The aim of this pilot study is to examine whether metacognitive training can improve symptoms, wellbeing and functioning in individuals with attenuated psychotic symptoms. Metacognitive group training is an intervention designed to raise awareness on and change cognitive biases that may foster the development of psychotic symptoms such as delusions. It has been shown to be helpful in people with manifest psychosis. The main goal is to assess whether this training is prone to reducing symptoms in individuals at risk for psychosis. Participants will be randomized either to treatment as usual or to treatment as usual plus metacognitive training. Follow-ups will be performed over the period of one year.

Background: Different metacognitive distortions similar to those of patients with schizophrenia could be shown in individuals with attenuated psychotic symptoms at ultra-high risk for psychosis (UHR) including more dysfunctional metacognitive beliefs, overconfidence in judgements, a jumping-to- conclusion reasoning style associated with impaired working memory, a metamemory bias and intolerance of uncertainty. Recent research points towards a positive effect of metacognitive training (MCT) on positive symptoms, data gathering and delusions in patients with schizophrenia by raising awareness for cognitive biases.

Aims: The aim of this study is to examine whether metacognitive training can improve psychopathology in individuals with attenuated psychotic symptoms via changes in metacognitive biases and beliefs. Study design: The study is randomized-controlled, prospective.

Methods: 15 individuals fulfilling UHR criteria will be randomly assigned to a group receiving MCT+treatment as usual (TAU) at an early psychosis clinic for a duration of approximately 8-12 weeks and 15 individuals fulfilling UHR criteria will receive TAU only. Both groups will undergo psychiatric assessments to exclude current or past psychiatric disorders as well as psychosis threshold and current psychopathology. Also, an assessment of IQ, psychosocial functioning and metacognitive biases and beliefs will be done. Assessments will be done at baseline, after 12, 26 and 52 weeks.

Study sample: The study sample will consist of 30 individuals at UHR between 16 and 40 years of age.

Main outcome variable: Changes in the positive subscale score as a measure of positive symptoms of the Positive and Negative Syndrome Scale (PANSS) Secondary outcome variables: (i) Changes in SOFAS score; (ii) Changes in metacognitive biases and beliefs; (iii) Changes in PANSS total score Power analysis: The aim of this pilot study is to better understand the magnitude of the treatment effect and its variability, such that future studies can be properly powered. A sample size of 15 in each group was decided upon, with an asymptotic, two-sided 95% confidence interval.

Inclusion Criteria:

(i) Age 16-40 years; (ii) individuals belonging to either one of the following two groups:

• attenuated psychotic symptoms (APS): Experience of subthreshold, attenuated forms of positive psychotic symptoms including ideas of reference, odd beliefs or magical thinking, perceptual disturbance, paranoid ideation, odd thinking and speech, odd behavior and appearance, at least several times per week within the last year, present for at least one week and no longer than five years, according to the criteria operationalized in the Comprehensive Assessment of At Risk Mental State (CAARMS) interview (Yung et al., 2003);
• brief limited intermittent psychotic symptoms (BLIPS): Episodes of frank psychotic symptoms that have not lasted longer than a week and have spontaneously abated, according to the criteria operationalized in the CAARMS interview (Yung et al., 2003); (iii) ability to give informed consent and to follow study procedures

Exclusion Criteria:

(i) Past history of a treated or untreated manifest psychotic episode of one week's duration or longer (ii) Increases of dosages of antipsychotic medications - if any is given at all - within the last two weeks and/or clinical necessity for dosage increases at time of inclusion; (iii) Past neuroleptic exposure exceeding a total lifetime haloperidol dose of 50 mg (equivalent doses as referred to in Gardner, Murphy, O'Donnell, Centorrino, and Baldessarini (2010)); (iv) Acute suicidality or acute aggressive behavior; (v) Current attenuated symptoms that are entirely explained by acute intoxication (e.g., current attenuated symptoms entirely explained by LSD use) (vi) Organic brain disease (e.g. epilepsy, inflammatory brain disease etc.); (vii) Any other physical illness with psychotropic effect, if not stabilized; (viii) Diagnosis of a serious developmental disorder, e.g. Asperger ́s syndrome; (ix) Premorbid IQ lower than 70; (x) Inadequate knowledge of German language