What does inpatient treatment mean?Watch
You wouldn't be "forced" to go anywhere unless you are being sectioned under the Mental Health Act (and you'd know if this was happening), or if you are under 16 (in which case, your parents decide everything for you). If you are over 18, then nobody can force you to do anything. If you are between 16 and 18, then it's a bit of a grey area - it's between your doctor(s), your parents and you, basically.
Nobody will be pumping meds into you for depression, don't worry: at most, you'll be offered a fairly basic anti-depressant (Prozac, Zoloft, Fluvoxamine, what have you) which, to be perfectly honest, won't make that much difference as true long-term recovery from depression lies in therapy, rest, and your own efforts to get back to a normal life (not medication alone).
If you're worried about literally being drugged against your will, then I assure you that this won't happen - at least, definitely not in the UK - unless you really are out of control and a danger to yourself or others (you'll know if this is the case). Even then, though, you really shouldn't have any extreme experiences wrt treatment: a friend of mine was sent to one of the more "serious" psych wards around a year ago straight from A&E, and all that happened to her was that she lay around on the ward with 24-hour observation for two months and took medication (she has schizophrenia though, so the medication situation there is very different to depression).
In short, from my own experience and certainly from everyone I've spoken to, inpatient treatment is really rather dull compared to what most people think it is. After three months or so, most people are bored out of their minds in IP.
(That is, of course, in "regular" places - I've never spoken in detail to someone who's been in a high-security place like Broadmoor, but I'm fairly certain that you're not headed there because they treat severe personality disorders more than anything else, apparently.)
If you want to talk more then do PM me - I have nearly two years of IP for depression behind me and would be more than willing to help. I'm sorry if this post didn't make much sense - what I wanted to do was reassure you that IP treatment is not something to be scared of, and that if your medical team and/or family think you would benefit from going, then really do try and go.