Background.-Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the central nervous system (CNS) that preferentially targets the spinal cord and optic nerves. Increasing disability is accrued with each inflammatory attack. Disability has been shown to be an independent predictor of poor quality of life in those with NMOSD. Factors associated with increasing disability need further systematic investigation.Methods.-We performed a multi-center retrospective chart analysis of aquaporin-4 (AQP4) seropositive NMOSD patients with a history of myelitis seen at five large referral centers for

IntroductionGabapentin has been extensively prescribed off-label for psychiatric indications, with little established evidence of efficacy. Gabapentin and pregabalin, a very similar drug with the same mechanism of action, bind to a subunit of voltage-dependent calcium channels which are implicated in the aetiopathogenesis of bipolar disorder, anxiety and insomnia. This systematic review and meta-analysis aims to collect and critically appraise all the available evidence about the efficacy and tolerability of gabapentin and pregabalin in the treatment of bipolar disorder, insomnia and anxiety.Methods and analysisWe will include all randomised controlled trials (RCTs) reported as double-blind and comparing gabapentin or pregabalin with placebo or any other active pharmacological treatment (any preparation, dose, frequency, route of delivery or setting) in patients with bipolar disorder, anxiety or insomnia. For consideration of adverse effects (tolerability), single-blind or open-label RCTs and non-randomised evidence will also be summarised. The main outcomes will be efficacy (measured as dichotomous and continuous outcome) and acceptability (proportion of patients who dropped out of the allocated treatment). Published and unpublished studies will be sought through relevant database searches, trial registries and websites; all reference selection and data extraction will be conducted by at least 2 independent reviewers. We will conduct a random-effects meta-analysis to synthesise all evidence for each outcome. Heterogeneity between studies will be investigated by the I2 statistic. Data from included studies will be entered into a funnel plot for investigation of small-study effects. No subgroup analysis will be undertaken, but we will carry out sensitivity analyses about combination treatment, psychiatric comorbidity, use of rescue medications and fixed versus random-effects model.Ethics and disseminationThis review does not require ethical approval. This protocol has been registered on PROSPERO (CRD42016041802). The results of the systematic review will be disseminated via publication in a peer-reviewed journal.

The gabapentinoids, gabapentin, and pregabalin, target the α2δ subunits of voltage-gated calcium channels. Initially licensed for pain and seizures, they have become widely prescribed drugs. Many of these uses are off-label for psychiatric indications, and there is increasing concern about their safety, so it is particularly important to have good evidence to justify this usage. We conducted a systematic review and meta-analysis of the evidence for three of their common psychiatric uses: bipolar disorder, anxiety, and insomnia. Fifty-five double-blind randomised controlled trials (RCTs) and 15 open-label studies were identified. For bipolar disorder, four double-blind RCTs investigating gabapentin, and no double-blind RCTs investigating pregabalin, were identified. A quantitative synthesis could not be performed due to heterogeneity in the study population, design and outcome measures. Across the anxiety spectrum, a consistent but not universal effect in favour of gabapentinoids compared to placebo was seen (standardised mean difference [SMD] ranging between -2.25 and -0.25). Notably, pregabalin (SMD -0.55, 95% CI -0.92 to -0.18) and gabapentin (SMD -0.92, 95% CI -1.32 to -0.52) were more effective than placebo in reducing preoperative anxiety. In insomnia, results were inconclusive. We conclude that there is moderate evidence of the efficacy of gabapentinoids in anxiety states, but minimal evidence in bipolar disorder and insomnia and they should be used for these disorders only with strong justification. This recommendation applies despite the attractive pharmacological and genetic rationale for targeting voltage-gated calcium channels.