This paper intends to examine, both from a psychopathological and a phenomenological perspective, the state of “being-at-theworld”, which is common in individuals with drug addiction. Past abuse, as well as present abuse, are crucial in the modification of the psychiatric impact in the history of drug abuse. The former drug lifestyle characterised by the use of heroin led to a form of psychosis which is known with the symptomatological expression as basic psychosis. On the other hand, the contemporary poly-abuse of novel psychoactive substances leads to what is called a synthetic psychosis: a very rich paraphrenic state with continuous hallucinations caused by a mental automatism syndrome and secondary (interpretative) delusions. From a phenomenological point of view, all addictions lead to the final collapse of the Dasein structure (the constitution of the being-in-the-world-with-others). Subsequent to having travelled down many different psychopathological pathways, many addicts remain without the spatial-temporal “here and now” dimension. This makes it impossible for them to stay in a space-with-others and to project themselves in time. The result of this time/space cleavage is emptiness. It is very difficult to treat this existential situation, which is characterised by patients frequently dropping out of conventional treatment, the loss of the being-in-the-world structure, boredom, emptiness, dread, anger, lack of meaning, loneliness and isolation. In this paper, Dasein Group-Analysis (an original interpretation and application of Binswanger’s Dasein-Analysis) is proposed and discussed. Unlike Dasein-Analysis, this approach applies phenomenology beyond the classic pair of analyst and patient, to a group of people composed of doctors and patients, in which everyone is simply a human being in the world. If the psychopathological and therapeutic approaches prove to be ineffective, the frequent consequences are: the patient’s admission into a psychiatric hospital; his/her arrest for crimes related to antisocial behaviour; a worsening of their psychopathology and addiction; a diffusion of infective diseases commonly found in addicts; more frequent overdoses; aggressive behaviour; legal problems; an increase in the costs of public health system; and, finally, even suicide of the patient.