Non-motor symptoms such as depression, sleep disturbances or hallucinations are common in Parkinson’s disease (PD), but often these are under-recognised and poorly treated. The frequency of non-motor symptoms usually increases with severity of disease and thus are more likely to affect older patients, many of whom may have had PD for 15 years or more. In this article, Drs Doug MacMahon and Simon McIntosh discuss the major non-motor symptoms