You are asking a broad question with a lot of answers depending on the country or state or jurisdiction. As far as the movie if you're talking about Eddie, (YouTube), it appears he used an oral method of pentobarbital. It didn't say where he was but I suspect it was Dignitas (Switzerland, he flew into Zurich). Some countries like "Benelux" (short for Belgium Netherlands and Luxembourg) may use injections, in which case the term euthanasia would apply. The Swiss associations only allow assisted suicide. In the US everything is oral. In the US you have to have a 6-month death sentence (doctors say you are terminal within 6 months). In the US there is a cocktail of drugs used now (they used to use seconal or nembutol, discontinued because of the capital punishment industry). Canada has more options to qualify but it's still pretty restrictive compared to the European countries. Even there, you need to be pretty sick with something that can be supported by medical documentation. Mental health issues are difficult but not impossible. That's my short answer, as I best understand the current situation.
