Text adapted from "The patient who is depressed" in Psychiatry in primary care by Raymond W. Lam,  (CAMH, 2019).

Acute Treatment

The goals for acute treatment of depression are full symptom remission and return to baseline functioning. Among patients undergoing primary care treatment for depression, 60 to 80 per cent achieve symptom remission. Remission typically is defined as having normal mood and minimal symptoms, but it is best evaluated using a rating scale (e.g., a score within the normal range on the PHQ-9, Hamilton Depression Rating Scale or Beck Depression Inventory).

Antidepressant medications are the first-choice treatment for moderate to severe depression. (For treatment of mild to moderate depression, see “Psychotherapy.”) The newer antidepressants—selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), bupropion, mirtazapine and vortioxetine—are all first- line medications, offering improved tolerability and a better safety profile compared with tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs) (Bezchlibnyk-Butler et al., 2014; Stahl, 2017). The following tables summarize antidepressant characteristics.
  

Choosing an antidepressant

Usually there is not one definite choice of antidepressant for any given patient because there is so much individual variability in efficacy and side- effects. The choice is based primarily on individual profiles of efficacy, tolerability and anxiety indications. See Table 1 for guidance, and also consider these findings:

• There is some evidence for slightly increased efficacy with escitalopram, mirtazapine, sertraline and venlafaxine, particularly in patients with more severe depression.
• There is some evidence for better short-term tolerability with bupropi-  on, citalopram, desvenlafaxine, escitalopram and sertraline. Bupropion, desvenlafaxine, mirtazapine, vilazodone and vortioxetine have fewer sexual side-effects than other antidepressants.
• A broad-spectrum medication (indicated for both depressive and anxiety disorders) is recommended due to high comorbidity of these disorders.
• Efficacy for most anxiety disorders is demonstrated with escitalopram, paroxetine, sertraline and venlafaxine. Other antidepressants also may be effective for anxiety disorders, but they have not been studied.
• Cognitive dysfunction is commonly seen in depression. There is some evidence that vortioxetine improves depression-associated cognitive dysfunction.