insomniac

insomniac (http://definr.com/insomniac)

     adj : experiencing or accompanied by sleeplessness; "insomniac old
           people"; "insomniac nights"; "lay sleepless all night";
           "twenty watchful, weary, tedious nights"- Shakespeare
           [syn: sleepless, watchful]
     n : someone who cannot sleep [syn: sleepless person]