Is substance abuse by a parent proof positive of child abuse or neglect?

This dilemma is inspired by a recent episode of the wonderful dramatic show “In Plain Sight”: In the show, divorcing parents with two school-aged children each accuse the other of abusing and neglecting their children. The husband, who is a physician, has been shown to have been prescribing excessive quantities of oxycodone, a painkiller, to his wife. He then proceeds to inform a social worker that his wife’s abuse of the drug constitutes neglect of the children. Apart from the hypocricy of the physician’s attempt to hold his own abuse of his prescription practices against his wife, does the wife’s possible misuse of the drug alone constitute reasonable suspicion that the children are being abused or neglected by the mother? If we take seriously the right of privacy associated with parenthood (see the website’s discussion on constitutional law), then the misuse of medicine does not of itself demonstrate child neglect in the absence of any specific evidence that the children have in fact been mistreated. In other words, this does not present — at least not yet — a “duty to warn” or “duty to protect” case by any mental health professional who comes into contact with this family (please see the website’s discussion of the duty to practice reasonably competently). Parents must be allowed to screw up — to misuse medicine, to drink too much, and to do other things that violate society’s mores — without drawing the immediate inference, without any independent proof, that their children are being abused or neglected. Some alcoholics and substance abusers are excellent parents and never allow their misuse of substance to interfere with important parental responsibilities. What do you think?