Asklemmy

Depression isn't the same thing as sadness, and I wouldn't be surprised if it disqualifies someone from being an astronaut. Most people don't have depression, but everyone feels sadness at some point in their lives.

To answer your question, astronauts are trained to work under extreme stress, so they would know how to compartmentalize the pain and focus on completing the mission. Similar to soldiers.

They have to be re-pressurized in the pressure chamber.

This isn't a direct answer to your question per se, but if this a topic that interests you, I can't recommend The Right Stuff enough. I've not seen the film from the 80s, though by all accounts it's pretty good, but the book is an excellent overview of the early days of space exploration, when the exact sort of questions that you ask here were being bandied about by the fledgling, pre-Apollo program NASA.

The focus of the book is on the first wave of astronauts who, as someone else mentioned, were pulled primarily from combat aviation backgrounds. I recall several passages which detailed their reactions to the sorts of psychological testing that they were undergoing, usually complete with humorous anecdotes.

nasa employs psychologists.

or at least they did until conservatives decided to fuck everyone over.

Besides what everyone else has said about screening, I'd suspect the astronauts are pretty cut off from the world.

If ground control can control all communication, what's to stop them from censoring?

People with depression still doing their job everyday. Idk how much of a difference space would be. Maybe worse depression?

Psychological screening likely has a strong bias against this situation. One of the key aspects of selection is personality compatibility and how a person responds under great immediate stress. Astronauts are the people that are calm and totally under control while the craft they are flying is disintegrating around them. That is why they were first selected from the ranks of military test pilots.

People process these things differently too. I am very depressed because of my physical disability, but it is entirely circumstantial and nothing can change that circumstance. The only real issue in my situation is if a person is unaware of the effects that depression can have and it causes negative actions. I have meds I acquired just by asking my general practitioner. I've had a couple of bouts of existentialism in a negative spiral. Taking meds dulled me until the circumstances changed. In my situation, this is the only real treatment; just dull the person medically. I'm generally more self aware than most people seem in this respect, but I think you will find a similar type of trait in astronauts. The person's Machiavellian scale will have an effect on how they process emotions against their functional thought and personality too.

I'd assume lack of normal gravity would have a measurable effect on brain chemistry

I think I watched a documentary on this, not sure if it was the ISS but something like this already happened and they literally duct taped the hatch closed as a precaution.

Worse case scenario I imagine the procedure would be to duct tape the person up so they can't do anything stupid.

There's an escape hatch. If they get too out of control, the other astronauts launch them out the door. On the side facing earth, so they don't become space debris. They burn up in the atmosphere, and pose no risk anymore.

Relevant Black Mirror episode

Why wouldn't you steamroll over it?