Are there foods that can be useful in treating schizophrenia?

no.
There are possibly some food allergies that can mimic in a minor way some of the symptoms of psychosis, but there are no food that can be useful in treating schizophrenia. Nor are there any foods which make it worse. Drugs and alcohol yes, but foods, no.
There is not a lot that is definitively known. This study Schizophrenia and depression affected by diet concluded that <blockquote>Quote
<hr>a greater consumption of refined sugar was associated with a worse outcome of schizophrenia and a greater prevalence of depression. Other correlations for outcome of schizophrenia include consumption of meat and eggs (adverse relationship) and consumption of pulses (beneficial relationship). Dairy products and alcohol consumption were associated with a poor outcome in [one] study, but not in [another] database.
[snip]
The dietary predictors of outcome of schizophrenia and prevalence of depression in this study reflect dietary patterns that influence insulin resistance, in particular, consumption of large quantities of sugar and saturated fats, and lead to metabolic syndrome diseases.
It may therefore be that altering diet could have a positive effect on mental as well as physical health.
There is anecdotal evidence that diets that do not lead to insulin resistance may be useful in the treatment of schizophrenia (Meiers, 1973). Omega-3 fatty acids, found in fish and seafood, have recently been shown to have strong positive antidepressant benefits (Nemets et al, 2002; Peet and Horrobin, 2002).
Whether the relationship between nutritional factors and mental health is causal can only be determined by intervention studies<hr></blockquote>In other words, there might be certain diets that help with mental health issues, but we don't yet know enough. As one of the authors of the study said “Association does not prove causation”.
Note that they are talking about diet, not individual foods. Some "nutritionists" of dubious qualifications have used this study to justify recommending various foods and diets, but the authors of the study made no conclusions on which such recommendations could be made.
Schizophrenics often do not eat well in general. Psychiatrists from the Clark Institute of Psychiatry at the Univ. of Toronto say <blockquote>Quote
<hr>What is the best diet for people with schizophrenia? Some individuals with schizophrenia adopt a monotonous diet, eating the same food daily, gaining very little pleasure from taste, or attractive preparation of a meal, snacking on potato chips, chocolate bars and candies. Even worse, they don't eat enough. This may occur when they are actively psychotic, fearing their food is poisoned.
Limited and poor nutritional intake is of concern to clinicians and relatives. We all need good food and a balanced diet. This keeps our weight under control and will likely benefit other medical conditions such as blood pressure, diabetes, dental problems, and constipation, among others.
To ensure that isolated patients have access to food, daycare/aftercare programs often provide nourishing snacks to groups, e.g., green vegetables, cheese, milk, juice, water, fruits, sandwiches etc. At the same time, it is wisest to serve no stimulants such as coffee, tea, cocoa, or soft drinks. Learning shopping and cooking skills is also encouraged. In cases of emergency, most communities have some sort of food bank where patients can be referred for free groceries.<hr></blockquote>
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<hr>Are there foods that can be useful in treating schizophrenia? <hr></blockquote>
I've heard that fish oil is good. As I haven't tried it myself I'm in two minds about it.

There was an early study which suggested that in populations that ate a lot of fish there was a reduced incidence of schizophrenia. This has not been replicated and unfortunately some places where fish is a major staple there are very high incidences of mental illness- pacific islands for example. And yes there is some suggestion that omega 3 may be of some help although the evidence is still out. Most nutraceuticals cannot hurt and may help. And nutrax is certainly right about the poor diets which combined with the effects of medications can and often do lead to diabetis.
We know that the phospholipids in the neuronal membranes of the brain are rich in highly unsaturated essential fatty acids (EFAs). Omega 3 fatty acids are a family of polyunsaturated fatty acids which have in common a carbon-carbon double bond in the omega−3 position. These are essential fatty acids, meaning that the body does not make them and people need to consume them.
It has been hypothesized that abnormalities of phospholipid metabolism are present in patients with schizophrenia and that the EFAs omega-3 polyunsaturated fatty acids, and eicosapentaenoic acid (EPA) in particular, may have a role in treating this illness. But the studies to date (of which there have only been a handful and none particularly well designed) do not support the use of omega 3 fatty acids or EPA for the treatment of schizophrenia. The issue of whether these fatty acids would be useful in preventing the development of schizophrenia has not, to the best of my knowledge, been addressed at all.
On September 8, 2004, the U.S. Food and Drug Administration gave "qualified health claim" status to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) ω−3 fatty acids, stating that "supportive but not conclusive research shows that consumption of EPA and DHA ω−3 fatty acids may reduce the risk of coronary heart disease. In addition, there is a promising preliminary evidence, that ω−3 fatty acids supplementation might be helpful in cases of depression and anxiety. There are studies reporting highly significant improvement but again there has been no conclusive evidence presented thus far. There is also a small but well designed double-blind placebo-controlled study of persons with bipolar disorder whose recovery improved with omega 3 fatty acid supplements.
Please check your PMs.
Ruth, and yes, I am a psychiatrist
