While psychotic symptoms may be the result of a primary psychiatric disorder, they can also be the presenting symptom of an underlying somatic disease. The organic aetiology can vary from benign and transient to severe and enduring disorders. Early diagnosis and treatment can be crucial to the prognosis, though potentially challenging as well, given that several of the organic aetiologies are rare and therefore difficult to identify. This case report describes two pediatric patients with psychiatric manifestations as a result of 22q11.2 deletion syndrome and anti-N-methyl-D-aspartate receptor encephalitis.