• hypnic headache;
  • lithium carbonate

Hypnic headache constitutes one rare type of primary short-lasting headache related to sleep.

The authors describe two cases of hypnic headache that had a very good response to lithium carbonate. Although these two cases do not fulfill the proposed criteria for hypnic headache, as the pain was not bilateral, and, in case 2, it had a longer duration than previously described, we believe that the very good response to lithium carbonate favors this diagnosis.

We believe that it is important to consider a diagnosis of hypnic headache because of the remarkable response to lithium carbonate shown by some patients with this condition.