Amongst the psychopathological effects induced by stimulants and cocaine there can be a variety of psychotic-like experiences. Some of them can be resolved in a matter of hours or a few days without clinical tratment, others instead can constitute initial symptoms of a primary psychosis. The objective of this paper is to focalise on a series of psychodynamic aspects, detectable by the analysis of relational dynamics brought into play by the person who has used the substances and has a psychotic crisis. These aspects can be used as criteria of a differential diagnosis, to integrate a first assessment of those psychopathological characteristics described in literature, which distinguish a toxic psychosis from a primary psychosis. The diagnostic process is developed by a method of clinical observation and evaluation, for which the essential cognitive tool is formed by the sensibility of the therapist and their capacity to evaluate the quality of the patient's mental reactions to the stimulus provoked by the development of the therapeutic relationship, which includes oneiric activity. This paper proposes, on the basis of many years of research and clinical experience, diagnostic criteria also in dream analisysis as oneiric images are able to reveal hidden thoughts and dynamics which can be pathological, like negations or annullaments, or non pathological intuitions. This analysis can detecte eventual psychopathological nucleus of psychosis hidden by a state of intoxication and consent the implementation of adequate clinical treatment based on greater diagnostic certainty.