Antidepressants are a type of medication used to treat several mental health conditions. They are a type of medicine that are used by millions worldwide.

They are commonly used for conditions like Depression and Anxiety. There are several classes of Antidepressants, as will be discussed.

Antidepressants have helped many people overcome mental health problems.

A range of antidepressants exist

Information on Antidepressants

It normally takes between four and six weeks for an antidepressant’s full effectiveness to be felt. However, minor improvements may be visible after around a week.

It is important to take an antidepressant how and when a Doctor has advised. This involves taking the correct dose at the right time, and taking the medication on a consistent basis. Never take more than one dose at a time to make up for a forgotten dose.

A low dose will initially be prescribed. Once remission has been achieved, it is important to continue to take an antidepressant, as this will improve the chances of symptoms not coming back. Sometimes, antidepressant use can last for lifetime.

What conditions are Antidepressants used for?

Antidepressants can be used in the treatment of a wide array of conditions, such as:

  • Depression
  • Anxiety
  • Post-Traumatic Stress Disorder
  • Adjustment Disorder
  • Obsessive-Compulsive Disorder
  • Personality Disorders
  • Dissociative Disorders
  • Eating Disorders
  • Somatic Disorders

What are the different types of Antidepressants?

There are over 20 antidepressants licensed for use in the United Kingdom. Others exist, but not all are licensed for use in the United Kingdom.

There are five categories of antidepressants. Within these five categories are a range of antidepressants.

  • Selective Serotonin Reuptake Inhibitors (SSRIs): These are the most widely prescribed and best-known class of antidepressants. They cause fewer side effects than others, and overdose toxicity is low. They appear to work by increasing the level of the chemical serotonin in the brain.
    • Fluoxetine (Prozac)
    • Citalopram (Cipramil)
    • Sertraline (Zoloft)
    • Paroxetine (Paxil)
    • Escitalopram (Cipralex)
    • Fluvoxamine (Faverin)
    • Vortioxetine (Brintellix)
  • Serotonin Norepinephrine Reuptake Inhibitors (SNRIs): This class is very similar to SSRIs. They were created later than SSRIs. They also have few side effects and overdose toxicity is low. SNRIs target both serotonin and norepinephrine. While a range of SNRIs exist, only two are prescribed in the UK:
    • Duloxetine (Cymbalta)
    • Venlafaxine (Efexor)
  • Tricyclic Antidepressants (TCAs): These are some of the oldest antidepressants – with many of these having been developed in the 1950s. They have more unpleasant side effects compared to SSRIs and SNRIs, and an increased risk in overdose. They are sometimes prescribed when a patient doesn’t respond to antidepressants from other classes.
    • Amitriptyline (Elavil)
    • Clomipramine (Anafranil)
    • Imipramine (Tofranil)
    • Lofepramine (Gamanil)
    • Dosulepin (Prothiaden)
    • Doxepin (Sinequan)
    • Nortriptyline (Pamelor)
    • Trimipramine (Surmontil)
  • Monoamine Oxidase Inhibitors (MAOIs): If all other classes of antidepressants have not worked, MAOIs are generally the last line of medication that is tried. These are very old medicines that require dietary restrictions for those who take them. It is very rare that an MAOI is prescribed.
    • Isocarboxazid (Marplan)
    • Moclobemide (Manerix)
    • Tranylcypromine (Parnate)
    • Phenelzine (Nardelzine)
  • Atypical Antidepressants: This class of antidepressants have a unique action to other antidepressants. These medicines work on various chemicals. They are normally used as an add-on medication to other antidepressants, but can be prescribed on their own.
    • Mirtazapine (Remeron)
    • Trazodone (Molipaxin)
    • Agomelatine (Valdoxan)
    • Mianserin (Tolvon)
    • Reboxetine (Edronax)

It is important to mention that there are a range of other medicines that have antidepressant-like qualities to them. Moreover, there are many other antidepressants that exist, but are not licensed in the United Kingdom.

How do Antidepressants work?

It isn’t entirely known how antidepressants work. It is believed that antidepressants work by increasing levels of a group of chemicals in the brain called neurotransmitters.

Some of these neurotransmitters, such as serotonin, dopamine and norepinephrine, appear to be related to mood and emotion. How the exact process works isn’t known.

Side Effects of Antidepressants

Side effects are common with antidepressants. However, the side effects associated with each medicine differs from medication to medication. With any antidepressant, a Patient Information Leaflet will be included in the box. This leaflet provides an exhaustive list of side effects.

Side effects from antidepressants are normally rather mild, and should only last for a few days as the body gets used to the medication. Some side effects, such as dry mouth or increased appetite, may be persistent.

Common side effects of antidepressants include sexual dysfunction, headaches, sickness, drowsiness, increased/decreased appetite, dry mouth, constipation, weight gain, excessive sweating, dizziness and sedation.

Serious side effects include suicidal thoughts, seizures, chest pain, psychosis or any abnormal behaviour. An overdose should be avoided, as it can cause the potentially fatal Serotonin Syndrome. If any of the side effects in this area appear, it is important to contact a Doctor or emergency department immediately. 

If side effects from antidepressants persist for a few weeks, or provide discomfort, it may be worth switching medication to an alternative antidepressant – although this should be done in conjunction with a Doctor.

Cautions of Antidepressants

It is important to thoroughly read the Patient Information Leaflet that comes with your medication. The leaflet will include specific cautions that should be taken into consideration when taking an antidepressant.

General considerations when taking antidepressants include:

  • Tell a Doctor about any medicine or substance that is currently being used – such as Herbal Remedies like St. John’s Wort
  • Avoiding alcohol in the first few days of treatment, to allow the body to get used to the medication. After adjustment is complete, it is advised to not consume alcohol – given its properties as a depressant. If consumed, drinking alcohol in moderation is important.
  • Any antidepressant can react unpredictably with illegal drugs; therefore it is advisable to not use recreational drugs when undergoing antidepressant therapy.
  • Studies show that people under the age of 25 taking antidepressants are at heightened risk of suicidal ideation [1]. Therefore, it is important to exert caution during treatment.
  • Antidepressants shouldn’t routinely be taken during pregnancy or breastfeeding. It is important to discuss this with a Doctor.
  • To remember that antidepressants are most effective when combined with a form of talking therapy. Antidepressants can help relieve symptoms, but not cure a mental health condition.


Antidepressants are a widely-used medicine. They can play a role in the treatment of many mental health conditions.

It is important to take care when taking any medicine. But when used properly, antidepressants generally provide benefits to patients.

See Also

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[1] Leslie, L. K., Newman, T. B., Chesney, P. J., & Perrin, J. M. (2006). The Food and Drug Administration’s Deliberations on Antidepressant Use in Pediatric Patients. Pediatrics. 116 (1): p195-204. DOI: