Adverse psychiatric effects of disease-modifying therapies in multiple Sclerosis: A systematic review

Psychiatric comorbidity is prevalent in persons with multiple sclerosis (MS). Few studies have assessed whether second-generation disease-modifying therapies (DMT) are associated with adverse psychiatric effects.

We aimed to systematically review the literature regarding the APEs associated with natalizumab, fingolimod, dimethyl fumarate, teriflunomide and alemtuzumab in MS. As a secondary objective, we evaluated changes in anxiety or depression scores following treatment with the aforementioned DMTs.

We searched MEDLINE, EMBASE, International Pharmaceutical Abstracts, PsychINFO, Central Register of Controlled Trials & Cochrane database of systematic reviews for published studies, and clinicaltrials.gov and regulatory documents from the US and Canada for unpublished studies. Data sources were searched from inception to September 2017. Studies reporting adverse psychiatric effects involving any DMT of interest were included. We report the incidence proportions of the adverse psychiatric effects and, where applicable, risk differences between DMT-exposed and unexposed individuals along with the corresponding 95% confidence intervals. We calculated the standardized mean differences (SMD) of changes in anxiety and depression scores if reported as study outcomes, and pooled the data using random effects meta-analysis.

Of 4389 abstracts screened, 78 met the inclusion criteria, including 48 clinical trials, 28 observational studies and 2 case reports. Depression was the most commonly reported adverse psychiatric effect. Incidence proportions for all adverse psychiatric effects ranged from 0 to 24.7%. None of the DMT studied were associated with a statistically significant increased risk of any adverse psychiatric effect (range of risk difference: -7.69% [95%CI: -16.06%, 5.56%] to 6.67 [-8.56, 15.59]). Eighteen studies examined changes in depression or anxiety following fingolimod, natalizumab or dimethyl fumarate treatment; depression symptoms improved in fingolimod-treated groups (SMD [95%CI]: 1.18 [0.17, 2.19]). We did not identify studies examining changes in these outcomes following treatment with any of the other DMTs.

The DMTs reviewed were not associated with an increased risk of adverse psychiatric effect in MS, and some may reduce the incidence of depressive symptoms. This may reflect either a positive direct effect (e.g. immune modulation) or an indirect effect arising due to a positive impact on disease activity or course.