Adult Dependent Children

I have 3 adult children that either live with me currently or did for more than half of the year.  The oldest is 24 and on Disability.  He lived with me for 9 months and I covered all bills/necessities until he moved out.  My other children are 19 and both work.  Neither has enrolled in college yet but I do provide more than half of their needs.  (They do contribute to the household, just not in amounts that constitute meeting their own needs fully.)  They will file their own taxes. Can any of them be claimed as dependents?