**11. Conclusion**

Long-term antipsychotic treatment currently represents a usual outcome for patients with schizophrenia and bipolar disorder. Hyperprolactinaemia can be measured in between 33- 69% of patients in antipsychotic studies and many antipsychotics significantly elevate prolactin with no suggestion of any longer term decline in prolactin levels. Hyperprolactinaemia can no longer be regarded in any sense as a benign abnormality and it may have significant potential short- and potential longer term consequences. Whereas the short-term adverse events are more easily detectable, the potential longer term consequences may remain hidden and undetectable until a bone fracture or cancer emerges. Over the last 10 years, patients receiving biologics to treat rheumatoid arthritis have been entered into voluntary, long-term databases that have addressed, albeit in a naturalistic manner, incidence of potentially associated adverse events (cancers, reactivation of TB, serious infections). There is a need to formally determine the longer term harm of untreated hyperprolactinaemia in psychiatry. In addition, future research needs to focus on the riskbenefit for the usage of prolactin-elevating antipsychotics.
