RESUMO
Transcranial direct current stimulation (tDCS) has been increasingly applied in fibromyalgia (FM) to reduce pain and fatigue. While results are promising, observed effects are variable, and there are questions about optimal stimulation parameters such as target region (e.g., motor vs. prefrontal cortices). This systematic review aimed to provide the latest update on published randomized controlled trials with a parallel-group design to examine the specific effects of active tDCS in reducing pain and disability in FM patients. Using the PRISMA approach, a literature search identified 14 randomized controlled trials investigating the effects of tDCS on pain and fatigue in patients with FM. Assessment of biases shows an overall low-to-moderate risk of bias. tDCS was found effective in all included studies conducted in patients with FM, except one study, in which the improving effects of tDCS were due to placebo. We recommended tDCS over the motor and prefrontal cortices as "effective" and "probably effective" respectively, and also safe for reducing pain perception and fatigue in patients with FM, according to evidence-based guidelines. Stimulation polarity was anodal in all studies, and one single-session study also examined cathodal polarity. The stimulation intensity ranged from 1-mA (7.14% of studies) to 1.5-mA (7.14% of studies) and 2-mA (85.7% of studies). In all of the included studies, a significant improvement in at least one outcome variable (pain or fatigue reduction) was observed. Moreover, 92.8% (13 of 14) applied multi-session tDCS protocols in FM treatment and reported significant improvement in their outcome variables. While tDCS is therapeutically effective for FM, titration studies that systematically evaluate different stimulation intensities, durations, and electrode placement are needed.
RESUMO
OBJECTIVES: Despite the burden of negative symptoms on quality of life in schizophrenic patients, no completely effective treatment has been developed to address such symptoms yet. Abnormalities in oxidative stress pathways have been recently demonstrated to be involved in the pathophysiology of schizophrenia, and a growing interest in antioxidant agents is emerging for targeting negative symptoms of schizophrenia. N-Acetylcysteine (NAC) is a potent antioxidant with neuroprotective properties. This study aimed to evaluate the possible effects of NAC as an adjunct to risperidone in treating negative symptoms of schizophrenia. MATERIALS AND METHODS: In this randomized, double-blind, placebo-controlled, parallel-group study, 42 patients with chronic schizophrenia and a score of 20 or greater on the negative subscale of positive and negative syndrome scale (PANSS) were enrolled in the active phase of their illness. The participants were equally randomized to receive NAC (up to 2 g/d) or placebo, in addition to risperidone (up to 6 mg/d) for 8 weeks. The participants were rated using PANSS every 2 weeks, and the decrease of PANSS negative subscale score was considered as our primary outcome. RESULTS: By the study end point, NAC-treated patients showed significantly greater improvement in the PANSS total (P = 0.006) and negative subscale (P < 0.001) scores than that in the placebo group, but this difference was not significant for positive and general psychopathology subscales. There was no significant difference between the 2 groups in the frequency of adverse effects. CONCLUSIONS: NAC add-on therapy showed to be a safe and effective augmentative strategy for alleviating negative symptoms of schizophrenia.