A rational decision is weighing the pros and cons. If you are blind to your illness (and the ramifications, for example having killed a family member you care a

A rational decision is weighing the pros and cons. If you are blind to your illness (and the ramifications, for example having killed a family member you care about because you believed them to be a demon), then how can you weigh the pros of having those delusions resolve vs the cons of weight gain and potential diabetes? It's not always irrational to refuse, but a total absence of insight into illness precludes a rational decision.