Metacognitive training is a cognitive approach to the treatment of positive symptoms in psychosis.

Metacognitive training consists of ten modules referring to common cognitive issues and biases in solving problems in schizophrenia. The topics of MCT include the following: attribution blaming and taking credit (module 1), jumping to conclusions (modules 2 & 7), changing beliefs (module 3), deficits in theory of mind and social cognition (modules 4 and 6), overconfidence in (memory) errors (module 5), mood (module 8), self-esteem (9) and stigma (10).

Each session lasts 45-60 min and follows a protocol defined in the 'Metacognitive Training for Psychosis (MCT)' manual.

The MCT for Schizophrenia programme will be applied to the group (6-12 persons) applied by therapists in each center. The training format (online or in-person) as well as the frequency (1 or 2 times per week) will vary depending on the center.

structured clinical interview that queries the DSM-5 diagnostic criteria

The WHOQOL-BREF is a 26-item instrument consisting of four domains: physical health (7 items), psychological health (6 items), social relationships (3 items), and environmental health (8 items); it also contains QOL and general health items. Each item of the WHOQOL-BREF is scored from 1 to 5 on a response scale, which is stipulated as a five-point ordinal scale.

Traumatic Experience Checklist. The TEC is a self-report measure addressing 29 types of potentially traumatic events. It is a 29-item retrospective self-report scale. It is a reliable and valid self-report instrument that can be used in clinical practice and research. Different scores can be calculated, including a cumulative score, and scores for emotional neglect, emotional abuse, physical abuse, sexual harassment, sexual abuse, and bodily threat from a person. Only 19-item will be used.

The CBQp is a 30-item questionnaire designed to assess cognitive biases. The questionnaire presents situations frequently encountered in everyday life, along with three response choices reflecting what an individual might think in these situations. The subscales are meant to measure: Internationalising, Catastrophizing, Jumping to Conclusions, Dichotomous Thinking, and Emotional Reasoning biases. In addition, the questions were inspired by two themes relating to psychosis: Anomalous Perceptions (AP) and Threatening Event (TE). A 13-item version of the CBQ will be used.

Brief version of the Internalized Stigma of Mental Illness Scale. The original ISMI scale is a 29-item questionnaire designed to measure the subjective experience of stigma. Each item is rated on a four-point Likert scale from 1 (strongly disagree) to 4 (strongly agree). The subscales measure: Alienation, Stereotype Endorsement, Perceived Discrimination, Social Withdrawal, and Stigma Resistance. A 10-item version of the ISMI containing the two strongest items from each subscale.

Short version of the questionnaire of stressful life events. The original QSLE scale is a 52-item questionnaire designed to measure stressful life events. The abbreviated QSLE-SV with 18 items shows the importance of different life dimensions such as education, work, family, legal and health. In the study, we will use 9 items from the abbreviated version of the tool.

The Reflective Functioning Questionnaire. The RFQ is a brief 8-item self-report measure of mentalizing, i.e., the capacity to interpret the self and others in terms of internal mental states such as feelings, wishes, goals, desires, and attitudes. Individuals in the RFQ respond to each item on a seven-point scale between "strongly disagree" and "strongly agree" response options.

Insomnia Severity Index. The ISI is a 7-item self-report questionnaire assessing the nature, severity, and impact of insomnia. The usual recall period is the "last two weeks" and the dimensions evaluated are: severity of sleep onset, sleep maintenance, and early morning awakening problems, sleep dissatisfaction, interference of sleep difficulties with daytime functioning, noticeability of sleep problems by others, and distress caused by the sleep difficulties. A 5-point Likert scale is used to rate each item (e.g., 0 = no problem; 4 = very severe problem), yielding a total score ranging from 0 to 28.

The Scale to Assess Unawareness of Mental Disorder. The SUMD is a 20-item scale that assesses current and past awareness of illness. The first three items, which assess general awareness of mental illness, are (1) awareness of mental disorder, (2) effects of medication, and (3) social consequences of mental disorder. Items 4-20 pertain to specific symptoms. If the subject shows awareness of a symptom, he/she is asked about the attribution of this symptom. Awareness and attribution items are rated from 1 to 5, with higher scores indicating poorer awareness or attribution. The 17 symptom items render four subscale scores: current awareness, past awareness, current attribution, and past attribution. Only 3-item of SUMD will be used.

