Depending on the severity and pattern of depressive episodes over time, health-care providers may offer psychological treatments such as behavioural activation, cognitive behavioural therapy and interpersonal psychotherapy, and/or antidepressant medication such as selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs). Different medications are used for bipolar disorder. Health-care providers should keep in mind the possible adverse effects associated with antidepressant medication, the ability to deliver either intervention (in terms of expertise, and/or treatment availability), and individual preferences. Different psychological treatment formats for consideration include individual and/or group face-to-face psychological treatments delivered by professionals and supervised lay therapists. Antidepressants are not the first line of treatment for mild depression. They should not be used for treating depression in children and are not the first line of treatment in adolescents, among whom they should be used with extra caution.