Selective Serotonin Reuptake Inhibitors: How Do SSRIs Improve Mood And What Are Their Side Effects?

When SSRIs were first introduced, they were revolutionary — not only is this class of antidepressants generally very effective at relieving the symptoms of depression, it is also much less likely than some other antidepressants to cause debilitating side effects that would make your life hell in a whole different way. It's no surprise that selective serotonin reuptake inhibitors are among the most popular class of antidepressant out there today. 

What Are SSRIs, and how do they work?

"SSRI" is much less of a mouthful than the words it stands for — selective serotonin reuptake inhibitors — but this full name gives important insights into how these antidepressants are believed to relieve depression:

• Serotonin is a neurotransmitter — a kind of brain chemical that transmits messages in the brain — with a variety of functions relating to mood, memory, learning, and the way in which we process reward. 
• "Reuptake" refers to absorption, and "inhibitor" means blocker — so put very simply, SSRIs prevent the absorption of serotonin within the brain, making more of this neurotransmitter available. 
• "Selective" means that SSRIs specifically target serotonin while leaving other neurotransmitters alone, which is one of the reasons these antidepressants cause fewer side effects than less targeted ones. 

SSRIs are also prescribed to help people with other mental health conditions, including anxiety disorders, panic disorders, post-traumatic stress disorder, chronic pain, and obsessive compulsive disorder. 

Commonly prescribed SSRIs include:

• Fluoxetine, the first SSRI to be introduced, also sold under the brand names Prozac and Sarafem. 
• Sertraline (Zoloft) 
• Escitalopram (Lexapro)
• Paroxetine (Paxil)
• Citalopram (Celexa)
• Fluvoxamine (Luvox)
• Vilazodone

How effective are SSRIs?

It will probably come as no surprise that research has found SSRI antidepressants to be more effective than "treatment" with a placebo. Any antidepressant, of any class, has actually been shown to have about a 50 percent chance of helping any given individual with depression feel better, making antidepressants in general pretty effective. 

How do SSRIs measure up to other kinds of antidepressants, though? Some studies have found tricyclic antidepressants (also known as TCAs) to be better at offering relief from the symptoms of depression, while other research has concluded that TCAs and SSRIS are equally effective at treating depressive disorders.

SSRIs, however, have fewer side effects, which translates to a higher chance that patients will actually keep taking them. Since someone must, obviously, take an antidepressant for it to have the chance to be effective, that means a lot. SSNRIs, another class of antidepressants, have also been shown to work just as well as SSRIs. 

What are the side effects of SSRIs for depression?

When SSRI antidepressants first hit the market, they were believed to come with basically no side effects. Over time, a more complete picture has emerged. If you were prescribed an SSRI, you should know that they can cause the following side effects:

• Sexual dysfunction — both a lowered or non-existent libido and erectile dysfunction can fall under this heading, and though studies reveal that only around seven percent of patients will report the fact that their sexual life has suffered since they started taking SSRIs to their doctor without being prompted, closer to half of patients will admit to sexual changes if asked. 
• Weight gain — after initial weight loss, a subset of people taking SSRIs will subsequently gain weight. It appears that citalopram is the SSRI that is least likely to cause this side effect. If you were working on losing weight or hoping to, mention this to your prescribing doctor before you start taking an antidepressant. 
• Some people will experience sleep disturbances while taking an SSRI. 
• Blurred vision is another possible side effect. 
• Some people will feel dizzy, nauseous, or even vomit. 
• A subset of people taking SSRIs will also feel agitated and restless. 

Contraindications: Who shouldn't take SSRIs?

While SSRIs generally have a lower risk than some other antidepressants of interacting with other medications you may be taking, it is always important to let your doctor know exactly what other drugs you take. This includes over the counter medications as well as prescription medications. If necessary, your doctor will either prescribe you a different antidepressant, or see if it is possible to switch your other medications to drugs that do not interact badly with your SSRI. 

Women who are trying to conceive, pregnant, or breastfeeding aren't generally advised to take SSRIs because it is not clear whether this is safe, but your doctor will determine whether the advantages are greater than the potential risk on an individual basis. Children and teenagers, meanwhile, may be prescribed SSRIs the expected benefits are deemed to outweigh the risks — but with caution. The same holds true for people with underlying conditions like diabetes, kidney disease, and epilepsy.