intermittent agitation

my 20 yr old brother has been having eriods of agitation, confusion and odd behaviour.

these episodes are allways triggered by a 24-48 hr period of insomnia.

he has had 3 episodes in the last month and although seen by several psychiatrists, we havent been given any answers.
there is a possiblity that he might have taken a stimulant/amphetamines prior to the 1st episode.
any thoughts?
thank you