Hi, thanks so much for this information, probably the most useful and reliable source about the use of D. Spinosa I've found to date.

I live in a pretty wild area in Patagonia, Argentina, and I'm basically surrounded by D. Spinosa, among other endemic species. I think I probably have hundreds of wild specimens in my little piece of land.

I knew for some years of its use thanks to the Internet, and also through the local native people, the Mapuche, who are pretty secretive about, but they always admitted the use.

A very interesting fact is that they also mention that it's similar to Cannabis, and they also say they traditionally smoke it mixed with another native species, which I couldn't find yet which one is it.
I suspect it could be Berberis darwinii or Berberis congestiflora, both almost identical plants containing several alkaloids but little or none is known of its ritual use.

I think your information will be my starting point for finally trying it in a proper way (loved the idea of making and extract of it and smoke it with tobacco), as I've only smoked a few dried leaves some years ago but no effect was perceived.

Let me know if I can help you in any way with your own research on this plant! Best