"Nobody has ever found a specific brain abnormality that all schizophrenics have that nobody else has, " he said.

BBC: Artifical brain to spot schizophrenia

There's no known way to correct the underlying brain abnormality that causes dyslexia.

CNN: Dyslexia

Sudden changes in mood or personality, visual hallucinations and alternations in smell, taste or tactile senses could signal a brain tumor or other abnormality.

WSJ: Confusing Medical Ailments With Mental Illness