“One of the most studied ideas as to what causes schizophrenia is the 'chemical imbalance theory,' which derives psychiatric pharmaceuticals themselves. Though the 'mechanism of action' of drugs marketed for their 'antipsychotic' properties isn't understood--plainly, drug companies believe these drugs are effective in lessening psychiatric symptoms, but they don't actually know why--what is known is that they affect chemical levels in the brain. It's therefore supposed that abnormal chemical levels might somehow be crucial to understanding what's different about the brains of people diagnosed with schizophrenia. Testing chemical levels inside brains remains impossible. Despite billions of dollars of investigation, the chemical imbalance theory has never been confirmed.”