Does the word "chuunibyou" originate from the anime "Chuunibyou"? I was reading Black Lagoon and realized that Lotton is a bit like a chuunibyou. He called himself "The Wizard" and he always wanted to make a cool entrance before a fight but usually got his ass kicked quickly. In my opinion, he's a chuuninbyou. But no one ever mention that he's chuunibyou. 

(Or probably he's not chuunibyou after all, but keep that for another question.)

Being the earlier anime (Black Lagoon was aired in 2006 while Chuunibyou demo Koi ga Shitai! was aired in 2012) it got me thinking about whether the word "chuunibyou" actually originated from this anime. Or probably it was not just as popular as now.
No, the word "chuunibyou" was not coined by the anime Chuunibyou demo Koi ga Shitai! (nor by Black Lagoon). The term is attested back to 1999. (For further reading, the TVTropes article linked in Aki Tanaka's comment seems good.)

Data from Google Trends seem to indicate that searches for this word were low but slowly rising until October 2012, when searches spiked (because that's when Chuunibyou demo Koi ga Shitai! premiered). Search volume for "chuunibyou" has since fallen off, but is somewhat higher than it was just before October 2012, even after you subtract out searches specifically for Chuunibyou demo Koi ga Shitai!. My point here is that in 2006 (unlike now), the word "chuunibyou" had very limited purchase and it is hence unsurprising that it would not be used in Black Lagoon.