Severe depression, or major depressive disorder, is a disabling mood disorder characterized by feelings of sadness, hopelessness and loss of interest in daily activities. Antidepressant medications and counseling, or psychotherapy, are the most common treatment methods. Antidepressants work by modifying the relative activity of different neurotransmitters in the brain. These medications are grouped into categories based on the method of action, and drugs in each group have similar properties and side-effect profiles.
Types
According to their method of action, antidepressants can be categorized as monoamine oxidase inhibitors, or MAOIs; tricyclic antidepressants, or TCAs; selective serotonin reuptake inhibitors, or SSRIs; and serotonin norepinephrine reuptake inhibitors, or SNRIs. Drugs from any group may be used to treat severe depression; the choice depends on which seem to work best for the patient and have the fewest side effects.
History
The first antidepressant drugs were the MAOIs. The very first drug, iproniazide, was discovered by accident when researchers were trying to find new anti-tuberculosis drugs. In the 1950s, TCAs were discovered to have antidepressant effects and became the standard of pharmacological care. According to an article on the website of the University of Arkansas for Medical Science, newer drugs were sought for treatment of depression due to the troublesome side-effect profile of TCAs. The search resulted in SSRIs and SNRIs.
Effects
As their name implies, the effect of antidepressant medications is to elevate mood in patients diagnosed with moderate to severe depression. Some drugs in this class are also used in treatment of anxiety disorder; childhood enuresis, or bed-wetting; diabetic neuropathy pain; and post-traumatic stress disorder, or PTSD.
Warnings
Each category of drugs has accompanying side effects and warnings.
Side effects from SSRIs are infrequent and may include sensitivity to sunlight, weight loss and sexual dysfunction. The website FamilyDoctor.org states that because of the low incidence of side effects, SSRIs are the most commonly prescribed medications for severe depression. However, women who are pregnant or may become pregnant should not take SSRIs due to possible injury to the unborn child.
Side effects are common for individuals taking TCAs. These side effects may include dizziness, dry mouth, impaired concentration, nausea, nervousness and decreased libido. An article on the Mayo Clinic website notes that due to the frequency of these side effects, TCAs are generally not the first choice for treatment of severe depression.
Tyramine, an amino acid found in various foods, can cause a serious reaction in patients taking MAOIs. In certain individuals, this reaction can trigger a potentially fatal hypertensive crisis. This is the reason that many doctors prescribe MAOIs only for individuals who do not respond to other antidepressant medications. Aside from its reaction with tyramine, the side effect profile of MAOIs is similar to that of TCAs.
Expert Insight
Many health care professionals believe that antidepressants are overprescribed these days. As a physician, it is important to evaluate the patient before prescribing any medication, especially one that affects mood. There are several lifestyle changes, including regular exercise, diet and psychological counseling that can drastically improve mood. If an individual is so severely depressed that he cannot function, then a brief course of antidepressants may be the best way to get him into a state where he can make the lifestyle changes necessary for long-term stability. However, it is unwise to blindly prescribe these powerful medications as a quick-fix to everyone suffering from the blues.
