Cultural effects
According to research on hallucinations, both with participants from the general population and people diagnosed with schizophrenia, psychosis and related mental illnesses, there is a relationship between culture and hallucinations. In relation to hallucinations, the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) states that "transient hallucinatory experiences may occur without a mental disorder"; put differently, short or temporary hallucinations are not exclusive to being diagnosed with a mental disorder.In a study of 1,080 people with a schizophrenia diagnosis from seven countries of origin: Austria, Poland, Lithuania, Georgia, Pakistan, Nigeria and Ghana, researchers found that 74.8% of the total participants (n = 1,080) disclosed having experienced more auditory hallucinations in the last year than any other hallucinations from the date of the interview. Further, the study found the highest rates of both auditory hallucinations and visual hallucinations in both of the West African countries, Ghana and Nigeria. In the Ghana sample, n = 76, auditory hallucinations were reported by 90.8% and visual hallucinations were reported by 53.9% of participants. In the Nigeria sample, n = 324, auditory hallucinations were reported by 85.4%, and visual hallucinations were reported by 50.8% of participants. These findings are in line with other studies that have found that visual hallucinations were reported more in traditional cultures.
Certain genetic variations within the TPMT gene can lead to decreased or absent TPMT enzyme activity, and individuals who are homozygous or heterozygous for these types of genetic variations may have increased levels of TGN metabolites and an increased risk of severe bone marrow suppression (myelosuppression) when receiving mercaptopurine. In many ethnicities, TPMT polymorphisms that result in decreased or absent TPMT activity occur with a frequency of approximately 5%, meaning that about 0.25% of people are homozygous for these variants. However, an assay of TPMT activity in red blood cells or a TPMT genetic test can identify people with reduced TPMT activity, allowing for the adjustment of mercaptopurine dose or avoidance of the drug entirely. The FDA-approved drug label for mercaptopurine recommends testing for TPMT activity to identify people at risk for myelotoxicity. Testing for TPMT activity is an example of pharmacogenetics being translated into routine clinical care. History
6-MP was discovered by Nobel Prize winning scientists Gertrude B. Elion and George H. Hitchings at Burroughs Wellcome in Tuckahoe, New York, and was clinically developed in collaboration with investigators at Memorial Hospital (now Memorial Sloan Kettering Cancer Center in New York City). The collaboration was initiated by Cornelius P. Rhoads who had run chemical weapons programs for the US army and had been involved in the work that led to the discovery that nitrogen mustards could potentially be used as cancer drugs, and had become the director of Memorial in 1948. See also
Azathioprine
Tioguanine

References
Further reading
Dean L (2012). "Mercaptopurine Therapy and TPMT Genotype".