What Animal Research Says About Sexual Side-effects of SSRIs

Earlier this year, a group of researchers from Denmark examined the existing animal research on the sexual side-effects of antidepressants. They were interested in what the literature reveals about prolonged sexual side effects, as this has important implications for individuals who are prescribed SSRIs. In their review, the researchers found considerable evidence for long-term effects on measurable sexual behaviors in rats who were given SSRIs.

“The persistent effects of SSRIs on sexuality have been little studied in humans, and patients might not associate them with a drug they no longer take,” the researchers write.

In many ways, this study parallels the results of surveys done on people who have taken SSRI antidepressants. For example, most recently Medscape reported, based on a survey of about 1000 people currently taking a SSRI, that the “vast majority (88%) of respondents reported a loss of sexual desire, satisfaction, or sexual function.”  “More than two-thirds (68%) first experienced sexual problems as a symptom of their depression, and 17% first experienced sexual problems only after starting antidepressants.”

These reports are far from new. In another example, Bahrick reported in 2008 that there was a great disparity between the professional and non-professional literature in the reporting of sexual side effects. On the professional side she found limitations in both clinical trial data and post marketing research. Many studies relied on participants spontaneously self-reporting sexual side effects, which is often a sensitive topic that does not lend itself to open sharing.

She found that the most detailed and robust information actually came from sources like consumer reports on internet communities like SSRIsex, a Yahoo discussion group. These consumers tended to report that all sexual side effects that started while they were on the medication continued after they stopped taking them as well. The most common symptoms reported were “genital sensitivity or genital anesthesia, reduced intensity of orgasm or ejaculatory anhedonia, an absence of sexual thoughts or fantasies, erectile problems, and a severely diminished or absent libido.”

In the present study, the researchers found 14 experiments on rats that used an SSRI published between 2006 and 2013. The general quality of the studies was poor – only 4 reported randomizing rats into treatment and control groups. All studies used rats who had been exposed to an SSRI, most commonly fluoxetine or citalopram. For rats given SSRIs, there was a significantly higher rate of reduced sexual behaviors. Interestingly, the researchers report:

“Trials sponsored by the drug industry tended to show markedly different results than other trials, in some cases reporting an improvement in sexual function while other trials showed an impairment.”

All of this evidence is important for consumers to have as they make decisions about whether or not to take an SSRI. This informed consent process can become even more difficult when consumers do not even know they are taking an SSRI – as has been the case in the controversial approval of flibanserin (Addyi^TM) by the FDA for female sexual interest/arousal disorder.

Here we see how flibanserin, a serotonergic drug was approved to treat sexual dysfunction, but is itself an agent that may cause long-term sexual problems. Another source of information on the persistent of sexual side effects of SSRIs is case reports by physicians. Most of these document individuals who started SSRI treatment with no sexual problems, experienced a reduction in depression symptoms but developed sexual problems that persisted long after they discontinued the medication.

The researchers of this report conclude that “SSRIs can cause permanent impairment of sexual function,” and that this problem may be underestimated.

“Our results suggest that patients should be informed before they are being prescribed SSRIs that these drugs may cause long-lasting or perhaps even permanent harm on sexual function that persists after the patients have come off the drugs,” they write. “Our results also provide support to reports about other permanent harms caused by SSRIs.”

 

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Simonsen, A. L., Danborg, P. B., & Gøtzsche, P. C. (2016). Persistent sexual dysfunction after early exposure to SSRIs: Systematic review of animal studies. The International Journal Of Risk & Safety In Medicine, 28(1), 1-12. doi:10.3233/JRS-160668 (Full Text)