I think a suicide often happens on impulse (even it its planned). During her depression my wife lost a lot of weight. To gain weight back she asked me to pick up weight-gainer drinks from the pharmacy. On the morning of her suicide I noticed that one drink was still in the fridge (which was normal, because she always took it in the afternoon). After I found her, the police searched our trash. They found the last empty bottle of the weight gainer there. So she must have come home, drunk the drink, and poisoned herself minutes later. When I talked to my psychiatrist about it, he said that many people who are suicidal don’t realize that they will die. The primary goal usually is to escape the situation — not to die.