Cde
You are correct that you are entitled to refuse treatment, further there are very, very limited circumstances where a Decision can be made taking into account the effects of any such treatment.
Have a look at the following Disability Allowance fact sheet, specifically section
6.8 Refusing treatment.
www.disabilityalliance.org/dlalaw.htm#treatment As always, when referring to benefit case law, you should make sure you fully understand the implications of the case(s) in question, before referring to it.
Gordon