Clinical High Risk for Psychosis

The goal of this clinical trial is to determine whether a gamified eye-movement intervention can improve cognitive function in individuals across the schizophrenia spectrum, including clinical high-risk individuals, first-episode schizophrenia patients, and chronic schizophrenia patients. The main questions it aims to answer are: * Does eye-movement training improve cognitive performance measured by the MATRICS Consensus Cognitive Battery (MCCB)? * Does eye-movement training improve oculomotor functions and clinical symptoms across different illness stages? Researchers will compare an eye-movement intervention group with an active control group receiving matched finger-controlled game training to determine whether the eye-movement intervention produces greater improvements in cognitive function and eye-movement performance. Participants will: * Receive either gamified eye-movement training or matched finger-controlled game training for 4 weeks. * Complete cognitive assessments using the MCCB before and after the intervention. * Complete standardized eye-tracking tasks, including fixation stability, smooth pursuit, antisaccade, and free-viewing tasks, to evaluate changes in oculomotor control and visual exploration patterns. * Complete clinical symptom assessments using SOPS or PANSS according to illness stage.

The purpose of this trial is: * To investigate whether cannabidiol (CBD), compared to placebo, can reduce the severity of attenuated psychotic symptoms in individuals at clinical high risk for psychosis. * To confirm the safety of CBD in individuals at clinical high risk for psychosis. The trial is a randomised, double-blind, placebo-controlled, multi-centre, international clinical trial. Individuals meeting clinical high risk for psychosis criteria will be recruited for the trial intervention component of the trial. Participants are randomised to treatment with oral CBD 300mg (oral solution 100 mg/mL) twice daily, or a matching placebo, for 104 weeks. By using a battery of clinical outcome assessments, the trial will be able to assess several biomarkers to predict clinical outcomes and response to treatment with CBD. Participants will be invited to provide blood samples, stool samples, cerebrospinal fluid samples (if aged 18 years or over) and complete neuroimaging assessments. Individuals who are not found to have mental illness as defined by DSM-5 criteria will be recruited to a healthy control group, to validate the biomarker component of the trial. Additionally, a control group of healthy volunteers will be recruited who will not take the trial intervention to aid calibration between datasets from sites acquiring MRI data and to inform and validate any possible multivariate signature associated with the CHR-P state, course or outcome by understanding how these measures are different in controls. Healthy controls will also be used for secondary case-control comparisons. Healthy controls will undergo clinical and biomarker assessments only.

This is a dissemination and implementation study that is evaluating a stepped-care intervention for identifying and treating youths at clinical high-risk for psychosis within multiple community mental health centers.