Euthanasia clinics in Switzerland- do you need to be terminally ill to go there or can u go there for any case?

Heard there is a euthanasia clinic in Switzerland called Dignitas. When browsing on Google out of curiousity, it didnt really say alot, except for an article saying that over 700 people had killed themselves there, and residents had been complaining about this or something. Anyway, I am wondering if these clinics are specifically for those with a terminal illness, eg incurable cancer, OR if anyone who feels they have a "purpose" to take their own lives can do so, eg mental illness/disorder that simply isnt getting better or being helped with meds. Are clinics like these more than happy to take your money (if you pay?) for whatever the case, or as I have said, need to be specific? Thanks