To give the reader some context in order to grasp the significance of the issue of a possible new class of antidepressant medications, I would offer the following points of information.
First, in spite of 30 years of hype and advertising by the pharmaceutical industry and especially the companies who have one by one introduced and advertised the so-called modern, or serotonin-based antidepressants, not much progress has been made in the actual efficacy of treating major depressive disorders with these medications. When the serotonin-based antidepressant medications started to emerge in the marketplace, the armamentarium of the psychiatrist and family physician, in the realm of novel pharmaceutical based advertising on Western television, the mode of action on a supposedly new neurotransmitter system was greatly hailed as a modern breakthrough. Serotonin actually is been known since the 1950s and the neuroscience circles in general.
Second, the only advance that was basically made was a reduction in the anticholinergic side effects of the previous generation of antidepressant medications. These the side effects are largely antihistamine. This means that they make nearly all mucous membranes and dry. This accounts for their marketed value in treating and controlling the symptoms of runny noses and watery eyes of viral colds and pollen allergies. These side effects present in the antihistamine medications and “try cyclic” antidepressant medications also cause decreased propulsion in the gastrointestinal tract, meaning the longer transit time for food and waste material through the small and large intestines. The longer that the foodstuffs and wastes stay especially in the large intestine, the more time there is for reabsorption of water from the stool. This makes for hard stool and consequently the long known constipation with all these medications. These same anticholinergic side effects can also affect heart rate and decrease blood pressure. The latter side effect is very problematic in the elderly and can cause lowered blood pressure upon standing and consequently falls in the elderly with alarming frequency and subsequent injuries such as hip fractures.