My mother was diagnosed with Schizophrenia at a very young age and has suffered from the condition for over 40 years.
I am 19 years old and seeing gradual changes in my behavior patterns. These changes could be due to growth or hormonal changes given my age, however, given my inherited traits this could be cause for concern.
Am I at a great risk for developing Schizophrenia?
What can I do now to prevent/inhibit onset?
You have a lot of insight and maturity for a 19 year old, and it is good you are taking care of yourself. I'll answer your two questions in turn:
1) Your risk for developing schizophrenia, on the basis of having a parent with schizophrenia, is about 10 to 15%. This means you have an 85 to 90% chance of not developing schizophrenia. However, having any sort of psychotic-like symptoms (suspiciousness, overvalued ideas, perceptual illusions) would increase your risk.
2) As for preventing (or delaying) possible onset, I have several comments. First, I don't know what sorts of changes you are having in your behavioral patterns. If these are problematic for you and are like "symptoms" or interfere with your function, then you should have these addressed.
For example, I am the director of a program for young people who are at increased risk for psychosis and schizophrenia, as compared with their peers (which you are, simply because your mother has schizophrenia). My program is called COPE and is in NYC (212 543 5874). There are a number of programs like this across the US and worldwide -if you go to schizophrenia.com, you will find the program closest to you. You may find such a program helpful for getting expert advice and - if needed - treatment.
Also, there is evidence to suggest that use of drugs, especially cannabis, may lead to onset of psychosis in individuals with some vulnerability to schizophrenia. So abstaining from drugs is something you can do, which is probably a good idea anyway.
Other than that, simply maintaining good mental health is your best bet. Get treatment for any symptoms of anxiety or depression you have, or if you are having trouble coping with stress in your life.
Thank you for your very good question.