Adverse Effects of SSRIs

Author: Flavio Guzman, MD

The video below is a brief (length 2:30) overview on the adverse effects of SSRIs.


  • General concepts
  • Gastrointestinal side effects
  • CNS adverse effects:
    • Basal ganglia
    • Mental effects
  • Sexual dysfunction

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SSRIs-adverse-effects-1Hello, this is Dr. Flavio Guzman, I´m the editor of Psychopharmacology Institute.

In this short video I’m going to review adverse effects of selective serotonin reuptake inhibitors.




SSRIs-adverse-effects-2I´ll start reviewing some facts about SSRI therapy.
The first one is that patients tolerate the SSRIs better than tricyclic antidepressants.
Most side effects are acute. They tend to diminish over days and weeks.
And these side effects include nausea, diarrhea, cramping, heartburn, and other symptoms of GI distress.


SSRIs-adverse-effects-3We’re going to classify side effects according to the system they affect:
First we are going to review gastrointestinal side effects. Then central nervous system side effects and finally sexual dysfunction induced by SSRIs.




SSRIs-adverse-effects-4Nausea and vomiting are caused by stimulation of serotonin 3 receptors located at the hypothalamus and the brainstem.





Effects on the GI tract are mediated stimulation of serotonin 3 and 4 receptors. This stimulation can lead to increased GI motility, GI cramps. If the increase in GI motility is severe enough this can lead to diarrhea.




SSRIs-adverse-effects-6CNS side effects at the basal ganglia are mediated by 5HT2A receptor stimulation. Stimulation at the basal ganglia of these receptors can cause:

– Akathisia,
– Psychomotor retardation
– Parkinsonism
– Distonic movements.

SSRIs-adverse-effects-7Mental side effects is the second group of CNS side effects. Stimulation of 5HT2A and 5HTC receptors can lead to mental agitation, anxiety and panic attacks.



SSRIs-adverse-effects-8And finally, regarding sexual dysfunction patients may complain about: diminished libido, anorgasmia, impotence and delayed ejaculation





•Schatzberg, A; Cole, J; Debattista, C “Manual of Clinical Psychopharmacology”. 8th edition. American Psychiatric Publishing, 2010
•Stahl, S. ” Stahl’s Essential Psychopharmacology: Neuroscientific Basis and Practial Applications “. 4th ed. Cambridge University Press, 2013.

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