Side Effect Profiles of Selective Serotonin Reuptake Inhibitors

Depression and anxiety are major global health burdens. Although SSRIs targeting the serotonergic system are prescribed over 200 million times annually, they have variable therapeutic efficacy and side effects, and mechanisms of action remain incompletely understood. Here, we comprehensively characterise the molecular landscape of gene regulatory changes associated with fluoxetine, a widely-used SSRI. We performed multimodal analysis of SSRI response in 27 mammalian brain regions using 310 bulk RNA-seq and H3K27ac ChIP-seq datasets, followed by in-depth characterisation of two hippocampal regions using single-cell RNA-seq (20 datasets). Remarkably, fluoxetine induced profound region-specific shifts in gene expression and chromatin state, including in the nucleus accumbens shell, locus coeruleus and septal areas, as well as in more well-studied regions such as the raphe and hippocampal dentate gyrus. Expression changes were strongly enriched at GWAS loci for depression and antidepressant drug response, stressing the relevance to human phenotypes. We observed differential expression at dozens of signalling receptors and pathways, many of which are previously unknown. Single-cell analysis revealed stark differences in fluoxetine response between the dorsal and ventral hippocampal dentate gyri, particularly in oligodendrocytes, mossy cells and inhibitory neurons. Across diverse brain regions, integrative omics analysis consistently suggested increased energy metabolism via oxidative phosphorylation and mitochondrial changes, which we corroborated in vitro; this may thus constitute a shared mechanism of action of fluoxetine. Similarly, we observed pervasive chromatin remodelling signatures across the brain. Our study reveals unexpected regional and cell type-specific heterogeneity in SSRI action, highlights under-studied brain regions that may play a major role in antidepressant response, and provides a rich resource of candidate cell types, genes, gene regulatory elements and pathways for mechanistic analysis and identifying new therapeutic targets for depression and anxiety.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Integrative multi-omics landscape of fluoxetine action across 27 brain regions reveals global increase in energy metabolism and region-specific chromatin remodelling

et al. 2022

“…Since use of SSRIs for anxiety, OCD or depression seems unrelated to other comorbidities known to affect COVID morbidity and mortality (hypertension, diabetes, heart disease), direct impact of SSRIs on the risk factors for severe COVID-19 is minimal. There is one important caveat—the weight gain that may accompany use of some SSRIs [ 39 ].…”

Section: Discussionmentioning

confidence: 99%

Ongoing Use of SSRIs Does Not Alter Outcome in Hospitalized COVID-19 Patients: A Retrospective Analysis

Mendelson

et al. 2021

JCM

SARS-CoV-2 continues to have devastating consequences worldwide. Though vaccinations have helped reduce spread, new strains still pose a threat. Therefore, it is imperative to identify treatments that prevent severe COVID-19 infection. Recently, acute use of SSRI antidepressants in COVID+ patients was shown to reduce symptom severity. The aim of this retrospective observational study was to determine whether COVID+ patients already on SSRIs upon hospital admission had reduced mortality compared to COVID+ patients not on chronic SSRI treatment. Electronic medical records of 9044 patients with laboratory-confirmed COVID-19 from six hospitals were queried for demographic and clinical information. Using R, a logistic regression model was run with mortality as the outcome and SSRI status as the exposure. In this sample, no patients admitted on SSRIs had them discontinued. There was no significant difference in the odds of dying between COVID+ patients on chronic SSRIs vs. those not taking SSRIs, after controlling for age category, gender, and race. This study shows the utility of large clinical databases in determining what commonly prescribed drugs might be useful in treating COVID-19. During pandemics due to novel infectious agents, it is critical to evaluate safety and efficacy of drugs that might be repurposed for treatment.

“…Since use of SSRIs for anxiety, OCD or depression seems unrelated to other comorbidities known to affect COVID morbidity and mortality (hypertension, diabetes, heart disease), direct impact of SSRIs on the risk factors for severe COVID-19 is minimal. There is one important caveat and that is the weight gain that may accompany use of some SSRIs (19).…”

Section: (Which Was Not Certified By Peer Review)mentioning

confidence: 99%

Ongoing use of SSRIs and the hospital course of COVID-19 patients: a retrospective outcome analysis

Mendelson

et al. 2021

Preprint

Background: The SARS-CoV2 virus continues to have devastating consequences worldwide. Though vaccinations have helped to reduce the impact of the virus, new strains still pose a threat to unvaccinated, and to a lesser extent vaccinated, individuals. Therefore, it is imperative to identify treatments that can prevent the development of severe COVID-19. Recently, acute use of SSRI antidepressants in COVID+ patients has been shown to reduce the severity of symptoms compared to placebo. Since SSRIs are a widely used anti-depressant, the aim of this study was to determine if COVID+ patients already on SSRI treatment upon admission to the hospital had reduced mortality compared to COVID+ patients not on chronic SSRI treatment. Methods: A retrospective observational study design was used. Electronic medical records of 9,043 patients with a laboratory-confirmed diagnosis of Covid-19 from 03/2020 to 03/2021from six hospitals were queried for demographic and clinical information. Using R, a logistic regression model was run with mortality as the outcome and SSRI status as the exposure. An adjusted logistic regression model was run to account for age category, gender, and race. All tests were considered significant at p of 0.05 or less. Results: In this sample, no patients admitted on SSRIs had them discontinued. This is consistent with current recommendations. There was no significant difference in the odds of dying between COVID+ patients on chronic SSRIs vs COVID+ patients not taking SSRIs, after controlling for age category, gender, and race. The odds of COVID+ patients on SSRIs dying was 0.98 (95%CI: 0.81, 1.18) compared to COVID+ patients not on SSRIs (p=0.83). Conclusion: In times of pandemics due to novel infectious agents it is difficult, but critical to evaluate safety and efficacy of drugs that might be repurposed for treatment. This large sample size of 9,043 patients suggests that there will be no significant benefit to use of SSRIs to decrease mortality rates for hospitalized patients with Covid-19 who are not currently on SSRI medications. This study shows the utility of large clinical databases in addressing the urgent issue of determining what commonly prescribed drugs might be useful in treating COVID-19.