If the neck was set up for 'thicker' strings and you're now set with a lighter gauge, then yes, it's possible the truss rod might need adjusting. How straight is the neck generally (front bow, back bow, level), with the strings tuned up? How is the fret buzz near the neck and higher up the neck towards the bridge?
It's feasible that with the truss rod too tight, you might have some back bow on the neck which will cause the neck to arch away from the midway point; so somewhere around your 8th fret. The graphic below is pretty succinct. If you're doing this yourself, detune, turn the truss rod a quarter turn anti-clockwise and tune up :: lefty loosey, righty tighty :: repeat if necessary.