What are Antidepressants?
- Drugs that are used primarily to elevate mood and relieve depression (Butcher, Mineka & Hooley, 2004)
- Drugs that regulate mood (Santrock, 2003)
An Overview on Antidepressants
Antidepressants work by influencing the uptake systems of the neurotransmitters serotonin and norepinephrine. Some examples of antidepressants include the tricyclics, monoamine oxidase inhibitors (MAOs), selective serotonin re-uptake inhibitors (SSRIs) and serotonin and norepinephrine re-uptake inhibitors (SNRIs). Early antidepressants, like the tricyclics and the MAOs have already been replaced by the SSRIs and the SNRIs because of their severe negative side effects. However, SSRIs and SNRIs also not necessarily better than the tricyclics and the MAOs.
Antidepressants for Anxiety Disorders
Antidepressants, especially the selective serotonin re-uptake inhibitors (SSRIs), are useful not just in treating depression, but also in treating anxiety disorders such as panic disorder, social phobia, generalized anxiety disorder, and obsessive-compulsive disorder. However, because of the severe side effects of SSRIs, some panic disordered patients immediately stop using them because the side effects may trigger hypersensitivity and thus more cases of panic attacks occurring during the first few weeks of treatment. Despite this ugly immediate effect of SSRIs in panic disorder, it remains to be a very effective drug in treating the disorder.
Antidepressants for Depression in Coronary Heart Disease
Depression is a major risk factor for heart attacks in coronary heart disease, that is why it is very important that cardiac patients must be treated for their depression as well. Tricyclic antidepressants are the most effective when it comes to treating unipolar mood disorders, let alone their main symptom, which is depression. However, tricyclic antidepressants are contraindicated to patients with coronary heart disease. It is in this scenario that selective serotonin re-uptake inhibitors (SSRIs) are the main players in reducing depressive symptoms in cardiac patients. Although SSRIs are less effective than tricyclics in treating depression in unipolar mood disorders, studies show that it is effective in treating depression in coronary heart disease.
Introduction to Antidepressants
Antidepressants work by increasing the supply of serotonin, norepinephrine, or both, in the synapse. Most do this by inhibiting the re-uptake of these neurotransmitters upon release from the neurons.
There are five classes of antidepressants - monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), selective serotonin re-uptake inhibitors (SSRIs), serotonin and norepinephrine re-uptake inhibitors (SNRIs), and the atypical antidepressants.
MAOIs inhibit the activity of the monoamine oxidase enzyme. The MAO enzyme, which is located at the synpatic cleft, breaks down monoamine neurotransmitters, such as serotonin and norepinephrine. If the MAO enzyme is inhibited, the level of serotonin and norepinephrine in the synapse increases. As a result, patients feel "happier." Patients, however, should avoid eating salami and Stilton cheese, as these foods are rich in the amino acid tyramine, which limits the effect of the drug. Although MAOIs are rarely used today, they remain to be the chosen drug for atypical depression characterized with hypersomnia and overeating, as patients with this kind of depression often do not respond well to other classes of antidepressants.
TCAs inhibit the re-uptake of norepinephrine and serotonin (although to a lesser extent), thus increasing the levels of norepinephrine and serotonin in the synapse. TCAs accomplish this not only by blocking the re-uptake of these neurotransmitters, but also by reducing the activity of the receptors and affecting the process in which neurons synthesize the neurotransmitters and respond to their activation. For example, picture the process as a volleyball game. The ball is the neurotransmitter serotonin/norepinephrine and the opposing team members are the presynaptic and postsynaptic neurons. TCAs ensure that the ball will stay on air by blocking it with a net, so that the opposing team will not hold it. If the ball get past the net, TCAs try to blur the vision of the opponent team so that they won't even touch it. If an opponent member was able to touch the ball despite a bad vision, TCAs will force the opposing team member to hit it back rather than hold it.
SSRIs selectively inhibit only the re-uptake of serotonin (and not norepinephrine), thus increasing its supply in the synapse. The side effects of SSRIs (such as nausea, diarrhea, nervousness, insomnia, diminished sexual interest and orgasmic problems), although are still quite uncomfortable, are not as severe and not as many as those found in the use of MAOIs and TCAs. Consequently, among the classes of antidepressants, SSRIs are the most widely used. However, the relative "safeness" associated with this class does not guarantee effectiveness, especially for patients with serious problems, like having major depressive disorder. Dysthymics, however, generally benefit from this class.
