Abuse has changed the company it keeps before now. On its own, the word has a long history, probably deriving from the Latin verb abuti (to use up or misuse), which itself is formed from ab (away) and uti, usus (use). It established its modern range of meanings fairly quickly, so that before 1600 it was possible to be abused, in the sense of being mistaken; to abuse others, in the sense of verbally denigrating them; and to abuse a tool, in the sense of damaging it. By 1697 a penal law stated that 'none selling wines in gross shall abuse or mix any of them with other ingredients'.
Child abuse may be changing things, but until recently the sense of offensive remarks was probably pre-eminent. Signs reading 'Do not abuse the playground equipment' suggest a world of nervous see-saws, and drug abuse can still have an odd ring to it, as if someone was to sit down and lambast (2) a bottle of aspirin. The first reference the Oxford English Dictionary offers for drug abuse is 1961, and essential to the construction is the idea that a useful tool has turned dangerous through misapplication. You have to think only of how Glasgow addicts inject themselves with solutions of a legitimate drug, such as the sleeping pill Temazepam, to see how concise and accurate the phrase drug abuse is. Remove the safe purpose and it becomes absurd - crack abuse would make sense only if you proposed to use it as cat litter.
How child abuse comes into being is less clear. It seems obvious that the verb form has been drafted to make a compound noun, but the existence of drug abuse and alcohol abuse as a model must have smoothed the way; perhaps the similarities between the expressions betray an unconscious notion that children are there for the disposal of adults, to be used well or badly. We are, I think, less likely to use the compound wife abuse because the notion of a wife as a passive object, a chattel to be husbanded, has all but evaporated, whereas the boundaries of parents' dominion over their children are still being explored.
The first citation for child abuse in the OED is from 1972, but from 1940 onwards a large number of compound words formed with child (child-care, child-benefit, child-guidance, etc) all testify to the growing professionalisation of family life; in this respect we can see child abuse as a growth area of academic (3) specialisation. In 1756 Edmund Burke wrote that 'it is the characteristic of the English drunkard to abuse his wife and family', drawing no distinction between the fate of adult and child. These days a writer would hesitate to use a word as judgemental as 'drunkard' and every member of the family would probably get its own caseworker.
Child abuse is also a euphemism (4), of course, though one that reminds us how useful euphemism can be. To name a social problem is to detach it from the awful realities of individual cases. It is an understandable mistake to believe that the increased frequency of a word or phrase must match the increased frequency of what it refers to, but it is a mistake none the less. Sometimes words come into existence not because they refer to something new, but because we have finally decided we need some way to speak out.
(1) Benign: from the Latin benignus (kind), formed from bene (well) and genus (born, of kind)
(2) Lambast: compound of lam, to lame, from the Old Norse lemja (to lame, to beat) and baste, to beat, from the Swedish basa (to whip, to beat). See also Icelandic beysta (to thrash, to flog). It is a nice, but probably meaningless, coincidence that baste and batter also have culinary meanings.
(3) Academic: from Academus, owner of a garden near Athens in which Plato taught. Cf Horace's silvas Academi, the groves of Academus.
(4) Euphemism: from the Greek euphemizein (to speak fair).