Introduction Indomethacin, a non-steroidal anti-inflammatory treatment used in various inflammatory diseases, is one of the drugs that has been related to the appearance of psychotic symptoms as a side effect. Objectives Point out the importance of knowing the possible psychiatric symptoms that some drugs can cause as a side effect. Methods Description of a clinical case and bibliography review. Results We present the case of a 71-year-old woman, with no previous mental health history, who is referred by her primary care physician due to the presence of auditory hallucinations and self-referential ideas. As a somatic history, the patient presented Rheumatoid Arthritis under control by rheumatology and acoustic neuroma, under control by neurosurgery. Treatment with Risperidone was started, up to 2 mg, which helped control her symptoms. After an exhaustive study of her situation, the possibility that her symptoms were a side effect of her usual treatment was raised. It was evidenced that the patient had taken a higher dose of Indomethacin than prescribed by the rheumatologist, reason why its daily intake was suspended, and subsequently an improvement and even suppression of symptoms was seen. Later, due to a misunderstanding, the drug was reintroduced, and symptoms appeared again. Conclusions The appearance of psychotic symptoms has been related to the intake of various drugs, including Indomethacin. It is essential to carry out a differential diagnosis if psychotic symptoms appear in the subject. Disclosure No significant relationships.