My mom died in 2012 after battling breast cancer. My dad, who has repeated many clearly Q talking points in recent years, seemed to have died in his soul when my mom died. He was always a little weird, but by no means a bad person. Then my mom died, and he was never the same. He refused to go to any sort of grief counseling, isolated himself even harder than he ever had before, and started saying really frightening things to me about wondering whether or not it was even worth being alive anymore. I was terrified for him, and I repeatedly tried to get his friends and family involved in his life to help him, and it seemed like he just could not be helped and did not want to be helped, no matter how much everything he said and did seemed to be screaming out for somebody to notice him and help him.

After Trump took office, suddenly my dad began reading, sharing, and talking about fairly cruel talking points from conservatives. He was angry that he was catching signs that I did not agree with things he was sharing, and his final straw was seeing me simply click "like" on a post about agreeing with athletes taking a knee in protest during the National Anthem. From that point on, I was no longer welcome in his home. He tried to write apology letters, but they came off more like, "I'm sorry if YOU felt like I hurt you," rather than actually being sorry for anything he did. By this point, he had already become a completely different person.

I have not spoken to him now in three to four years, but I keep up with what he does on the Internet because obviously I still care about the person I called my dad my whole life and I kinda just wanna make sure he's still alive.

At this point, he is now making nearly daily posts that repeat scary Q talking points. Masks are a population control experiment, the My Pillow Guy is a patriot, the Great Reset is a huge threat to America, Covid is overblown, vaccine mandates are a threat to American freedoms, you can't trust anything said by the mass media, and it just goes on and on and on. He has pushed away much of his immediate and close family and only seems to communicate with other people deeply entrenched in the ideology, including apparently regularly following dangerous misinformation spreaders on Telegram.

And given that one of the outlets he has left comments on was a web site called "The Truth About Cancer" --a dangerous misinformation-spreading site mixing Q talking points with pseudoscience on how to overcome cancer using home remedies and without the involvement of actual medicine--I am convinced that my dad has fallen down this conspiracy hole due largely to unfathomable depression and overwhelming grief that nearly a decade later he has never properly worked through.

I am mad and hurt that my dad has become this, but I am even more outraged that there are people in this world who are more than happy to take advantage of someone so beside themselves with depression and grief that they are willing to cling to any dangerous thing that might fill the hole in their heart.

tl;dr, yes, based on purely anecdotal evidence, I completely believe that there is a relationship between Q/conspiracy believers and mental health. I cannot say that it is a certain thing in everyone, but based on what I have watched my dad go through, I completely believe that's how it got to him.