What is causing my daughter to sleep all the time?

Dear Doctor; I am Ladouce, I have a 4-year-old daughter but she sleeps a lot. All the time whether we are on a motorcycle, in a taxi or even on my lap. I am worried, could this be sickness or she is normal and how can I ensure that this situation stops. Dear Ladouce; You have not specified, whether your daughter has had this problem since birth or it has come recently. Apart from hypersomnolence, does she have any other problem like fever, loss of appetite, loss of weight, e.t.c. It is also important to know whether she sleeps at normal time and soundly in night or is the sleep disturbed due to blocked nose, cough, inadequate feeding, e.t.c. medications containing antiallergy substances like chlorphenaramine, chlorpramazine, e.t.c. can cause much drowsiness . Brain disorders can lead to excess sleepiness but there would be other significant clinical features associated. If the child is eating well, is not irritable in other times, has no other significant health related problems, then this is just a habit. Try keeping her busy in a pleasurable way so that she remains awake during day. Make sure that she sleeps at a fixed hour early in the evening and gets up at fixed time. If the problem continues it is good to have her examined for any hormonal or metabolic disorder like hypothyroidism.