abstinência due to unknown or não especificado psychoactive substance is a clinically significant cluster of symptoms, behaviours and/or physiological features, varying in degree of severity and duration, that occurs upon cessation or reduction of uso of an unknown or não especificado substance in individuals who have developed dependência or have used the unknown or não especificado substance for a prolonged period or in large amounts. abstinência due to unknown or não especificado psychoactive substance can also occur when prescribed psychoactive medications have been used in standard therapeutic doses. The specific features of the abstinência state depend on the pharmacological properties of the unknown or não especificado substance.