IntroductionFunctional neurological disorder challenges conventional medical understanding, presenting neurological symptoms without organic explanations. This report delves into the intricate interplay between psychological and physical manifestations, emphasizing the importance of timely diagnosis and intervention and its impact on a patient’s mental health and quality of life.Case presentationA 40-year-old single Iranian man was admitted for the third time owing to exacerbation of mood symptoms, including depression, irritability, aggression, suicidal ideation, and movement and sensory problems. The patient’s symptoms began with psychological stressors and family conflict, leading to muscle weakness and tremors in the left hand. Over a year, muscle weakness escalated, leading to slow movement, motor impairment in the lower limbs, and reliance on a cane for walking. The patient still exhibited symptoms, such as a mask-like face, stooped walking posture, and a relative improvement of symptoms periodically. At first, the patient was suspected of Parkinson’s disease and was placed on levodopa and amantadine. However, the medication was discontinued owing to an unsatisfactory response and the lack of strong evidence in favor of neurological problems on frequent examinations and reviews. Despite multiple hospitalizations, the patient’s symptoms remained unresolved. Finally, after years of investigations, based on specialists’ recommendations, he was admitted to the psychosomatic ward for diagnostic evaluationele, and he was diagnosed with functional neurological disorder (psychogenic parkinsonism). He underwent pharmacotherapy, electroconvulsive therapy, and psychotherapy. He was discharged with partial improvement of symptoms, but showed periods of relapse and remission during the following years.ConclusionThis case study illuminates functional neurological disorder complexities, emphasizing the need for a holistic diagnostic approach. Timely interventions, including psychological support, can alleviate symptoms, reduce healthcare costs, and improve the overall prognosis. The report contributes to evolving functional neurological disorder understanding in psychiatry and neurology. The report underscores early recognition, advocating for comprehensive interventions involving psychiatric support, cognitive-behavioral therapy, and patient psychoeducation.