What could be some reason why a child is sleep walking?

Sleep walk.: One theory is that the cause is a delay in maturation of the central nervous system. Other possibilities include genetic predisposition, excess tiredness, sleep deprivation, fever, other sleep disorders such as restless legs, or medications.

Sleepwalking : Sleepwalking can be caused by apoor daytime schedule, stress in the house, medication a full bladder or enuresis as well as illness.

Sleep issues: Sleep walking/talking/terrors are often related to lack of adequate sleep habits.They often arise or worsen during periods of excessive scheduled activities.An 11 yo should never try to get by on less than 9 hrs/night and heavy sport participation or studying adds to that need.Sleeep more/walk less.