Since the mid-1990s, the diagnosis of bipolar disorder has increased significantly: two-fold among adults, four-fold among adolescents and 40-fold among children. Mood instability is a hallmark symptom of many psychiatric disorders but does not imply necessarily a diagnosis of bipolar disorder. Misdiagnosis is not just an academic issue: mood stabilizers have significant adverse effects and expose patients to side effects that range from mild to potentially life-threatening.

Discuss the potential overestimation of bipolar diagnosis in the adolescent population through a statistical analysis of a sample from the adolescence's consultation of Centro Hospitalar Lisboa Norte.

Analysis of 106 patients taking into account the initial diagnosis and the diagnostic stability over 6 months. Non-systematic review of the literature.

From this sample, 39.2% of the adolescents have a diagnose of unipolar affective disorder, 0.02% of bipolar disorder and 0.1% of disruptive mood disorder. These diagnoses did not change over the follow-up period.

It is important to try to understand the reasons of this potential discrepancy (influence of pharmaceutical company marketing, of parents’ desire, of doctors’ fear) to reduce controversy and confusion and to adjust treatment.