Antidepressants are a variety of medications used in the treatment of depression and other mental health conditions and are one of the most commonly prescribed medications around. Antidepressants were first developed in the 1950s. Their use has become progressively more common in the last 20 years. According to the Centers for Disease Control and Prevention (CDC), around twice as many females use antidepressants as males.

It is believed that the aim of antidepressant medications is to change chemicals (neurotransmitters) in the brain that affect mood and emotions. When someone suffers from the pain and anguish of depression, that can sound like a simple and convenient method of relief. However, it is important to note that depression isn’t simply caused by the imbalance of
the chemicals in the brain. It is caused by a complex combination of biological, psychological, and social factors, which includes lifestyle, relationships, and coping skills that medication can’t address.

It’s not known exactly how antidepressants work.

It is known that certain neurotransmitters, such as serotonin and noradrenaline, are linked to mood and emotion. Neurotransmitters may also affect pain signals sent by nerves, therefore some antidepressants can help relieve long-term pain. Even though antidepressants may treat the symptoms of depression, they do not always address its causes. This is why they’re usually used in combination with therapy to treat more severe depression or other mental health conditions.

Antidepressants are divided into five main types:

SNRIs and SSRIs – are the most commonly prescribed type of antidepressant.

Serotonin and noradrenaline reuptake inhibitors (SNRIs) raise levels of serotonin and norepinephrine, two neurotransmitters in the brain that play a key role in stabilizing mood. SNRIs are used to treat major depression, mood disorders, and possibly but less commonly attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), anxiety disorders, menopausal symptoms, fibromyalgia, and chronic neuropathic pain. SNRIs include duloxetine (Cymbalta), venlafaxine (Effexor), and desvenlafaxine ( Pristiq ).

Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressants. It is believed that they are effective in treating depression, and they have fewer side effects than the other antidepressants. SSRIs block the reuptake, or absorption, of serotonin in the brain. This makes it easier for the brain cells to receive and send messages, resulting in better and more stable moods. SSRIs include citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem), fluvoxamine (Luvox), paroxetine (Paxil) and sertraline (Zoloft).

Tricyclic antidepressants (TCAs)
There are three rings in the chemical structure of these medications that why they are called Tricyclic antidepressants (TCAs). They are used to treat depression, fibromyalgia, some types of anxiety, and they can help control chronic pain. TCAs include amitriptyline (Elavil), amoxapine- clomipramine (Anafranil), desipramine (Norpramin), doxepin (Sinequan), imipramine (Tofranil), nortriptyline (Pamelor), protriptyline (Vivactil) and trimipramine (Surmontil).

Monoamine oxidase inhibitors (MAOIs)
Before the introduction of SSRIs and SNRIs, this type of antidepressant was commonly prescribed. It inhibits the action of monoamine oxidase, a brain enzyme. Monoamine oxidase helps break down neurotransmitters, such as serotonin. If less serotonin is broken down, there will be more circulating serotonin. In theory, this leads to more stabilized moods and less anxiety. MAOIs include phenelzine (Nardil), tranylcypromine (Parnate), isocarboxazid (Marplan), and selegiline (EMSAM, Eldepryl).

Noradrenaline and specific serotoninergic antidepressants (NASSAs)
These are used to treat anxiety disorders, some personality disorders, and depression.
NASSAs include Mianserin (Tolvon) and Mirtazapine (Remeron, Avanza, Zispin).

It is important to note that every antidepressant medication has its side effects. According to NICE (2009), all patients should be informed that, although the drugs are not associated with tolerance and carving, withdrawal symptoms may occur on stopping or missing doses. The research shows that clear communication with patients has often been lacking. It was found that a significant disparity in the content, quality, and usefulness of information leaflets inserted into packets of antidepressants. Leaflets did not warn about discontinuation syndromes, side effects were listed inconsistently and almost half of the leaflets did not warn against using St John’s Wort during treatment. Up to 40% of patients taking SSRIs do not attain relief from their depression, where relief is defined as a 50% reduction in depressive symptomatology following 6-8 weeks of therapy.

Common side effects of SSRIs and SNRIs include:

  • feeling and being sick
  • feeling agitated, shaky or anxious
  • headaches
  • not sleeping well (insomnia), or feeling very sleepy
  • diarrhea or constipation
  • low sex drive
  • indigestion and stomach aches
  • dizziness
  • loss of appetite
  • difficulties achieving orgasm during sex or masturbation
  • in men, difficulties obtaining or maintaining an erection (erectile dysfunction)

There have been reports that people who use SSRIs and SNRIs, and especially those under the age of 18 years, may experience thoughts of suicide, especially when they first start using the drugs.

