Mental illnesses such as depression, bipolar disorder and schizophrenia affect around 16% of New Zealanders and are difficult to diagnose and treat effectively. Continued research is required to better understand these disorders and develop new medicines. Individuals with small alterations in their DNA, called polymorphisms, can produce different versions of the same protein which might work differently. A few specific versions of Cannabinoid Receptor 2 (CB2), one of the proteins that mediates the effects of cannabis, are more common in patients suffering from mental illness than in the general population. These may play a role in disease cause or progression. In this research we plan to investigate what is different about the function of these versions of CB2 at a cellular level. This will include studying cells donated by patients with schizophrenia. This information will provide insight into the causes of mental illness and may assist with designing new therapies.