Brief Form of the Interpersonal Reactivity Index. The IRI is designed to measure empathy as a set of constructs in addition to a unitary concept. The 28-item IRI is a self-report measure consisting of four 7-item subscales: Perspective Taking (tendency to adopt the psychological point of view of others); Fantasy (tendency to transpose oneself imaginatively into the feelings and actions of fictitious characters in books, movies, and plays); Empathic Concern (feelings of sympathy and concern for others); and Personal Distress (feelings "self-oriented" feelings of personal anxiety and unease in tense interpersonal settings). B-IRI is a short version of IRI containing a 16-item scale.

Short Version of the Beck Hopelessness. The original BHS is a 20-item self-report inventory designed to measure three major aspects of hopelessness: feelings about the future, loss of motivation, and expectations. It is a true-false test that measures the extent of the respondent's negative attitudes, or pessimism about the future. It may be used as an indicator of suicidal risk in depressed people who have made suicide attempts. The short version of BHS is a 4-item scale, which includes all the affective, cognitive, and motivational components of hopelessness.

The Patient Health Questionnaire-9. The PHQ-9 is the 9-item depression module from the full PHQ. As a severity measure, the PHQ-9 score can range from 0 to 27, since each of the nine items can be scored from 0 (not at all) to 3 (nearly every day).

The Internal, Personal, and Situational Attributions Questionnaire. The IPSAQ has 32 items describing 16 positive and 16 negative social situations in the second person. For positive and negative events two measures of internality are derived from responses: a measure of self-blame and a measure of the extent to which external attributions implicate others as opposed to situations. Three positive and three negative subscale scores are generated by summing the number of internal attributions, the number of personal attributions and situational attributions chosen for both the positive and negative items. Two cognitive bias scores are derived from these six subscale scores (External and Personalizing bias). We will use 4 items - 2 positive and 2 negative situations

A questionnaire evaluating subjective training success will be handed out to the patients at the end of the training. This subjective appraisal rating was previously used in a study on the MCT (Moritz and Woodward, 2007), which found the internal consistency to be satisfactory (Cronbach's alpha = .73). The measure contained ten items covering distinct aspects of training satisfaction: effectiveness, usefulness, applicability to daily life, transparency of the aims and fun. Each item had to be rated on a 5-point scale (1 = does not agree at all - 5 = totally agree). Higher scores thus designated greater satisfaction.

The Trail-Making Test. The TMT is a neuropsychological test that involves visual scanning and working memory. The TMT has two parts: the TMT-A (rote memory) and TMT-B (executive functioning). In each test, the participant is asked to draw a line between 24 consecutive circles randomly arranged on a page. The TMT-A uses all numbers, whereas the TMT-B alternates numbers and letters, requiring the patient to switch between numbers and letters in consecutive order. The TMT is scored by how long it takes to complete the test. The time includes the correction of errors prompted by the examiner. If the person cannot complete the test in 5 minutes, the test is discontinued.

he Fish Task is a computerized variant of the probabilistic reasoning task designed to capture jumping to conclusion, a prominent bias targeted by two modules of MCT.

Baron Cohen's Face Test. Facial emotion recognition test originally developed in the construction of the Reading the Mind in the Eyes Test. BCFT consists of 20-items showing pictures of an actress displaying an emotion.Participants must choose which emotion the actress is feeling between two different choices of response. Half of the items display basic emotions, whilst the other half displays complex mental states. We will use a 4-item version and additionally participants will be asked for their confidence rated on a 5-point scale.

This task is a measure of the ability to infer the 'real intentions' behind indirect comments. It consists of 10 short passages, each describing a social interaction between two characters, ending with one character 'dropping' a hint to the other. Subjects were required to infer the actual meaning of the hint. If a subject fails to give a correct answer, a more obvious hint is provided. An appropriate response to the first hint is scored with two points. If a correct response is given only after a more obvious hint, a score of one was given. If the subject fails to give a correct answer to either of the two hints, a score of zero was given. A random selection of three stories will be presented to participants.

After every session, participants will receive a brief questionnaire assessing the severity of the present symptoms (cognitive biases - 4 items (based on DACOBS, Davos Assessment of the Cognitive Biases Scale), positive symptoms - 4 items, negative/affective symptoms - 6 items (basen on PRISS, Patient-Reported Impact of Symptoms in Schizophrenia Scale ).