Yes, especially social anxiety. We are genetically social and we are supposed to socialize. It has come from our ancestors when they started the idea of hunting động vật in groups in order to gain thêm safety. Whenever someone was excluded, they used to experience in great despair and fear of danger. That's how it came down to us.
First hand experience, I can say that it depends on what loneliness is to you.
bạn can be lonely in room full of Những người bạn if its deep rooted. To me, that's what distinguishes it all. Sometimes it can bring paranoia, and other times it can turn a usually social person into an awkward mess of a person because despite what people may think, bạn CAN lose the ability to socialize (or rather forget how to).
But I've also found that (being that my major used to be one in psychology), that this is something that can also be handled. Once bạn think of "loneliness" as something else other than that, then it can actually bring about a sense of peace and awareness. There's a lot thêm that goes into it, and many things to take in account overall.
Loneliness can definitely cause nervous, depressive, and anxious breakdowns very very easily especially if it is long term, almost constant, and even thêm so if it goes against your nature. Some people are thêm comfortable / introverted and have a larger resilience against being negatively affected bởi loneliness and thus can tolerate it thêm than others where as some people have a high need for social interaction and just a week without talking to people can send them into a negative mental health spiral.
As for psychotic breakdowns, I have yet to properly research into it properly, but I would say it is a possible stressor that could trigger a "dormant" predisposition to a psychotic disorder hoặc psychotic symptoms hoặc it might work in tandem with another disorder (such as Bipolar I hoặc II with Psychosis) as it might raise the frequency of extreme depressive episodes that in turn cause psychosis.
I wouldn't necessarily say they can produce / cause psychosis as there tends to be a predisposition that has to be there, but they can probably trigger a pre-existing mental health condition that was either not as extreme hoặc dormant. With that being said, psychosis is my weakest topic on mental health so I may hoặc may not have gotten a detail hoặc two wrong there.
It also partially depends on your age that isolation and loneliness occured. In extreme amounts at a young age it can cause severe issues in further development into an adult and result in traumatic disorders and dissociative disorders.
Dissociation is often confused and mixed with psychosis as there is a degree of overlap especially with how they project themselves outwardly but one matches with a disconnect from reality (I dont feel like part of the world, I am not here, I don't feel my emotions, etc) and the other is a distorted sense of reality (delusions of grandeur, god complex, paranoia, etc)
TLDR; Social interaction is a very important part of a human's health both physical and mental and having such need extremely depleted can cause the brain to do weird shit sometimes and if at a young age when the brain is very neuroplastic, it will adapt in equally weird ways.