This control group is a waiting list group. Participants received treatment as usual (TAU). Once the RCT is finished, participants have the chance to participate in the intervention group.

Feliz-Mente (third generation psychotherapy):The intervention is delivered in a group format with a total of 12 sessions and a maximum of 10 patients per group. The protocol consists of specific exercises: 1: welcome and identification of emotions, 2: identification and amplification of positive emotions, 3: regulation of negative emotions, 4: gratitude, 5: forgiveness, 6: self-compassion, 7: personal strengths, 8: loving-kindness and positive interpersonal relationships, 9: values, 10: purpose of life, 11: resilience, 12: keeping the change and farewell party.

The intervention aims to improve well-being, without denying the existence of symptoms or problems, focusing on generating positive emotions and actions congruent with the person's values through 11 weekly 90-minute group sessions. The multi-component intervention manual was composed of evidence-based exercises of Positive Psychoterapy Interventions, Acceptance and Commitment Therapy and Mindfulness and was theory driven according the broaden-and-build-theory (Fredrickson, 2001) and the self-serving model of paranoia (Murphy et al., 2018). It was also informed by previous pilot studies carried out on people with paranoid tendencies (see Valiente et al., 2020) and with Severe Psyquiatric Condition samples.

Psychological Well-Being Scales (Ryff, 1995)

Satisfaction with life Scale ( Diener et al. 1985)

Rosenberg self-esteem scale (Rosenberg, 1965)

Relationship Questionnaire (Bartholomew and Horowitz, 1991)