How do people get Schizophrenia?!

First off, schizophrenia is not stress-related, at least not in the basic sense. It can be brought on by a psychotic episode, which is stress-related but not in the "i feel stressed out" kind of way. This would be severe social and psych-social stressors causing a psychological breakdown in someone who is already pre-disposed to serve psychiatric illness.
The pre-disposition part is most significant. Our brain matter is quite complicated stuff, and our neurons are constantly firing to send messages from the brain to other parts of the body. In schizophrenic patients, there is inaccurate information being passed long. For example, psychosis would mean the patient sees or hears things that aren't here, usually accompanied by believing things that don't exist. It is not your fault if you have been diagnosed with schizophrenia, and it is not curable. However, these symptoms of psychosis, hallucinations and suspiciousness can be best-controlled by antipsychotic medications.
On the subject of inheritability, these illnesses are not inherited per say, but mental illness in the family-especially parents and grandparents-can indicate a likelihood that their children may have mental illness, whether mild or severe. In other words, you are not "doomed to be crazy" if your mom suffered from lifelong major depressive disorders, but it does increase the likelihood for who as opposed to a friend with no mental illness in his family.
It is all a matter of chemical imbalance in the brain. A great place.to look up more imo is the National Institute for Mental Health. Nimh.org I think

Continuing education credits, National Institute for Mental Health and daily psychiatric research

It is inherited. You should see a Dr. Phil episode on Schizophrenia. Just type on YOUTUBE.COM and click on the episode that says Schizophrenia.

The disorder gets worse when stress is greater on the person. Medication and therapy make it possible for sufferers to live a very normal life.

For anxiety disorders, it could be inherited but I think its psychological given to the child. People teach their kids what to be afraid of. If they happen to be always fearful and worried, it won't be surprising to see the child also be ****** up.

Or genetically/biological/behavioural/upbri… Even top psychologists/scientists still don't REALLY know the answer to this??

It's a biological thing, usually inherited or something that develops over a period of time.

Most times mental illness is genetic.
Sometimes they can be stress related.

There currently is no know cause or cure for schizophrenia.

Biological usually. Some are hereditary and some develop over time.

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