You can have a different reaction weeks into a set drug regimen. Plenty of other factors can change. Dosage. Lack of sleep. Diet. The specific times you take things.
I don't much care either way (he should not drive impaired - that puts others in danger) as it's off-course stuff, but I still like facts and dislike speculation.
Haven't been to a driving range yet this year and went out to play my first round of the year on Sat. No warm up just right to the first tee and bam, nice lil fade to about 100 yards. Drop it to 4' and I am putting for a birdie! WOW! What a way to start.
Second hole I pared, third hole I pared as well! What is going on I thought? Bogey most of the other holes with a real bad triple but end the front with another par. 42 on the front is looking good!
Play about the same on the back with a lot of bogeys and 3 more pars and end with a 43.
85 my first time out this year was sweet! Only missed 1 fairway and was 14 & 15 for putting.
Put me on the side of "not a head case".
He's going through some putter changes right now so I'm attributing some of his struggles to that. He's still 32nd in strokes gained putting but that's his worst performance since 2013. He's actually 2nd in strokes gained for approaches to the green. Off the tee is where he has had his struggles. Now and in the past.
Has he been a little inconsistent this year? Sure, but calling him a head case is a bit strong in my opinion. If you wanted a head case I'd argue that Bubba Watson would be a much better example. He's now 125th in FedEx Cup points and all the way down to 34th on the OWGR. Three behind Tommy Fleetwood and five behind Bernd Weisberger.