I too have PsA and find smoked/vaporized cannabis has minimal anti-inflammatory properties, but works nice to aleviate pain and other assorted issues.
But, a daily regimen of raw juiced cannabis (of Specific CBD dominant strains) does wonders for not only the inflammation, but at controlling the root of the disease too.
Check out the work of Dr. William Courtney (www.cannabisinternational.org
)...it discusses this stuff in more detail.
For me, it's bee life changing!