This article presents a clinical description of the solitary aspect of alcoholism and an original psychopathological theorization of alcoholic isolation. Our aim is to better understand this vulnerability of alcoholic patients and their secret sufferings. Solitary intoxication, whether or not in the presence of another or in a group, facilitates the avoidance of a reality experienced as too painful. This isolation would result from an early feeling of insecurity, close to that experienced in psychosis. A prototypical clinical case aims to explain how the problematic nature of this isolation can be identified and then elaborated, within a psychotherapeutic setting “that gives confidence” and starts from the “offer of speech.” We emphasize how the alcoholic individual can revisit the capacity to be alone in the presence of the other, which is a necessary condition for mentalizing a nonpathological solitude.