Sleep problems are common in childhood. Disturbed sleep behaviours are among the most common concerns that parents of young children bring to their physicians. Defining disordered sleep behaviour is difficult because of important differences in sleep patterns at different developmental stages. The sudden onset of a sleep disorder or problem can be due to physical, mental and/or environmental factors.

To present the case of a young boy admitted to the emergency department of the Pediatric Hospital of Coimbra due to a sudden inability to sleep.

A 6-year-old boy with previous language delay and undergoing regular psychotherapy due to family distress issues presented with inability to sleep for more than 10–15 minutes. The disturbances started 2 weeks prior to presentation and occurred more than 10 times per night. Immediately after each event the patient was screaming, frightened, unable to communicate normally with his mother. Since the beginning of the episodes the patient's social performance had declined, he was easily irritated, aggressive and with dysphoric mood.

The patient was admitted and evaluated by child psychiatry in the emergency department. An extensive psychiatric evaluation revealed familyrelated stressors, depression and anxiety symptoms. An electroencephalogram was performed which revealed frontal lobe epilepsy.

After the diagnosis treatment sodium valproate was started (30mg/kg/day). The symptoms reversed.

This case highlights how psychiatric manifestations or comorbidity may interfere in the understanding of clinical manifestations of sleep disorders in children. In fact, as in this case, symptoms may be related to underlying conditions, namely epilepsy.