Doctors say Dave is suffering from nervous exhaustion. Specifically, he has Obsessive Computer Fatigue Syndrome.
There is some talk about making OCFatS a registered industrial disease as it only ever afflicts IT workers. In a techie aria, such as supporting a full-blown enterprise Linux infrastructure at Bogcaster City Council, everything is far too complex for any casually engaged person to truly come to terms with it. But anyone prepared to devote their life to it becomes indispensable.
To maintain their position this person must spend more and more time working. Eventually everything else in their life backs into the shadows and their personality becomes inextricably connected with their system.
Although they may appear in control, the pressure is buiding up internally. Then, if they start to lose even the smallest element of control, they just fall over. Dave has "retreated into a state of reduced consciousness" or, as Mavis puts it, "he's gone bonkers".