antidepressants

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Introduction

Antidepressants are medications used in the treatment of depression, but many can also be used in conditions such as anxiety disorders and obsessive compulsive disorder. Most antidepressants are taken orally.

What we already know

Antidepressants can be divided into six groups, based on their mechanism of action:

  1. Selective Serotonin Reuptake Inhibitors (SSRIs)“ e.g. Citalopram, Sertraline
  2. Serotonin-Noradrenaline Reuptake Inhibitors (SNRIs)“ e.g. Venlafaxine, Duloxetine
  3. Noradrenergic and Specific Serotonergic Antidepressants (NaSSAs) e.g. Mirtazapine
  4. Tricyclic Antidepressants (TCAs)“ e.g. Amitriptyline, Imipramine
  5. Monoamine Oxidase Inhibitors (MAO-Is) e.g. Phenelzine, Moclobemide
  6. Miscellaneous“ e.g. Bupropion, Trazodone, Reboxetine

Side effects depend on the mechanism of action and can vary from person to person.

NICE guidelines suggest use of antidepressants in moderate or severe cases of depression only. The risks of antidepressant medication use in mild depression outweigh the benefits, so other forms of therapy (e.g. CBT) are recommended in these cases.

Areas of uncertainty

  • The exact mechanisms of action – we are yet to find out exactly why and how many of the antidepressants work (there are inconsistencies in the monoamine theory of depression)
  • How to limit side effects associated with antidepressant use
  • How many people experience withdrawal effects and how best to withdraw from antidepressants
  • Using antidepressants in special groups – limited data exists for which antidepressants (if any) are best to use in pregnant women, children and the elderly

What’s in the pipeline

  • Ketamine has been shown to have promising antidepressant effects, although further randomised placebo-controlled trials are needed (Coyle and Laws, 2015)
  • Research is ongoing into the biological causes of depression and it is hoped that when this is better understood, therapy can be targeted towards the exact cause
  • Further research is also being conducted into the long term effects of antidepressants
  • Research aimed at developing more personalised treatment for depression is also underway

References

NICE guidelines CG90 (2009) ‘Depression in adults: The treatment and management of depression in adults’ [PDF]

Semple, D. and Smyth, R. (eds.) (2013) Oxford Handbook of Psychiatry. 3rd ed. Oxford: Oxford University Press. (Publisher)

Coyle, C. M. and Laws, K. R. (2015), ‘The use of ketamine as an antidepressant: a systematic review and meta-analysis.’ Hum. Psychopharmacol Clin Exp, doi: 10.1002/hup.2475 [Abstract]

Acknowledgement

Written by: Josephine Neale
Reviewed by: Helge Hasselmann
Last updated: Jun 2019
Review due: Jun 2020

Our antidepressants Blogs

Are antidepressants safe? A new umbrella review of observational studies suggests they are, but we need more accurate data

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Andrea Cipriani and Anneka Tomlinson scrutinise a brand new umbrella review of the associations between antidepressants and adverse health outcomes, which suggests that antidepressants are safe for most people who experience mental health difficulties.

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In adults with major depression, antidepressants may increase the risk of suicide

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Douglas Badenoch explores a meta-analysis of follow-up data from clinical trials of antidepressants, which found a small but significant increase in suicide risk.

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Intranasal esketamine for treatment-resistant depression: the first clinical study

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Jodi Rintelman writes her debut elf blog on the first randomised controlled trial on the efficacy and safety of intranasal esketamine as an adjunctive treatment to antidepressants for treatment-resistant depression.

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Higher doses of antidepressants “not optimal”, according to new review

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Jonathon Tomlinson considers his options as a GP supporting people with depression and complex needs, after reading a new systematic review and dose-response meta-analysis, which suggests that higher doses of antidepressants bring maximum side effects with only marginal gains.

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Antidepressants and weight gain: long-term population impact #SUSANAsurvey

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Andrea Cipriani and Anneka Tomlinson summarise a 10-year cohort study of antidepressant use and incidence of weight gain.

They also launch their new SUSANA project: Survey for Understanding Side effects of ANtidepressants in Adults. Please take the SUSANA survey now!

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Antidepressant withdrawal: slower and lower tapering of SSRIs

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A group of UCL Masters Students summarise a recent personal view by Mark Horowitz and David Taylor about tapering of SSRI treatment to mitigate antidepressant withdrawal symptoms.

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Pregnancy and bipolar disorder: international prescribing consensus?

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Dean Connolly looks at an international study which asks: Is there consensus across evidence-based guidelines for the psychotropic drug management of bipolar disorder during the perinatal period?

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Improving antidepressant outcomes: what works for whom and why?

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Thalia Eley and Gerome Breen explore a new systematic meta-review of predictors of antidepressant treatment outcome in depression, which looks at clinical and demographic variables, but also biomarkers including both genetic and neuroimaging data.

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Antidepressant withdrawal: reviewing the paper behind the headlines

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Joseph Hayes and Sameer Jauhar set the record straight on antidepressant withdrawal. They show how the recent review by Davies and Read is seriously flawed and does not accurately portray the data. They conclude that we urgently need clearer evidence on the incidence, severity and duration of any symptoms related to antidepressant withdrawal.

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Preventive cognitive therapy when continuing or tapering off antidepressants

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Linda Gask is encouraged by the findings of a new high quality RCT (the DRD study), which compares preventive cognitive therapy while tapering antidepressants versus maintenance antidepressant treatment versus their combination in the prevention of depressive relapse or recurrence.

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