NICE (National Institute for Health and Care Excellence), SIGN (Scottish Intercollegiate Guidelines Network) and BAP (British Association for Psychopharmacology) all offer guidelines on treating depression. All bodies recommend that the initial treatment for moderate to severe depression should include a trial of an antidepressant. For mild depression, NICE recommends a physiological or 'talking' therapy known as cognitive behavioural therapy (CBT).

In practice, access to CBT is difficult and waiting lists can be up to one year long. Therefore, prescribers may offer antidepressants to mildly depressed patients despite it not being in line with guidelines. There are various groups of antidepressants, the most commonly used being selective serotonin re-uptake inhibitors (SSRIs). In some cases when an SSRI has already been tried, venlafaxine or mirtazapine will be offered.

The older groups of drugs, known as the monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants (TCAs), are not routinely offered due to their low tolerance and potential side effects. Amitriptyline may be dispensed in the pharmacy unless the dose is 200mg or above. Such doses are for another disorder (e.g. neuropathic pain).