization list was restricted to psychologist and psychiatrist who led mindfulness sessions. Patients were assessed by a research psychologist specifically trained to manage patients with psychotic features and coordinate clinical trials who was blind to patient allocation. Once assessed, participants were randomly allocated by software to Integrated Rehabilitation Treatment (IRT) or IRT + MBI group, with a maximum group size for MBI ranging from 8 to 12. Each of the three cohorts was randomized once numbers were sufficient to begin a mindfulness group. Recruitment process is detailed in Figure 1.

Figure 1.

CONSORT flowchart.

(0.16MB).

Demographic data and clinical features of participants were collected through a specifically designed clinical record form. Age, sex, psychotic disorder diagnosed, age at onset and years of education were recorded. Diagnoses were obtained through clinical record. Participants were assessed before and after treatment completion.

Spanish adaptation of the Positive and Negative Syndrome Scale (PANSS; Kay, Fiszbein, Vital-Herne, & Fuentes, 1990) was used to assess the frequency and intensity of psychotic symptoms. Interviews were videotaped to be scored at the end of the intervention by two clinical psychologists who were blinded to patient allocation.

Mindfulness Attention Awareness Scale (MAAS; Brown & Ryan, 2003) was used to detect changes in general mindfulness awareness in daily life. This 15-item scale focuses on attention/awareness component of mindfulness construct, and can be used to assess individuals either with or without meditation experience. The Spanish version of MAAS has good reliability indexes and good temporal stability (Soler et al., 2012).

Assessment of IC was conducted using the non-congruent trial of Stroop Color Word Test (SCWT; Golden, 1978). Paper and pencil version was used as it is validated in the Spanish population. Psychometric properties are equivalent to the original English version, and its considered a better measure of IC than the computerized versions of the Stroop paradigm (Penner et al., 2012). This version of the Stroop paradigm consists of three 45-second trials. In the first trial the participant reads aloud a series of color names printed in black as fast as possible. In the second trial they name the color of a series of ink swatches. In the third, non-congruent, trial, the participant is shown lists of color names printed in ink of a conflicting color and asked to name the ink color rather than reading the color word. Non-congruent trial requires recruitment of processes regarding the operation of deliberately inhibit dominant responses and select less likely behavior in presence of a competing tendency (Diamond, 2013). The non-congruent condition of SCWT is a reliable tool to assess IC in people experiencing psychosis: it is robust to within-subjects variability and detects changes in IC performance even when controlling for education and global cognitive performance (Laurenson et al., 2015; Scarpina & Tagini, 2017). SCWT also combines its reliability with enough sensitive capacity to detect cognitive impairment in psychotic disorders (Shi et al., 2019). Elements processed in 45 seconds were recorded as raw scores and used for statistical analyses.

There were two treatment arms: IRT and IRT enhanced with group MBI. Both arms were delivered by routine clinical staff trained in rehabilitation and treatment of people experiencing psychoses, and for IRT + MBI in mindfulness applied to psychosis. IRT was a 26-week rehabilitation treatment oriented to manage intensity and frequency of psychotic symptoms, prevent relapses and hospitalization, as well improve social functioning. IRT comprised 26 one-hour weekly group sessions of cognitive behavior therapy techniques for symptom management as well as strategies for preventing relapse and conflict management. Bearing in mind the mediation effect of daily life stressors in the relationship between psychotic experiences and psychological well-being (López-Navarro, del Canto, Mayol, Fernández-Alonso, & Munar, 2018), group sessions were designed with a strong component of social skills training. Sessions one to six aimed to teach participants about the A-B-C schema and how feelings and thoughts are related with environment. Sessions seven to nine were designed to illustrate the A-B-C schema with daily life situations reported by the participants. During sessions ten to sixteen participants were taught about social skills and assertiveness techniques, which contents were used for the role-playing sessions seventeen to twenty. Finally, sessions twenty-one to twenty-six entailed problem solving applied to daily-life social situations reported by the participants as distressful or harmful for them. Along the group sessions, to prevent relapse and hospitalization each participant was interviewed once a week to adjust pharmacotherapy treatment – if necessary –. IRT contained no mindfulness training or family intervention.

IRT + MBI group ran throughout the 26-week rehabilitation treatment program. Mindfulness component followed the protocol described by López-Navarro et al. (2015). The first author attended 60% sessions to confirm treatment fidelity against the manual. The aim of the mindfulness sessions was to change how participants relate with the psychotic sensations. Mindfulness teach to react with acceptance to the content of the experience instead struggling with. In sum, mindfulness sessions sought to teach participants to perceive voices or thoughts as what they are and not what they say they are. Mindfulness group therapy sessions lasted 60 minutes and were carried out in venue ceded for free by city council. As physical sensations are used in mindfulness applied to psychoses to anchor to the present moment, every session began with a habituation period to the room with relaxing music as background followed by 10-minute body awareness exercises led by a trained psychologist. Then, 15 minutes of guided meditation was led by a psychiatrist and a clinical psychologist trained in mindfulness and experienced in working with psychotic patients. Frequent guidance was imparted encouraging awareness and acceptance of bodily sensations, sensations of breathing, and thoughts, images and voices that might arise. To achieve this, instructions given sought to foster participants to advert and let go of worry and engagement with the content of thoughts, voices or other psychotic symptoms that might arise, and of criticism or judgement. Finally, sessions included 15 minutes of reflective group discussion aimed at facilitating patients’ understanding and insights drawn from the mindfulness practice. Home practice was encouraged between mindfulness sessions and participants were given an audio tape for home practice with the guidance instructions used during group sessions.

Descriptive statistics were generated for the sample and for each treatment arm. Statistical analyses were performed using raw scores. Assumption of normality and homogeneity of variances was tested in the outcome variable before conduct analyses, using Shapiro-Wilk test and Levene test respectively. Groups were compared at baseline on sociodemographic, clinical variables, self-reported mindfulness, and SCWT scores. The primary outcome variable was IC measured through SCWT non-congruent trial, and self-reported mindfulness assessed with MAAS scale was set as secondary outcome.

To test for group differences, a repeated-measures analysis of variance (ANOVA) was conducted for STCW non-congruent trial and MAAS scores. Treatment condition (IRT, IRT + MBI) was set as between-participants factor and Time (baseline and post-treatment) as within-participants factor. Thus for every measure, there are seven lines of results: the four simple effects, the two main effects -Treatment and Time-, and the interaction effect between these two factors. Interaction was analyzed using Bonferroni correction to control Type I error rate across comparisons. Eta squared was used as effect size. Reliable Change Index (RCI), following the recommendations of Christensen and Mendoza (1986), was used to estimate individual change in primary and secondary outcomes. If parametric assumptions were not met a bootstrapped ANOVA was performed at 2000 iterations. Data were analyzed with IBM SPSS 23 for Windows. Statistical significance was set at .05.