Focusing on the interface between psychiatry and medicine, psychosomatic medicine has become a subspecialty of psychiatry. A psychosomatic medicine psychiatrist is like a medicalpsychiatric detective, discovering the clues to psychosomatic patients, and improving their psychiatric care. However, underdiagnosis of psychosomatic disorders is not uncommon. This is because psychosomatic symptoms are usually nonspecific and can come in different disguises, leading physicians to overlook them initially. As a psychosomatic medicine psychiatrist, being familiar with the various ways psychosomatic disorders can present is particularly important in clinical practice. Here, we report a patient who developed haematuria that was later considered an underdiagnosed psychosomatic symptom. A 24- year-old man developed significant anxious and depressive symptoms. Meanwhile, he experienced gross and microscopic haematuria. Urinalysis showed cloudy urine with 50/μL occult blood, 116 red cells, and 2 white cells per high-power field, and no proteinuria or casts. Abdominal and pelvic sonography and intravenous urography did not reveal any significant finding. Cystoscopic examination revealed an increased contraction of the muscle wall without stricture or cystitis of the bladder. Cytologic evaluation of the urine showed no malignant cells. After four sessions of psychotherapy, the patient admitted that his worsening anxiety was mainly related to the issue of him being a homophobic gay, and his homophobia clearly accentuated his anxiety. In the following psychotherapy, he was better able to discuss his ideas about gay men. Interestingly, the patient’s haematuria gradually resolved. Because of the relief from his internal discomfort with homosexuality, the psychotropic drugs were gradually discontinued. During the 12 months of follow-up, the patient never had a recurrence of microscopic and macroscopic haematuria. We suggest that the patient’s haematuria resulted from the remarkable anxiety symptoms because the haematuria occurred during his development of severe anxiety symptoms, and it improved as the anxiety symptoms were relieved. We discuss the possible mechanisms and suggest a “brain–bladder axis.” The breakdown of the mucosal protective defences is a potential mechanism linking anxiety to haematuria. Besides, neurons or microglia synthesize prostaglandin in response to physiological or psychological stress, and prostaglandin E2 is one of the factors generated in this scenario. This case provides another clue to idiopathic haematuria and suggests the possibility of underdiagnosis of psychiatric disorders in cases of urologic conditions. We believe a better understanding of the complex interactions between the brain and the genitourinary system can help urologists and psychosomatic psychiatrists to improve treatments for patients with both conditions.