Common side effects Tricyclic antidepressants (TCAs) include:

  • dry mouth
  • slight blurring of vision
  • dizziness
  • constipation
  • drowsiness
  • weight gain
  • problems passing urine
  • excessive sweating – especially at night
  • heart rhythm problems, such as noticeable palpitations or a fast heartbeat (tachycardia)

High Health Risks:

Serotonin syndrome is a rare but serious set of side effects with SSRIs and SNRIs. It happens when the levels of a chemical in the brain (serotonin) become too high. When SSRI or SNRI is taken with another substance that raises serotonin levels eg. an antidepressant or St John’s Wort, it can then cause the serotonin syndrome.

Hyponatremia – An elderly person who takes antidepressants, may notice a severe fall in sodium (salt) levels. This is hyponatremia. This may lead to a build-up of fluid inside the cells of the body, which can be dangerous. SSRIs can block the effects of a hormone that regulates levels of sodium and fluid in the body. Fluid levels become more difficult for the body to regulate as people age.

Diabetes – Long-term use of SSRIs and TCAs have been linked to an increased risk of developing type 2 diabetes. But it’s not clear if the use of these causes diabetes to develop directly. Some people gain weight when using antidepressants. This may increase the risk of developing type 2 diabetes.

Suicidal thoughts – There is a danger that, in some people, antidepressant treatment will cause an increase, rather than a decrease, in depression. Young people under 25 years old seem, particularly at risk. The suicide risk is particularly great during the first month or two of treatment. Anyone taking antidepressants should be closely watched for suicidal thoughts and behaviors. Monitoring is especially important if this is the person’s first time on depression medication or if the dose has recently been changed.

Medication isn’t the only option for depression relief


It’s important to remember that antidepressants aren’t a cure. Medication may treat some symptoms of depression, but can’t change the underlying issues and situations in someone’s life that is making them depressed. Exercise, therapy, mindfulness meditation, social support, and another lifestyle should be taken into consideration. These non-drug treatments can produce lasting changes and long-term relief.

Some people who respond initially to medication can slip back into depression, as can those who stop taking the medication. Antidepressants often come with unpleasant side effects so it’s important to weigh the benefits against the risks when considering depression medication.

Many people with mild to moderate depression find that therapy, exercise, and self-help strategies work just as well or even better than medication—minus the side effects.

Antidepressant withdrawal:

Once someone started to take antidepressants, it can be tough to stop. Many people have severe withdrawal symptoms that make it difficult to get off of the medication. Which is another reason not to stay on any medication longer than necessary. The withdrawal symptoms include:

  • Anxiety, agitation
  • Depression, mood swings
  • Nausea and vomiting
  • Insomnia, nightmares
  • Irritability and aggression
  • Flu-like symptoms
  • Extreme restlessness
  • Fatigue
  • Dizziness, loss of coordination
  • Electric shock sensations
  • Tremor, muscle spasms
  • Stomach cramping and pain

There are few tips for stopping an antidepressant safely, it includes:

Reduce the dose gradually.
Don’t rush the process.

Choose a time to stop that isn’t too stressful.

Antidepressants are frequently prescribed treatments for depression. Their effectiveness is not clearly established for patients with mild to moderate depression. However, for patients with more severe depression, it appears to be evidence of positive treatment effects. Treatment adherence is complex by differential side effect profiles and problems with treatment.

Carr, A., & McNulty, M. (Eds.). (2006). The handbook of adult clinical psychology. London: Routledge.

Harmer, C.J., Goodwin, G.M., & Cowen, P.J. (2009). Why do antidepressants take so long to work? A
cognitive neuropsychological model of antidepressant drug action. British Journal of Psychiatry, 195(2), 102-108.

Harmer, C.J. Shelly, N.C., Cowen, P.J. & Goodwin, G.M. (2004). Increase positive versus negative affective perception and memory in healthy volunteers following selective serotonin and norepinephrine reuptake inhibition. American Journal of Psychiatry, 161(7), 1256-1263.

National Institute of Health and Clinical Excellence (2009). Depression: The treatment and management of depression in adults CG90. London: Author.

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