We currently have an informal patient who has capacity in our Acute Mental Health Hospital. We have been monitoring their eating and drinking since admission due to the lack of food intake ( nothing was noted on referral information in regards to lack of food intake) Fluid in take is very good. As a service we are concerned as the patients weight has decreased from admission and is continuing to do so. We are looking to refer out possibly for an eating disorder bed, however in the mean time what I would like to know is were do we stand on the legal side if the patients health was to worsen, she is informal and has capacity but refusing to go to a physical health hospital for treatment and the same question if the patient was detained?
Thank you
I suggest you need to explore the reasons for not eating with the patient as part of assessing her mental capacity, as you cannot rely on the presumption of capacity. If you still believe she has capacity, you will need to consider whether her refusal to eat is a symptom of a mental disorder, which meets the criteria for detention under the MHA. If she were detained under MHA, section 63 allows you to provide treatment for the mental disorder, which could include treatment for the physical effects of food refusal.
Also whilst informal, any referral to an eating disorder place would be with the patient’s consent and couldn’t be done without it.
Thank you both for this information. 
Following on from Stephen’s suggestion i would highly recommend the following Capacity Assessment guidance Practical legal guidelines - Capacity guide and you will likely find the ‘Typology of Capacity Rationales’ outlined at paragraph 33 of interest.