The term antidepressants refers to a group of medications that are useful in the treatment of major and minor depressive syndromes.
Here, we will try to clarify some basic concepts that may help explain the potential and limitations of this type of medication.
One important limitation is the name itself. “Antidepressant” is a term that suggests a treatment for “depression” without further qualification, but things are not quite that straightforward.
Almost all studies are conducted on depression as a syndrome rather than as a disease. Several neuropsychiatric disorders include depressive episodes over the course of the illness, or at its onset, but subsequently develop their own specific characteristics. In antidepressant studies, researchers attempt to isolate and study the effect of the antidepressant on the “depressive illness,” that is, single or recurrent episodes of depression. However, “single-episode” depression or recurrent depression are not necessarily stable diagnoses over time, because the emergence of subsequent features often justifies changing the diagnosis to a more specific disorder. Clinical trials do not usually allow enough time to establish this, because they typically end after a few weeks and therefore only establish what happens to that particular depression after 1–3 months of treatment.
The most typical development is that a single or recurrent depression becomes associated over time with features of activation or excitement, resulting in a shift toward a diagnosis within the bipolar spectrum, corresponding to a different model of illness.
Therefore, even antidepressant treatments that have been successful should nevertheless be reassessed after a certain period, in order to determine whether treatment needs to be “redirected” toward a different understanding of the disorder.
There is no such thing as a “better” or “stronger” antidepressant. Some appear to act more rapidly, but in general the effect of an antidepressant is assessed at the end of the first month, sometimes with a delay of a couple of weeks. There are different classes of antidepressants that work better or worse for different types of depression. Even among single-episode depressions, there are different “diseases” that respond to different neurochemical models.
People who experience periods of low mood usually try to identify the “main” symptom on which to base a label for themselves, in order to understand where to begin in solving the problem. Am I depressed or anxious? Am I more depressed or more anxious? Is anxiety causing my depression, or is it the other way around?
These questions are based on an incorrect assumption: that the symptom of “negative, low, melancholy mood” is itself depression. Depression, however, does not refer to the symptom itself, but to a collection of symptoms, that is, the “depressive syndrome,” meaning simply a “condition involving various symptoms, including depressed mood.” A depressive syndrome can itself correspond to several different types of illness, so it is not surprising that a friend or acquaintance who says they suffer from depression may receive completely different treatments or subsequently display completely different behaviors.
Anxiety is also typically present in “depressive syndromes,” so there is no contradiction or opposition between the two, nor do the symptoms necessarily cause one another. The two types of symptoms occur together so frequently that the term “anxious-depressive syndrome” is often used. This is a very provisional entity that may ultimately correspond to completely different disorders, or may constitute only one part of the clinical picture—the part that the patient identifies as the core of their suffering.