Bipolar disorder and dopamine dysfunction: an indirect approach focusing on tardive movement syndromes in a naturalistic setting.

Background: It has been suggested that dopamine dysfunction may play a role in bipolar disorder (BD). An indirect approach to examine this issue was developed, focusing on associations between dopamine proxy measures observed in BD (dopamine-related clinical traits using tardive movement syndromes as dopamine proxy measure of reference).
Methods: 3459 eligible bipolar patients were enrolled in an observational study. Incidence rates of tardive movement syndromes (tardive dyskinesia and tardive dystonia; TDD) were examined. A priori hypothesized associations between incident TDD and other dopamine proxies (e.g. prolactin-related adverse effects, bipolar symptoms) were tested over a 2 year follow-up period.
Results: The incidence rate of tardive syndromes was 4.1 %. Incident TDD was independently associated not only with use of antipsychotics, but also with more severe bipolar symptoms, other extrapyramidal symptoms and prolactin-related adverse effects of medication.
Conclusion: Apart from the well-known association with antipsychotics, development of TDD was associated with various other dopamine proxy measures, indirectly supporting the notion of generalised dopamine dysregulation in BD.