Although there is increasing recognition that a substantial proportion of patients with bipolar disorder (BD) experience an onset of illness in adolescence, significant controversy remains over the validity of the diagnosis in very young children. In careful studies of adult patients dating from Kraepelin, first mood episodes not uncommonly occurred during adolescence. Some of these early-onset patients experienced subthreshold mood disturbances or predisposing temperaments earlier in childhood. Earlier onsets of BD have been reported in more recent clinical and community samples of children. Several factors possibly contributed to these earlier onsets, including exposure to psychotropics, bias in favour of a mood rather than a psychotic diagnosis, and recognition of softer-spectrum BDs. However, the validity of the diagnosis of BD in impulsive, irritable, labile, or behaviourally dysregulated children remains to be proven. Studies of high-risk children of well-characterized parents with BD have demonstrated that BD most often debuts as a depressive episode in mid to late adolescence and that activated episodes are rare prior to age 12 years. Some children manifest antecedent nonspecific psychopathology in early childhood. Therefore, as currently diagnosed, BD does not manifest as such typically until at least adolescence.
Talking everyday science to very young children: a study involving parents and practitioners within an early childhood centre