IF ANYBODY still wonders why cold-blooded murders of men, women and children are becoming a daily part of life in the Washington area, or what might be contributing to increases in crime generally and the incidence of AIDS, the one-word answer now comes with new authority and frightening pervasiveness: drugs. The problems have reached epidemic proportions, according to a new Rand Corp. report -- from the poorest inner-city blocks to the tidy subdivisions and rolling hills of suburban Maryland and Virginia. The message, underscored by comprehensive statistics distilled from heretofore uncoordinated data around the region, is that the depth of drug abuse throughout this metropolitan area is unmatched. Edward F. Mitchell, president of Potomac Electric Power Co. and chairman of a private sector task force that commissioned this report, describes the dimensions:

"It is not an inner-city problem. It is truly a regional problem. It is not a problem that is bounded by race, age, profession or income level. It affects every segment of our society and our community." While none of this is likely to startle law enforcement authorities or those involved in drug treatment in the region, the preview/summary just released and the full report to come in April make some important distinctions about the nature of drug abuse here, the responses so far and the options to be considered in the future. Peter Reuter, chief author, notes that the study is not intended to present a "policy prescription," but it does offer the federal and regional governments a detailed description of how treatment, enforcement and prevention efforts must be tailored to specific abuses.

Heroin users, for example, tend to be a more static, older segment of abusers who commit crimes to cover the costs of their unrelenting addictions; and as needle-users, they are major contributors to the spread of AIDS. But the fast-growing groups are those using PCP and crack cocaine. Among the 26 largest metropolitan areas in the country besides New York, the Washington region ranked first in PCP- and heroin-related deaths and third behind Boston and Miami in deaths related to cocaine.

Treatments -- and results -- vary for each drug. And while law enforcement efforts may be temporarily successful in clearing out a neighborhood market, there has been no decline in use. At the same time, relatively little money has been concentrated on prevention, which the study's authors suggest may provide the best hope for success.

The leaders of every government in this region should get together to create continuing prevention programs -- now; they should be impatiently seeking more information on the effects of PCP use so as to be better able to contain and curtail it, and more treatment centers for heroin addicts, including consideration of the controversial methodone maintenance centers. As Mr. Reuter notes, the drug problems may be more localized than national, though they require federal as well as regional attention. He emphasizes that while "no effort is going to cut rates of drug abuse by 50 percent in five years," approaches using enforcement, treatment, peer pressures and other prevention efforts can make a difference.

At least now -- if people everywhere in this region will recognize that drugs are in their neighborhoods and in the culture of their friends -- the degree of concern and commitment may rise to a point where something can be done.