Maori, marijuana and schizophrenia

An international conference on mental health has had new papers about marijuana presented to it. It is reported in today's Dompost;

Doctors at Yale University in the United States tested the impact of THC on 150 healthy volunteers and 13 people with stable schizophrenia. Nearly half of the healthy subjects experienced psychotic symptoms when given the drug. Though the doctors expected to see marijuana improve the conditions of their schizophrenic subjects - since their patients reported the drug calmed them - they found the reverse was true. The study stopped early because the impact was so pronounced that it would have been unethical to test it on more people with schizophrenia.

Late last year a paper investigating the growth of numbers on the invalids benefit was published. Here is an excerpt;

The rate of growth in inflows was most rapid for Māori and Pacific peoples (41% and 36% respectively, compared with 24% for the New Zealand and other European grouping). It is likely that significant changes in the recording and coding of ethnicity in benefit administration data partly account for this.26 Variations in the rate of population growth or in the rate of population ageing between ethnic groups may also be important.

Most of the growth in the number of Māori and Pacific entrants is explained by incapacities other than the five that generated most of the overall growth.

* For Māori, this reflects larger contributions from schizophrenia (accounting for 12% of the growth in Māori inflows at ages 15–59), cancer (7%), respiratory (6%), circulatory (5%) and nervous (5%) conditions.
* For Pacific peoples, it reflects larger contributions from circulatory conditions (accounting for 23% of the growth in Pacific inflows at ages 15–59), endocrine conditions (17%) and cancer (10%).


Interestingly there was no growth in inflows due to schizophrenia for NZ and other European yet it isn't just Maori using marijuana. There is something else predisposing Maori to schizophrenia. I'm not arguing that dope isn't a factor but there is something else as well.

There is a theory that suggests schizophrenia is caused by a virus which arose hundreds of years ago and swept across Europe. Because Europeans have had centuries of exposure some evolutionary defence has developed. Maori, however, have not had that same length of exposure. It's a possibility they are still more susceptible to schizophrenia for that reason.