Current status of mood stabilizers in the management of bipolar II disorder

There is no consensus definition of the term ‘mood stabiliser’ nor is there universal agreement about what agents count as mood stabilisers in the treatment of bipolar disorder (BP) (Bauer and Mitchner, 2004; Malhi et al., 2005). A stringent definition would include only medications that stabilise mood both from ‘above’ (during mania or hypomania) and from ‘below’ (during depression), while also preventing relapses of hypomania and depression without destabilising the course of the disorder. A more inclusive definition would include any medication that treats or prevents either hypomania or depression without destabilising the course of the disorder. Although several atypical antipsychotics meet this broader definition for a mood stabiliser – and at least one the narrower definition – in this chapter we restrict the term to refer to lithium and anticonvulsant medications that have been assessed for efficacy in the treatment of BP, as atypical antipsychotics are reviewed in other chapters. Anticonvulsants that have some data supporting their therapeutic role in bipolar II (BP II) include valproate (for simplicity, we use valproate to refer to any of its preparations – valproic acid, divalproex sodium, etc.), lamotrigine, carbamazepine, and, much less so, topiramate and gabapentin.