A private corporation conducted a study for the United States Air Force in 1973, investigating the long term effects of drug use on general mental ability. The air force personnel selected for participation in the study were 3741 known drug users and 6772 controls. Subjects received requests to sign a form allowing their high schools to release their transcripts and test scores to the Air Force. Signed releases were forwarded to the high schools who in turn sent transcripts and test scores to the Air Force. Scores of the various general ability tests which subjects had taken in high school were converted to a standard form and compared with scores on the Airman Qualifying Examination (AQE). Results indicate little or no significant change in mental ability as a result of drug use. Such differences as did exist cannot be stated to be a function of drug use per se; the fact of drug use seems far more important than any other variable. Peer group influences on drug users and the attitudes of the drug user group toward the Air Force, and possibly toward the AQE, could have differed sufficiently from those of the control group when the subjects took the AQE to cause the slight differences in mental ability observed between the two groups. Extensive (n-46) data tables follow the body of the report. (Author/NM)