Northern Thai people predominate throughout the study district.

Hmong, the second largest ‘hill tribe’ minority ethnic group in Thailand, traditionally cultivated highland rice and maize. Non-narcotic crops now replace their traditional opium cash crop. The study Hmong community relocated from highlands in far western central Chiang Mai Province about 30 years ago, to a lowland and foothill area with an agricultural development project and a paved road to the district town and markets. 

Lahu are the third largest highland minority ethno-linguistic group in Thailand. Lahu respondents in this study mostly speak the Nyi dialect. They traditionally were highland subsistence farmers but are now cash-croppers. 

The Thai Government resettled remnants of the Kuomintang (Nationalist) army from Burma and south-western China along the Thai-Burma border as a buffer against the Communist Chinese government after 1948 (Mote 1967). Yunnanese Chinese study communities split from older communities in about 1966. Recent immigrants come from highland villages in Myanmar and directly from Yunnan, China, primarily for economic opportunities, continuing to arrive during 2011–2012 while data were collected.