Questions like this have no simple answer that applies to all patients – medicinal cannabis affects people differently enough that beyond general observations regarding certain strains (like stimulating or sedating) it is definitely a matter of personal experimentation. PTSD symptoms may even respond to the essential oil (terpene) content of cannabis, which may be a better marker than "strain" for what a given patient finds helpful. My advice would be cautious experimentation, and if a cannabis variety seems particularly helpful I would explore related varieties looking for similar effects. I’d also pay attention to the CBD content of the cannabis, as particularly in PTSD situations adequate CBD needs to be present to modulate THC effects.
drelkind