OP, were you given a diagnosis by a doctor, or do you surmise you have this based on a self-assessment? The "official" threshold is six months of serious constant symptoms, and
only after all other possible medical or environmental causes have been ruled out. Also, if you're not yet past your early- to mid-20s, it may not actually be schizophrenia.
Sometimes hallucinations (hearing voices or other unexpected sounds, seeing imagery without actual sensory input) can be caused by sleep deprivation, very high caffeine consumption, or malnutrition, or habitual isolation. If relevant, it would help to address these possible causes first.
Sometimes delusions (unfounded beliefs about self or others, especially of a harmful or frightening sort) can be the result of
reversible depression or mania or anxiety, or over-exposure to certain forms of media or emotionally harmful social interactions. (I say "reversible" because schizophrenia differs as it's assumed by psychiatrists to be a lifelong condition. Then they will try to prescribe long-term medications that have their own debilitating metabolic and neurological side effects.) If possible, try to explain your symptoms to a traditional priest, who may be able to identify any spiritual factors for what you've been experiencing.
As to some of the nutritional advice that others have posted earlier, note that
most of the vitamins absolutely necessary for neurological health are fat-soluble. If you stop consuming fats, then these vitamins can't be absorbed, whether you get these vitamins from food or from supplements. What kind of fat you eat matters. Stay away from vegetable oils except for coconut or olive. Be sure you get most of your fats from dairy, fish, and meat; if at all possible, try to get the dairy/meat fats from grass-fed sources.
As for sugar and carbs, these might reduce cortisol in the moment
only insofar as these can momentarily reduce stress as a quick "sugar fix". However, daily over-reliance on refined sugar or processed carbs will
increase cortisol if these calories are stored as abdominal fat, and they'll also make you constantly hungry no matter how much you eat. Therefore, if those sugars and carbs don't come with vitamins built in (as in fruits or root vegetables), these will do more harm than good.
If this will be your cross to carry, no matter what happens: please remember to keep to a simple yet diligent daily prayer routine. In this too, a traditional priest can advise you which devotions would be most appropriate and helpful for your situation.
