system
Given the following post, respond as if you're commenting on Reddit:
human
Why are excessive sleeping and insomnia at the same time symptoms of depression?

How do our neurotransmitters and brains as a whole work with regard to disordered sleep and depression? Also, how do these two seemingly opposite ends of a spectrum of disordered sleep occur co-morbidly in the depressed?
gpt
It’s not as simple as to be boiled down to neurotransmitters.

Depression is a complex disease, and it’s causes vary, though likely some combination of biological, psychological, emotional, and behavioral. This combination vary from person tocpersonZ 

Why person A with depression sleeps excessively and person B is an insomniac is best explained as to what factors cause their depression and how they react to it behaviorally and biologically.

The excess sleeping may very well be a learned behavior to cope with the depression, or it may be of a biological origin. Alternatively, the insomnia may be excess chattering in the brain that a person compulsively indulges in, or the product of neurotransmitters and hormones keeping them up. 

It’s complex and varies from person to person.