Normobaric Oxygen Therapy for Individuals With First-Episode Psychosis

This study is testing whether breathing high levels of oxygen in a normal-pressure environment (normobaric oxygen therapy) can improve symptoms in people who have recently experienced their first episode of psychosis. The idea is that oxygen therapy may support brain healing and improve thinking and mood in the early stages of psychotic illness. **You may be eligible if:** - You are 15 to 35 years old - You have been diagnosed with a schizophrenia-spectrum disorder or a mood disorder with psychotic features - Your first psychotic episode began less than 5 years ago - You estimate average intelligence or above (IQ estimated above 70) - You are a non-smoker and have not smoked for the past 6 months - You have no thoughts of suicide or self-harm in the past month **You may NOT be eligible if:** - You have a history of intellectual disability - You have been smoking recently (within the last 6 months) - You have active suicidal thoughts or behavior - You have medical conditions that may be worsened by supplemental oxygen therapy Talk to your doctor to see if this trial is right for you.