Delirium induced by unknown or não especificado psychoactive substance is characterised by an acute state of disturbed attention and awareness com specific features of Delirium that develops during or soon after substance intoxicação or abstinência or during the uso of an unknown or não especificado substance. The symptoms are not better explained by a primary mental transtorno, by uso of or abstinência from another substance, or by another health condition that is not classified under Mental, behavioural and Transtornos do neurodesenvolvimento.