Help! Someone I Love has a Mental Illness

Depression, bipolar disorder, anxiety disorder, post-traumatic stress disorder, personality disorder, OCD, ADHD and so on. These words strike fear into the hearts of mothers, fathers and partners. When you first suspect that your loved one is sick, it can be confusing and frightening, for them and also for you. You question yourself and them - is it real, how do I help, what does this mean, can't you get over it, did I do something wrong?