How do you know if you're just feeling a bit sad or if you are depressed? What level of sadness is 'normal'? How do you work out what's going on when you feel down? What kinds of treatment are available? How do you help a family member or friend who is depressed? Psychologist Gwendoline Smith answers these questions and many more. She specifically addresses postnatal blues and depression; depression in children, teens and older people; and depression in relation to gender and sexuality.