Psychopharmacologia. 1975 Jun; 42(3): 211-8.

Dose effects of smoked marihuana on human cognitive and motor functions.

Borg J, Gershon S, Alpert M.

Graded doses of marihuana were administered to five adults in a longitudinal repeated-measurements design. Speed of response was the basic parameter measured accross tests of increasing cognitive involvement. Marihuana produced significant dose-response effects of impaired performance in all test scores. However, single automatic motor abilities demonstrated greater sensitivity than tests of greater complexity. Evidence is presented for tolerance development.