Psychiatric Comorbidities in 1p36 Deletion Syndrome and Their Treatment—A Case Report

1p36 deletion syndrome represents the most common terminal deletion observed in humans. Major clinical findings comprise developmental delay/intellectual disability, poor or absent expressive language, congenital central muscular hypotonia, brain anomalies, brachydactyly/camptodactyly, short feet, and characteristic facial features like straight eyebrows, deep-set eyes, and midface hypoplasia. So far, there is very limited knowledge about comorbid psychiatric disorders and their effective treatment in this special population. To fill this gap, this case report presents an initially four-year-old girl with 1p36.33–1p36.32 deletion, moderate intellectual disability, insomnia, oppositional-defiant disorder and attention deficit/hyperactivity disorder covering a period of time of about 1.5 years comprising initial psychological/psychiatric assessment, subsequent day clinic/outpatient treatment (amongst others including off-label use of melatonin and methylphenidate as well as parent-child interaction therapy) and follow-up assessment. Follow-up results indicated good efficacy of melatonin and methylphenidate medication without any adverse effects. Multidisciplinarity in diagnosis and treatment are mandatory to meet needs of patients with complex genetic disorders like 1p36 deletion syndrome. Off-label use of melatonin (for insomnia) and methylphenidate (for attention deficit/hyperactivity disorder) should be considered in young children with 1p36 deletion syndrome if behavioral interventions are not sufficient.