Second-generation anti-depressants and risk of new-onset seizures in the elderly

Antidepressant use and the risk of seizure: a meta-analysis of observational studies

PURPOSE

The association between antidepressant use and the risk of seizures remains controversial. Therefore, this meta-analysis examined whether antidepressant use affects the risk of seizures.

METHODS

To identify relevant observational studies, we conducted systematic searches in PubMed and Embase of studies published through May 2023. Random-effects models were used to estimate overall relative risk.

RESULTS

Our meta-analysis included eight studies involving 1,709,878 individuals. Our results showed that selective serotonin reuptake inhibitors (SSRI) (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.32-1.66; P < 0.001) and selective noradrenalin reuptake inhibitors (SNRI) (OR 1.65, 95% CI 1.24-2.19; P = 0.001), but not tricyclic antidepressants (TCA) (OR 1.27, 95% CI 0.84-1.92; P = 0.249), were associated with an increased risk of seizures. Subgroup analyses revealed an OR of 2.35 (95% CI 1.7, 3.24; P < 0.001) among short-term (< 30 days) antidepressant users.

CONCLUSIONS

The findings of this meta-analysis support an increased risk of seizures in new-generation antidepressant users, expanding previous knowledge by demonstrating a more pronounced risk in short-term users.

Fluoxetine Can Cause Epileptogenesis and Aberrant Neurogenesis in Male Wild-Type Mice

Antidepressants in general, and fluoxetine in particular, increase adult hippocampal neurogenesis (AHN) in mice. Here we asked how the antidepressant fluoxetine affects behavior and AHN in a corticosterone model of depression. In three groups of adult male C57BL/6j mice, we administered either vehicle (VEH), corticosterone (CORT) treatment to induce a depression-like state, or corticosterone plus a standard dose of fluoxetine (CORT+FLX). Following treatment, mice performed the open field test, the novelty suppressed feeding (NSF) test, and the splash test. Neurogenesis was assessed by means of immunohistochemistry using BrdU and neuronal maturation markers. Unexpectedly, 42% of the CORT+FLX-treated mice exhibited severe weight loss, seizures, and sudden death. As expected, the CORT-treated group had altered behaviors compared to the VEH group, but the CORT+FLX mice that survived did not show any behavioral improvement compared to the CORT group. Antidepressants generally increase neurogenesis and here we also found that compared to CORT mice, CORT+FLX mice that survived had a significantly greater density of BrdU+, BrdU+DCX+, and BrdU+NeuN+ cells, suggesting increased neurogenesis. Moreover, the density of BrdU+NeuN+ cells was increased in an aberrant location, the hilus, of CORT+FLX mice, similar to previous studies describing aberrant neurogenesis following seizures. In conclusion, fluoxetine could induce considerable adverse effects in wild-type mice, including seizure-like activity. Fluoxetine-induced neurogenesis increases could be related to this activity; therefore, proneurogenic effects of fluoxetine and other antidepressants, especially in the absence of any behavioral therapeutic effects, should be interpreted with caution.

A nationwide study of initiation of antidepressant pharmacotherapy and the risk of seizures

OBJECTIVE

The present study aimed to examine whether antidepressant initiation increases the risk of hospitalizations and unplanned outpatient visits for seizures. Research has provided conflicting evidence as to whether antidepressant initiation causes seizures. Because epilepsy and depression are comorbid, this remains an important question, particularly in the care of those already at-risk for seizures.

METHODS

We used Swedish-register data, including 658,766 antidepressant initiators and 1:1 age-, region-, and sex-matched non-initiators, ages 12-65. We used filled prescriptions to identify any antidepressant and serotonergic antidepressant and inpatient hospitalizations and unplanned outpatient (to avoid coding routine epilepsy maintenance as a seizure) visits to identify seizures, respectively. We first compared seizure visit incidence between antidepressant-initiators and matched non-users in the year following initiation from 2006 to 2013. To examine seizure risk over months pre- and post-initiation, within-individual analyses compared risk during the month one year prior to initiation with all subsequent months. We examined associations for any antidepressant and serotonergic antidepressants, as well as for any initiator and initiators with a history of seizures.

RESULTS

Our matched-cohort results showed higher incidence of seizure visits among antidepressant users compared with non-users (e.g., adjusted incidence rate ratio [IRR]=3.14, 95% confidence interval [CI]=2.83-3.49). In within-individual analyses, the months after initiation were associated with higher incidence of seizure visits when compared with the month one year prior to initiation (e.g., one month after initiation IRR=1.96, 95%CI=1.64-2.34), but in individuals with a seizure history we observed weaker or no associations in the months after initiation (e.g., two months after initiation IRR=1.12, 95%CI=0.87-1.45). Notably, irrespective of potential seizure history, the months preceding initiation were associated with the greatest risk (e.g., one month before initiation IRR=2.86, 95% CI=2.42-3.38).

CONCLUSIONS

Our findings suggest that there may be an elevated risk of seizures during antidepressant treatment, though the period of highest risk was before the initiation of antidepressants. Risk for seizure visits was lower among individuals with a history of prior seizures, which may be reassuring for the clinical care of these patients or indicate lack of treatment seeking following seizures. This study highlights the need to consider seizure risk across time; the failure to account for these dynamics may help account for discrepant findings in previous studies.

Response to sertraline and antiepileptic drugs in pentylenetetrazole kindling in rats

Anti-epileptic drugs (AEDs) are the mainstay of epilepsy treatment but these may be a potential risk factor for behavioral disturbances particularly depression which requires treatment. In this study, the effect of antidepressant sertraline (SRT) in combination with AEDs sodium valproate (SV) and levetiracetam (LEV) on seizures, cognitive impairment and oxidative stress in rats was evaluated. After administration of 24th injection of pentylenetetrazole (PTZ), 77.8% rats were kindled. Administration of SRT showed no protective effect on kindling development while SV was 100% protective. With LEV 42.9% were kindled. On combining SRT with SV or LEV 25% and 20% rats were kindled. A significant increase in latency to reach platform zone in Morris water maze(MWM), and increased transfer latencies in Elevated plus maze(EPM) was observed in PTZ kindled rats as compared to normal control on day 49 and when LEV was combined with SRT. In EPM test, however none of the drug treatments had any effect on transfer latencies except LEV pretreated kindled group. In Passive avoidance (PA) test, kindling was associated with a significant decrease in retention time(p = 0.018) while LEV and SV had no effect. The PTZ kindled rats showed significantly higher malondialdehyde(MDA) levels in brain hippocampus(p = 0.0286) while both SRT and SV were associated with significantly lower MDA levels as compared to kindled control group. In case of glutathione (GSH), kindling had no significant effect. The use of sertraline for depression in persons with epilepsy on AEDs needs to be carefully evaluated and monitored due to likelihood of individual variation.