T40. GLYCERYL TRINITRATE IN FIRST EPISODE PSYCHOSIS UNMEDICATED WITH ANTIPSYCHOTICS: A RANDOMISED CONTROLLED FEASIBILITY STUDY

BACKGROUND: There is a pressing need for new classes of treatment for psychosis. A key therapeutic target for novel compounds is the NMDA receptor, which may be modulated by nitric oxide donors such as sodium nitroprusside (SNP). Recent early phase studies of SNP in patients with psychosis have had mixed results, and the drug has to be administered intravenously. GTN is a well-established cardiovascular medicine that is also a nitric oxide donor, and can be given orally. We explored the safety and effectiveness of GTN in unmedicated patients with a first episode of psychosis. METHODS: A single-centre, randomized, double-blind, placebo-controlled trial was conducted from December 2016 to April 2019 (ClinicalTrials.gov identifier: NCT02906553). Patients with a first episode of psychosis were recruited from the South London and Maudsley NHS Trust, London, UK. Nineteen patients were randomised to receive 3 x sprays of GTN or placebo for 3 consecutive days, and re-assessed on Day 7. Thirteen participants were included in the final analyses. At each assessment point, symptom levels were measured using the Positive and Negative Syndrome Scale (PANSS), and cognitive performance was evaluated using the Jumping to Conclusions (JTC) and the Hopkins Verbal Learning (HVLT) tasks. RESULTS: Compared to placebo, GTN was well tolerated, but it was not associated with significant effects on either psychotic symptoms or cognition. Bayesian statistics indicated with moderate confidence that GTN does not have a therapeutic effect. DISCUSSION: This study indicates that nitric oxide donors are not therapeutically beneficial in psychosis. It also highlights the difficulties in recruiting unmedicated patients with psychosis. Future clinical trials would benefit from frameworks built into clinical services, to signpost patients not responding to medication and those discontinuing medication to clinical trials of alternatives.