What are selective serotonin reuptake inhibitors SSRIs used to treat how do they work?
|
Depression and anxiety disorders are the most common mental health conditions in the United States, affecting about a quarter of the adult population (disproportionately women) each year, according to the National Institutes of Mental Health. The most widely prescribed medications for treating depression and anxiety disorders, including post-traumatic stress disorder (PTSD) and obsessive compulsive disorders (OCD), belong to a class of drugs known as selective serotonin reuptake inhibitors (SSRIs). SSRIs — such as Lexapro, Celexa, Zoloft, Paxil and Prozac — are believed to alleviate symptoms of depression, excessive worry and compulsivity by acting upon the brain’s chemistry — specifically by blocking the breakdown and reabsorption of the neurotransmitter serotonin in the spaces between neurons. This selective reuptake inhibition causes serotonin levels to rise, promoting neuronal firing in circuits of the brain associated with mood and anxiety. A closely related class of antidepressants, called serotonin and norepinephrine reuptake inhibitors (SNRIs), block the reabsorption of both serotonin and norepinephrine, another neurotransmitter believed to be important in regulating mood and pain perception. Effexor and Cymbalta are examples of SNRIs.  Kelly Lee, PharmD, associate professor of clinical pharmacy and associate dean at UC San Diego Skaggs School of Pharmacy and Pharmaceutical Sciences, discusses these medications and how to take them to maximize their potential benefits. Find the drug and dose that works for you “The brains of people are different,” Lee said. “Their ability to respond to a medication is different. We can’t predict which medication will work the best and we don’t know the effective dose until we see how the patient responds to the medication.” Recognize the side effects Sexual dysfunction, including delayed orgasm or ejaculatory disorders, is a common chronic side effect of some antidepressants. Teeth grinding or sweating may also persist. A rare and potentially serious side effect of SSRIs is an excessive release of antidiuretic hormone (SIADH), which often results in low sodium levels in the blood, a condition known as hyponatremia. Long-term use of SSRIs can also reduce bone density, which is why Lee recommends periodic bone density scans for her patients, especially older adults or those who are at risk of osteoporosis. Serotonin does not exist only in the brain, Lee explained, it is found also in the gut and the bloodstream. Adhere to your medication regimen “We do a lot of education on medication adherence because there are many patients who don’t understand how the drugs work or feel there is a stigma with a psychiatric diagnosis,” Lee said. “A person with type 1 diabetes should not stop taking their insulin. It is similar with a psychiatric condition. There is evidence that if you stop treatment early, your relapse risk is greater. We struggle with this with our patients a lot.” Lee adds that a patient should take a medication at the dose that treats symptoms completely and then remain on medication for another four months or more depending upon past history. “Stopping a medication too early can set patients up for relapse.” Know about drug interactions To learn more about the featured medical specialties, please visit:Psychiatry and Behavioral Health
Serotonin is a neurotransmitter, a brain messenger chemical that carries signals between nerve cells in the brain and is thought to be involved in regulating many functions, influencing emotions, mood, memory and sleep. It’s thought that selective serotonin reuptake inhibitor (SSRIs) medications work by altering and increasing the balance of serotonin levels in the brain. However, it is too simplistic to say that Obsessive-Compulsive Disorder is caused by low serotonin levels, but for reasons we still don’t understand, an increase in serotonin levels can improve symptoms for some people with OCD and make people more responsive to psychological treatments, such as CBT. But how do SSRI’s actually work?The brain is made up of millions of interconnected brain cells (neurons). Messages travel along these cells rather like electricity down a wire, but when the message reaches the end of the neuron, it has to jump the gap (synapse) to the next cell or group of cells. To do this the neuron releases tiny amounts of a neurotransmitter into the gap. Serotonin is one of these neurotransmitters. After carrying a message, serotonin is usually reabsorbed by the nerve cells (known as “reuptake”). It’s thought that SSRIs work by blocking (“inhibiting”) reuptake, meaning more serotonin is available to pass further messages between nearby nerve cells. In more details… These chemicals are sent out by one nerve cell into the space between it and the next. The next cell in line gets the message once those chemicals get to it from across the gap. That nerve cell then releases a chemical toward the next nerve cell so it gets the message. A key gene for this process is hSERT which has the instructions for making a serotonin transporter. The transporter’s job is to sop up extra serotonin after a nerve spits it toward the next nerve cell in line. In some people it’s thought hSERT might works too fast, and may collect all the serotonin before the next cell has heard the signal. To put it simply, their nerve cells are whispering when they should be speaking out loud. In order to allow the nerve to recover and receive the next message, the body has a clever way of removing the neurotransmitter from the receptors, and allowing it to be taken back into the originating nerve (re-uptake). The SSRIs slow down the collection of serotonin by transporters like hSERT and the process of returning the serotonin to the end of the neuron it comes from. This is thought to mean that serotonin stays in the space between the cells longer and increases the chances that the second cell will get the message. Summary We still don’t know exactly what the influences of serotonin are on OCD, and some people’s symptoms are not improved despite taking SSRIs. So sadly at this time taking medication might help, but can’t be assured, which is why we very much encourage people to focus their treatment on psychological therapy like Cognitive Behavioural Therapy (CBT). What to read next: How does a selective serotonin reuptake inhibitor SSRI work?After carrying a message, serotonin is usually reabsorbed by the nerve cells (known as "reuptake"). SSRIs work by blocking ("inhibiting") reuptake, meaning more serotonin is available to pass further messages between nearby nerve cells.
|
