joints, eye and brain are sweet spots for any infection, because if they get there, they are extra protected by the lack of immune response: the joints are too dense for immune cells to easily pass, the eye is protected because vision interferes with immune processes, the brain tissue is delicate so immune cells are limited.
so yes, if your bacteria gets trapped in the brain and your immune response is strong enough, it won't spread and will give you mostly neuro symptoms.
btw i had no idea extreme fatigue is a psychiatric issue. You're telling me after a marathon these guys are not physically fatigued ? They very much look like their entire body is wasted. So if you have problems removing toxins, you have too many an infection and immune response that produces them, then your fatigue is very much physical, not mental !
I would misdiagnose fatigue as some endocrine issue, but not psychiatric. Well, what do i know ...