Do you mean a quarter turn...to form a T, rather than side by side?
I agree it isn't normally done, but hey, why not? Anyway, either way, stiffen both of those studs, hinge and strike side.
It probably isn't done because it would give you less "meat" to attach the casing to. Casing will typically be around 2 inches wide and sometimes a fastener is desired about 1-1/4" from the edge as well as close to the jamb. Doubling the studs in the traditional manner would provide the needed meat to nail to.