Is drug dependence more likely to establish itself in persons whose personality structure is already characterized by a psychological dependence which can be looked at from two aspects: cognitive field dependence and emotional dependence? Three groups of 21 subjects each, multiple drug users, users of cannabis and non-users, are studied with the expectation that the first group is more psychologically dependent than the second one, the latter being in turn more dependent than the group of non-users. The situation is not so simple. Hard-drug users appear to be more active than users of cannabis, whereas non-users are even more dynamic individuals. However, in such a study the duration of consumption exercise an important influence because, in this regard, different personality profiles of the two drug-using groups come into play, the users of cannabis presenting a more incoherent picture. The multiple drug addict selected from his natural environment seems to acquire, through his prolonged consumption, a greater perceptual independence and emotional maturity owing to the clandestine nature of his habit, and a more acute and articulate general way of functioning in order to avoid mishaps.