Schizophrenia does occur in the brain, yes.

However, there are medical conditions that often cause major changes in behavior. Those possibilities need to be ruled out ~ to protect your physical health ~ before moving on to treating the psychological aspects of this disease.

There are several other illnesses in which more serious causes need to be ruled out before diagnosis and treatment begin. For example, seizures can be caused by drugs, brain injuries, brain tumors ~ doctors begin testing for these possible causes before beginning treatment for epilepsy in order to prevent seizures from recurring. Other possible causes must be ruled out to be sure that the correct treatment is chosen.

Regarding finding schizophrenia within the brain, PET scans do show that those with schizophrenia have similar flares of high energy in certain areas of the brain. While the results of the disease are mental disturbances, the cause is physical changes within the brain. Just like tests show that those suffering from clinical depression have physical changes in the brain ~ the neurotransmitters that make us feel good are blocked and there are less open synapses to absorb chemicals that do transmit positive feelings towards life. Those are physical changes within our brains.

I hope that this wasn't too technical for you and makes better sense to you now. Best wishes!