I had a friend who had advanced, terminal cancer. She decided that rather than spend her last days sick from chemotherapy and drugged on morphine for the pain, she would live as long as it was bearable and then end her own life. I don't think she was depressed. She was someone who loved life and had always accepted what it brought with gusto. She simply wanted to die on her own terms, peacefully, and in her own way. I had another friend who was in terrible pain from a bad hip and was told she was not a candidate for hip replacement. She hated the immobility and the constant pain, and made what she considered to be a rational decision to end her life. She asked another friend to help her. That friend agreed, and then snitched on her to the mental health authorities. They treated her for depression and found a doctor to do a hip replacement. She later said that she was very glad her friend had ratted her out, and that she hadn't died. She said that suicide seemed like a rational choice, but that her pain and depression had kept her from seeing other options. She lived many more happy years. Another friend had a son who suffered from schizophrenia. He had been treated for it without success, and had been hospitalized many times. He finally committed suicide, leaving a note saying that he just didn't want to live like that anymore. Was that a rational decision? Was he even capable of making a rational decision? Darned if I know. I do think it is possible for suicide to be a rational decision in some (very narrow) circumstances, for some people. Unfortunately, I don't think people are always able to judge whether they're being rational, especially if they're depressed. I certainly don't feel qualified to make that judgement about someone else.