If we consider Wikipedia a reliable source, especially on a sensitive topic and on a person like Adolf Hitler, there is no room for speculation, but only factual information.
Looking at the Wikipedia page for Adolf Hitler on the health section. We can be sure that if Ian Kershaw, one of the top historians about the Third Reich and Hitler, did not find any convincing evidence about Parkinson's disease. He believed he might have suffered from Parkinson's disease, which is what he wrote in his book, but he found no compelling evidence. He was able to remove fact from hearsay and speculation, which is what we should do.
A movie script, has the freedom to use the speculation and other wild stories to make the script more exciting, and to make you love/hate/understand the main character better.