…it is evident that Ludlow recognized, with remarkable insight, most of the characteristic subjective effects of cannabis. He also noted, and interpreted essentially correctly, such pharmacological points as the relation of dose to effect, inter- and intra-individual variations in response, and the influence of set and setting. Most importantly, perhaps, he recorded the development of his dependence on cannabis more comprehensively and astutely than anyone to date. The initial motives — including features of his own personality and temperament — the constant rationalization, compulsive use despite obvious untoward effects, the progression to a state of almost continuous intoxication, the inability to reduce his dose gradually, and the intense craving and depression after abrupt withdrawal, all are clearly described. Ludlow recognized also the lack of physical symptoms during withdrawal, and the difference from opium withdrawal in this respect.