Seasonal Affective Disorder and response to light in two patients with learning disability

Seasonal Affective Disorder is now a well recognised variant of recurrent depressive disorder. No previous description of its occurrence in people with a learning disability has appeared.

Two patients are described who manifested seasonal cycles in mood related behaviour.

Both patients were treated with bright artificial light and showed adequate clinical responses.

Patients with a learning disability and recurrent behavioural changes indicative of a mood disorder should be assessed for the seasonal pattern of the illness and, if appropriate, given a trial of treatment with bright artificial light.

The data relates to two case reports without structured assessments. Further studies in this population should use standardised diagnostic criteria and systematic severity of depression scores.

Patients with poor verbal skills may not be able to express their seasonal changes adequately but careful observation of the timing of behavioural abnormalities may aid the diagnosis of SAD leading to new therapeutic possibilities in phototherapy.