Vol. 7, Issue 1, Part A (2025)

Mycophenolate mofetil (MMF) is a commonly used immunosuppressant that inhibits inosine monophosphate dehydrogenase (IMPDH), a key enzyme in de novo purine biosynthesis. To date, no prior cases have documented the onset and progressive worsening of psychosis linked to long-term MMF monotherapy in pediatric patients. We present the case of a 13-year-old boy with steroid-sensitive nephrotic syndrome who developed progressive psychotic symptoms following long-term MMF use. Despite drug discontinuation, his psychotic symptoms persisted and worsened, resulting in multiple psychiatric hospitalizations. It raises concern for a potentially irreversible neurodevelopmental impact of MMF mediated by sustained purinergic pathway dysfunction during critical neurodevelopmental windows. This case highlights the importance of clinical vigilance regarding the psychiatric risk profile of MMF, particularly in pediatric populations. Although such adverse effects are rare, early recognition and prompt discontinuation may mitigate the risk of long-term neuropsychiatric consequences. Our findings also underscore the need for further research into MMF’s neurodevelopmental effects, routine monitoring for emerging psychiatric symptoms, and exploration of purinergic signalling as a potential mechanistic and therapeutic target in neuropsychiatric illness.