Loneliness, a lack, and solitude, a self-sufficiency, are distinguished. Winnicott's concept of the capacity-to-be-alone is described as the basis of solitude. A child who is watched over non-intrusively by a good-enough mother acquires the foundations of solitude in later life. Where the capacity to be alone has not developed adolescent breakdown may occur. The lonely adolescent encounters bodily phantasies which he may be unable to tolerate. Loneliness is then avoided by clinging or isolation. In psychotherapy the importance of these adolescent experiences is often neglected. Part of the therapist's task is to create a setting in which the patient feels ‘held’ enough to be able to tolerate loneliness and so, eventually, to enjoy solitude.