Starting in the second season there was a somewhat of a running gag of Barney sleeping while on the job. In season two there are two funny instances of Andy playing pranks on Barney while he's sleeping on the courthouse cot and one where Barney's sleeping on a bench outside. Andy even brings this up when the "journalist student" is there in Andy on Trial by saying the cot in the back is where "Deputy Fife likes to take his afternoon naps"

Two seasons later in the Season 4 episode Up in Barney's Room Mrs. Mindlebright mentions that she's seen Barney sitting in his room in the middle of the night with his 55 watt lightbulb on and accuses him of being afraid of the dark which causes Barney to yell "Snoop! Snoop!" The interesting thing is in Season 3's Mountain Wedding Barney had no problem sleeping when he spent the night at the courthouse. He also would have no problem sleeping when Otis called him in the Season 5 episode The rehabilitation of Otis.

Seeing these instances make me wonder if Barney suffered from feelings of paranoia about the dark. It seems like if he could get to bed early enough while people are awake/the light is out he's okay, but anytime after 10:30 it seems like he's scared of falling asleep, which results in him having to sleep at the courthouse/on benches during the day. I also wonder if the feelings of Paranoia might've been Knott's idea given his father came into his room in the middle of the night while have a shizophrenic episode and tried to kill him while Knotts was sleeping.

To many late nights with Thelma Lou.