system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter]Dementors make humans experience extreme depression, that being the case how do they keep people in Azkaban from just lying down until they die of hunger/thirst?
gpt
The effect of a Dementor probably isn't on/off so much as an intensifying area of effect enhanced if the Dementor is focusing on you... If you're further away and there's only 1, and it's not actively draining you it'll take longer to set in and probably won't be as profound.

There's a passing comment by Fudge, when he's explaining the Black situation to Madam Rosmerta in "The Prisoner of Azkaban", and he says Black was given maximum security, with Dementors outside day and night.

Extrapolating from that statement, there are patrols of Dementors throughout the place, with at least standard and high-security, maybe other denominations. The Dementors may not necessarily enjoy feeding on someone 24/7 as much as letting them recover somewhat before bringing another crashing wave of cold, despair, misery and eventually apathy on them. So, some of the prisoners may be largely left alone and only experience a partial or cyclical effect. It'd probable still be pretty horrific, even if it's not as intense as having the Dementors there all the time.

And Black did mention that within a few hours people went from defiant, to miserable to screaming for someone to help them. Eventually even the strong-willed ones succumbed to apathy and stopped screaming. Some of them stopped eating. He also said the Dementors could sense when death was approaching, and behind excited, gravitating towards the person they'd managed to tip over the edge.