It takes many months for the body to achieve optimal recovery from long-term substance abuse; some brain alteration “appears to be permanent,” according to Kleber, and some has a life of at least a year or two. Positron-emission tomography (PET) scans show the effects of various substances of abuse on the brain, and they show limited recovery even at the three-month point. There are persisting lesions, and chronic abusers of substances often suffer permanent memory damage.
