Mania 113A possible hint in that direction is that prepubertal children do not have a
euphoric response when given amphetamines or related stimulants.
Causation
Bipolar disorder runs in families – mainly as a result of shared genes
rather than shared environments. The heritability of bipolar disorder is
around 60%. Both population and molecular genetics indicate that there is
a substantial genetic overlap between bipolar disorder and schizophrenia.
Whereas the average IQ is below average in schizophrenia, it is average
in bipolar disorder. Indeed, there is a link with above-average school
performance. A longitudinal study of almost a million Swedish 15–16-
year-olds showed that excellent school grades predicted a fourfold increase
in the risk of later bipolar disorder. Perhaps this reflects the potential
advantages of mild mania-like symptoms such as greater energy and
creativity – advantages that could explain why genes for mania persist in
the population despite the devastating effects of severe bipolar disorder.
Treatment
Acute mania usually needs urgent pharmacotherapy. On the basis of the
relatively limited number of relevant trials involving adolescents, plus
extrapolation from the more extensive adult literature, the treatment
of choice in the acute phase is usually an atypical neuroleptic such as
quetiapine, olanzepine, and risperidone; lithium is second choice; and an
antiepileptic drug such as carbamazepine or valproate is third choice.
In the longer term, lithium – or antiepileptic drugs such as carba-
mazepine, valproate or lamotrigine – can be used to reduce the risk of
recurrence (see Chapter 38).
Bipolar disorder diagnosed with juvenile-specific
criteria
While children and younger adolescents rarely experience classically de-
fined manic or hypomanic episodes, it is fairly common for them to
experience:
1 Short-lived episodes of elevated mood. These episodes mostly last minutes or
hours – far less than the minimum of 4 or 7 days needed to meet ICD-10
and DSM-IV criteria for hypomania and mania respectively. Various ex-
perts have adjusted the duration requirement to classify these episodes
as manic. This is achieved in a variety of ways, including: setting lower
thresholds; letting the duration of brief episodes accumulate until the
total meets the classical threshold; or counting x days with multiple