Does being unable to yawn make you drowsy?

the silence speaks volumes. guess it's just me, who gets extra drowsy when I can't yawn

Yes. I always figured it made sense, after I read an article that talked about how a study posited that yawning helped bring more oxygen into the body, which would temporarily make you more alert. So based on that, I figured it made sense why you'd get more tired, if you couldn't yawn.