Most classes of antidepressant medications, including the selective serotonin reuptake inhibitors (SSRIs), are thought to require 2 or more weeks of use before therapeutic effects become noticeable. The consumer guidelines for a drug like Celexa (citalopram) clearly advise patients not to expect immediate benefits but to continue taking their medication as prescribed. However, a recent study has cast doubt on the notion that SSRIs really take weeks to build up to therapeutic levels. If the results are confirmed with subsequent experiments, then our understanding of these medications will be greatly enhanced. Observing the neurochemical mechanism behind specific SSRIs will naturally lead to more beneficial prescribing patterns and better patient outcomes.
In a study of the SSRI Celexa, 26 participants were given either a single dose of the drug or a dose of placebo, a harmless sugar pill. None of the participants had depression, a fact which allowed researchers to study specific physiologic responses without interference. Three hours later, participants were shown images of frightened faces while brain activity in their amygdala was measured via magnetic resonance imaging. Psychiatrists have theorized that hyperactivity in the amygdala is a measurable effect of depression that places the individual in a constant state of heightened anxiety. In the single-dose Celexa study, participants given medication showed a muted response in their amygdala when viewing frightened or anxious faces. Researchers observed a spike in amygdala activity in those who received placebo. These findings demonstrate that potentially therapeutic effects begin as quickly as a few hours after the first dose of Celexa, and by extension any SSRI. Interestingly, none of the participants reported either a change in mood or unusual side effects. The study authors theorize that the action on the amygdala has both immediate benefits on an unconscious level and longer term effects on anxiety.
Depression is often described as a constellation of symptoms and effects. Because of its many manifestations, the disease is a long way from being fully understood. There is currently no fool-proof, one-size-fits-all treatment for depression. Research on antidepressant medications like Celexa helps us identify what’s happening in the depressed brain. Armed with that knowledge, we can tailor more effective medications in the future. The study under discussion, for example, highlights the possibility that Celexa’s beneficial effects begin with the amygdala, the brain’s primitive fear center. More importantly, these effects begin almost immediately, contrary to previous assumptions.
References
Murphy, S., Norbury, R., O’Sullivan, U., Cowen, P., Harmer, C. (2009). Effect of a single dose of citalopram on amygdala response to emotional faces. British Journal of Psychiatry, 194(6), 535-540.
Irritable bowel syndrome (IBS) is a relatively common condition that results in abdominal discomfort, bloating, diarrhea, and constipation. According to the Mayo Clinic, IBS develops more often in women than in men and is also more likely to develop before the age of 35. Unlike other diseases that affect the intestines, IBS causes no permanent damage and does not appear to increase the risk of colon cancer. Mild and moderate cases of the condition can often be managed with lifestyle changes rather than medication. In more severe cases of IBS, certain prescription medications have been shown to reduce symptoms and improve quality of life.
Tricyclic antidepressants, the so-called first generation of antidepressant medications, have for years been prescribed to people with serious cases of IBS. There are several competing theories as to why these medications work so well for this condition. On the one hand, tricyclics have pain-relieving properties as one of their secondary effects. Less pain may lead a patient to report symptomatic improvement, particularly if pain was his or her dominant complaint. Another theory maintains that IBS is somehow linked with depression, and a reduction in the symptoms of depression may simultaneously reduce symptoms of IBS. The connection between mental state and IBS is not well understood and demands further research. Yet a third theory maintains that tricyclics alter the way the brain processes nerve signals from the intestines. This may lead to a more relaxed colon or less urgent or painful feelings when having a bowel movement.
Clinical researchers in Belgium surmised that newer antidepressant medications might be just as effective against IBS as the older tricyclics, with potentially fewer adverse effects. They conducted a trial with Celexa (citalopram) to determine its usefulness in managing IBS symptoms. Celexa belongs to the class of antidepressants known as selective serotonin reuptake inhibitors. What little research has been done on these medications and IBS has been promising. An earlier study showed that Celexa works to relax the colon shortly after food consumption, a possibly therapeutic action for anyone with IBS. The most recent study involved a crossover design with a placebo-controlled group. After an initial treatment period, the groups switched places for a second treatment period. Participants kept daily journals of their symptoms, and examinations during the trial provided empirical data. The results were significant but not as informative as the team had hoped. Celexa did lead to improvement of many symptoms but not bowel regularity. Interestingly, most participants reported a much improved sense of well-being that did not always match their objective symptom improvement. This suggests that Celexa’s psychotropic properties may have as much to do with its effectiveness on IBS patients as anything else.
Other studies with a similar approach have produced mixed results. The lesson here, according to the researchers, is that the emotional health and well-being of IBS patients cannot be neglected. A pharmaceutical solution is often sought when lifestyle changes and talk therapy might be more beneficial without the risk of side effects.
References
- PubMed Health [Internet]. (n.d.). Bethesda (MD): National Library of Medicine. Citalopram.  Retrieved March 10, 2012, from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001041/
- MayoClinic.com. (n.d.). Irritable bowel syndrome. Retrieved March 13, 2012, from http://www.mayoclinic.com/health/irritable-bowel-syndrome/DS00106
- Tack, J., Broekart, D., Fischler, B., Van Oudenhove, L., Gevers, A.M., Janssens, J. (2006). A controlled crossover stud of the selective serotonin reuptake inhibitor citalopram in irritable bowel syndrome. Neurogastroenterology, 55, 1095-1103.