Discussion
SRED affects both the genders, ages ranging from 18[9] to 75 years[7]. Onset of SRED was two days[8]. to a few months after starting quetiapine. SRED appeared to occur more amongst the patients suffering from mood disorder rather than schizophrenia. Most of the time the cessation was brought about by stopping the antipsychotic. In one case clonazepam[2]. was added and in another promethazine[7] was added. SRED occurred at doses as low as 25 mg of quetiapine[7] and as in CASE 1, 5 mg of olanzapine. It appeared to be dose dependent as reducing the dose in some cases helped in the cessation of the problem. Switching to olanzapine in case 1 did not help but in case 2 switching to aripirazole resolved the SRED. Possibly there are different mechanism at work.
The mechanism for quetiapine induced SRED may be explained by the serotonin hypothesis of parasomnia[5]. Quetiapine causes:
Strengths:
Both patients had good medication adherence and premorbid function.
There were no comorbidities, concomitant medications than what is mentioned, no previous history of parasomnia, head injury or epilepsy.
Limitations:
Serum quetiapine was never assessed.
The frequency and nature of food, timing of the SRED not well documented as this is a retrospective observation.