How long should we wait before we decide whether or not a person has developed a clinical depression during his or her life? Suppose, for example, that an individual with a strong family history of depression dies in an auto accident at the age of twenty-one without ever having had an episode of clinical depression. We might conclude that she or he did not inherit the tendency for depression. But if that individual had not died, she or he might have developed an episode of depression later on in life, since a first episode of depression can often occur when you are older than twenty-one.