cheesymuffin's comment is downvoted, but I think he's on to something. It would be very odd to consider inflammation of the brain to be a cause of any problem, because inflammation is a symptom of something else.
Being a symptom doesn't absolve it of being a cause too. If a thousand things can cause inflammation, but then there's a package of symptoms caused by inflammation itself, then it could be worth it to directly fight the inflammation in a lot of cases.
Inflammation often is directly causative, for example atherosclerosis where the inflammatory response directly results in the buildup of plaques. Inflammation is not typically the root cause, however; something else instigates the inflammation.
The distinction matters because the best treatment (greatest efficacy, most cost efficient) may target one or more of the links in the causative chain, but not necessarily the root cause.
Yeah I agree, however I'd imagine if inflammation was the cause of issues (and I recall some studies showing brain inflammation to be linked to some brain disorders) then perhaps more research would go into what causes the inflammation.
Some evidence the inflammation might be diet related too. Although I can't recall the source at the moment.