SNRIs inhibit the re-uptake of both serotonin and norepinephrine. They are also considered relatively safe because the side effects associated with their use resemble those in SSRIs. SNRIs are also shown to be more effective than SSRIs in treating patients with major depressive disorder.
Atypical antidepressants are named so because the way they function cannot be simply classified into a single class. Atypical antidepressants include nefazodone, trazodone, bupropion, and mitrazapine. Nefazodone inhibits the re-uptake of both serotonin and norepinephrine, and also affects the synthesis of serotonin. Unlike SSRIs, it does not inhibit sexuality and does not cause insomnia. However, it requires strict monitoring because misuse of the drug may lead to liver damage. Trazodone is structurally related to nefazodone, but it only inhibits the re-uptake of serotonin. It is often prescribed alongside SSRIs to counter insomnia because of its sedative effects. Compared to nefazodone, it is relatively safe even if taken in overdose. Buproprion does not block the re-uptake of any neurotransmitter; rather, they increase noradrenegic activity through mechanisms that are not yet clearly understood. Like nefazodone, buproprion does not inhibit sexual activity. Mitrazapine, lastly, is the most recently introduced antidepressant drug. It blocks the re-uptake of both serotonin and norepinephrine. The only side effect with the use of this drug is weight gain.
Antidepressants, as the name implies, are mainly used to treat depression. However, research shows that these drugs are also useful in treating other problems, such as anxiety disorders, eating disorders, and personality disorders. In fact, about two-thirds of patients with body dysmorphic disorder significantly benefit from SSRIs.
Frequently Asked Questions
- What does 50% improvement means?
- Do these drugs work in contrast with antianxiety agents?
- How do antidepressant drugs regulate mood?
- How do these drugs affect the movement and levels of certain neurotransmitters in the brain?
- Can these drugs be prescribed for childhood depression?
- How do these drugs affect people with cognitive disorders?
- How do these drugs affect people with depressive disorders?
- Can these drugs also treat panic and anxiety disorders? If so, how can it do so when it elevates mood, and may therefore increase anxious behaviors?
- Do antidepressant drugs increase or reduce the intensity of phobic reactions?
- Can these drugs reduce the symptoms of posttraumatic stress disorder?
- How do these drugs affect people with somatoform disorders?
- How do antidepressants work?
- Can antidepressants be administered in pregnant women?
- Can they reduce the risk for the development of anorexia nervosa? Can they also treat it?
- Do people with antisocial and psychopathic personality benefit from the effects of antidepressants?
- How can antidepressants treat anxiety disorders?
- Can they also treat body dysmorphic disorder? In what way?
- How about bulimia nervosa?
- Are they also prescribed for cataplexy?
- Is the effect different when these drugs are administered to treat depression in children compared to adults?
- How do people with cluster A personality disorders react when these are administered to them?
- How about people with cluster B personality disorders? Do they react the same way?
- Can they reduce the risk for coronary heart disease if such was caused by depression?
- Can people with generalized anxiety disorder benefit from using them?
- Can they cure major depression? Or do they only reduce the severity?
- How do antidepressants regulate and control mood disorders?
- Can they be administered to people with obsessive-compulsive disorder?
- How can these drugs treat post-traumatic stress disorder?
- Can they also prevent premature ejaculation? How?
- Do antidepressants work the same way with social phobia as they do with other common phobias?
- Can they treat somatoform pain disorders?
- How about stress disorder?
- Do the effects of antidepressants increase or decrease when administered along with electroconvulsive therapy?
- Are they more effective if followed up with psychotherapy?
- What are the commonly prescribed antidepressants?
- How about those that are commonly used?
- What is the course of treatment?
- Do antidepressants increase or decrease the levels of dopamine in the brain?
- What are heterocyclic antidepressants?
- Are monoamine oxidase inhibitors classed as antidepressants?
- Do antidepressants increase or decrease the levels of norepinephrine in the brain?
- Are selective serotonin reuptake inhibitors classed as antidepressants?
- What are the side effects of these drugs?
- What are tricyclic antidepressants?
- How do tricyclics differ from other types of antidepressant drugs?