Treatment for moderate-severe depressive disorder . As first-line therapy, health care providers may select psychological treatments (such as behavioural activation [BA], cognitive behavioural therapy [CBT], or interpersonal psychotherapy [IPT]) or antidepressant medication (such as selective serotonin reuptake inhibitors [SSRIs] and tricyclic antidepressants [TCAs]). They should keep in mind the possible adverse effects associated with antidepressant medications, the ability to deliver either intervention (in terms of expertise, and/or treatment availability), and individual preferences.