Diroximel Fumarate for Schizophrenia

Inclusion Criteria: * 18 -65 years, diagnosis of schizophrenia (Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) * Stable antipsychotic dose (no change for 1 month) * Currently stable with no evidence of relapse within the last 2 months prior to study enrolment * Minimum of 60 on the Positive and Negative Syndrome Scale (PANSS) * Capacity to provide informed consent Exclusion Criteria: * History of significant co-morbid medical or neurological disorder including but not limited to HIV, malignancies, Systemic Lupus Erythematosus, sarcoidosis, autoimmune vasculitis, bone marrow transplantation * Current use of medication that is known to interact with DRF, live vaccines given within the period of DRF treatment, nephrotoxic medication (including but not limited to aminoglycosides, diuretics, non-steroidal anti-inflammatory drugs, Lithium) * Contraindications to DRF (pregnancy, women of childbearing potential not currently using effective contraception (combined pill (oestrogen \& progesterone), progesterone -only with inhibition of ovulation, intrauterine device, intrauterine hormone-releasing system, bilateral tubal occlusion, vasectomised partner, sexual abstinence), breast feeding, severe hepatic impairment, moderate renal impairment, severe active gastrointestinal disease, lymphocyte count - below the Lower Limit of Normal (LLN) for the local laboratory (e.g 1.30 x109/L LLN for Viapath King's College London), suspected or confirmed progressive multifocal leukoencephalopathy (PML), presence of risk factors for PML (previous and/or current immunosuppressant or immunomodulatory treatment (including natalizumab, other fumaric esters including Dimethyl Fumarate (DMF) (topical or systemic)), serious infection, current or recent herpes virus infection) * Substance dependence/abuse other than to cigarettes * Current high suicide risk * Participation in a clinical study of unlicensed medicines within the previous 30 days * Presence/history of other acute or chronic illness that would make participating unsafe or unsuitable, any contraindication to MRI scanning (e.g. claustrophobia, metallic implants, pacemaker, vascular clips, metal in eyes, pregnancy) * Allergies to any of DRFs ingredients * Taking part in a research study involving an unlicensed medicine within the last 30 days