A major search operation has been launched involving officers from Kent Police, a force helicopter and volunteers from the Kent Lowlands search and rescue.
The search was launched in the early hours of Saturday morning.
Teams were called to Maidstone hospital after the man was reported missing to Police.
A national air support helicopter from Redhill has carried out a search of Maidstone hospital, Barming and Mote Park under the cover of darkness using a thermal imaging camera in attempts to locate the high risk missing person.
Trained Lowland volunteers have been searching a nearby wooded area and have been using mountain bikes using the man last known location.
Kent Police have been approached for more details