Perhaps some of the most interesting cases of medical conditions disguised as psychological problems are Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococci (PANDAS), and anti-NMDA encephalitis due to a teratoma.

See it here: https://www.psychologytoday.com/ca/blog/and-running/202105/tips-accurate-mental-health-diagnosis-four-unusual-clues-consider?fbclid=IwAR2v-QFRhasBg950LbgVN41N-G0A97lLtXqqzCNtELP-SlH6OgPNsjHJwmA