Bipolar illnesses are typically considered as disorders primarily occurring in adult life, but a substantial number have their onset during the teenage years. Any acute illness in the teenage years affects social, emotional and educational development disproportionately, as it may prevent the normal transitions and learning experiences inherent in adolescence. Additionally, there is some evidence for a lack of early recognition or for misdiagnosis in early-onset cases of psychiatric disorders in general and the psychotic disorders in particular, with consequent increased suffering and impairment of functioning. Finally, bipolar affective disorders rarely present with one single episode followed by full and permanent recovery, but are usually illnesses characterised by a relapsing and remitting course through adult life. Prompt and effective recognition and treatment may therefore not merely reduce immediate impact but may also set up patterns of understanding and treatment compliance with longer-term implications. In this paper, I consider the particular features of bipolar affective disorder in adolescence and to describe a practical framework for its management. In view of the relative lack of age-specific research findings, particularly in respect of treatment effectiveness, I draw heavily upon clinical practice and extrapolation from studies carried out among adult sufferers.