Comparative efficacy and tolerability of drug treatments for bipolar disorder

Lithium has been the backbone of treatment for bipolar disorder for several decades, although recent advances have identified a number of other medications that have efficacy in treating various phases of the illness. These include the antiepileptic drugs valproate semisodium (divalproex sodium) and carbamazepine and some new antiepileptic drugs (e.g. lamotrigine and topiramate), and the atypical antipsychotics (e.g. olanzapine, clozapine and risperidone). Conventional antipsychotics continue to be used frequently in bipolar disorder, although they may be somewhat less effective than other treatments. Otherwise, to date, none of these treatments have been shown to be consistently more effective than any other, so that drug adverse effects and tolerability often dictate which agents are used in an individual patient. Drugs commonly used for the treatment of bipolar disorder are generally tolerated by most patients in large samples. However, the unique adverse effect signature of a drug will often suggest that it will be less tolerable in some patients than in others. Identifying a specific treatment for a specific patient requires a careful individualised assessment of the risk of adverse effects for that patient's unique circumstances.