Bipolar disorder is a psychiatric condition that is both serious and costly. Indeed, bipolar disorder accounts for approximately $US7.6 million annually in direct healthcare costs in the US. Atypical antipsychotic drugs are increasingly being used to treat this disorder, instead of older, less costly conventional antipsychotics. Despite the higher acquisition costs associated with atypical antipsychotics, evidence suggests that their use may in fact lower overall healthcare costs, due to their favourable safety and efficacy profiles, compared with conventional antipsychotics. At the 7th Annual Meeting of the International Society for Pharmacoeconomics and Outcomes Research [Arlington, Virginia, US; May 2002], three studies addressed the use of atypical antipsychotics in bipolar disorder, and the resulting impact on healthcare costs, resource use and hospitalisation.