Welcome to the site.
I am Dr. Kaushik and i believe i can help you with your query.
Well, first of all I am sorry to learn about your son's condition and i pray that he recuperates well and remains symptom free.
Now before i come to answering your question i will like to throw some light on the difference between Bipolar disorder diagnosis vs. Schizophrenia. You see a Bipolar disorder is diagnosed when a person develops a manic or a hypomanic episode with or without psychosis , so basically speaking Bipolar disorder is a Mood disorder while Schizophrenia is an out and out true psychotic disorder. So both of them are different since they come under different categories and yes bipolar disorder is considered to have a more favorable outcome as compared to schizophrenia. Now, other than these two disorders there is a third disorder called as Schizoaffective disorder which is a condition which has characteristic features of both bipolar mood disorder as well as schizophrenic psychotic disorder and it is considered to be mid way between these two disorders in terms of severity where bipolar disorder is considered as least severe with a better prognosis while schizophrenia as the most severe and between them lies schizoaffective disorder.
So what you read about change of his diagnosis to schizophrenia from bipolar disorder if the episodes continued in future is not wrong but it needs some more specific understanding and that is, if his continues to have manic episodes mixed with psychotic features then his diagnosis may have to be shifted to schizoaffective disorder which will be more justified diagnosis than schizophrenia or bipolar disorder but it will still come across as having chances of better outcome than schizophrenia. But having said that thorough evaluation by a psychiatrist is essential to reach a conclusive diagnosis , so i reckon please do not be in haste to reach a diagnosis and wait and watch the course of your son's illness but continue to provide him with treatment so as to prevent the illness from spiraling out of control.
Now coming to your main question and the answer is YES , stress can very act as a precipitating factor for development of future such episodes thereby worsening his condition and making it more severe. So i suggest that you try your level best to convince him to avoid stressful situation like his tension ridden job so that future such episodes can be avoided. May be later once he has become symptom free and his symptom free state has been consolidated, he shall get back to job after approval from his doctor but at the moment he is at the beginning stage of recovery where he has only passed a short period on the treatment.
I hope this helps.
Wish you all the best.
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