A estimulacao transcraniana por corrente continua (ETCC) e uma tecnica nao-invasiva de estimulacao cerebral que consiste na aplicacao de uma corrente eletrica de baixa intensidade atraves de eletrodos colocados sobre a cabeca, levando a efeitos neuromodulatorios e de neuroplasticidade. Avaliamos o papel da ETCC no transtorno depressivo maior (TDM), uma condicao prevalente e cronica, atraves de um ensaio clinico duplo-cego, 2 x 2 (fatorial), com uma intervencao farmacologica (sertralina 50mg/dia) e uma nao-farmacologica (ETCC), comparando, portanto a eficacia e seguranca da ETCC ativa vs. simulada, vs. sertralina e da combinacao ETCC/sertralina vs. demais. Dos 850 voluntarios iniciais, incluimos aqueles com depressao moderada/grave, baixa ideacao suicida, ausencia de outras co-morbidades psiquiatricas e clinicas e que nao usavam (ou aceitaram retirar) medicacoes antidepressivas. Nao incluimos aqueles usando sertralina. Randomizamos os 120 participantes em 4 grupos: ETCC simulada/placebo (placebo), ETCC simulada/sertralina (sertralina), ETCC ativa/placebo (ETCC), ETCC ativa/sertralina (tratamento combinado). A ETCC foi aplicada em 2mA/25cm2, sendo o anodo e o catodo posicionados sobre as areas correspondentes ao cortex dorsolateral pre-frontal esquerdo e direito, respectivamente, por 30 minutos diarios, por dez dias consecutivos, excluindo finais de semana. Apos este periodo, duas outras estimulacoes, em semanas alternadas, foram realizadas ate o fim do estudo (6a semana). A ETCC simulada foi realizada da mesma maneira que a ETCC ativa, mas o aparelho era desligado apos 30 segundos iniciais. 103 participantes terminaram o estudo, sendo a analise estatistica por intencao de tratamento. A escala de depressao de Montgomery-Asberg (MADRS) foi o desfecho primario. No inicio, os quatro grupos eram semelhantes. Na 6a semana, o grupo tratamento combinado foi estatisticamente superior (p0,01 para todas as comparacoes) aos grupos placebo (diferenca de 11,5 pontos, Intervalo de Confianca [IC] 95%= 6-17), sertralina (8,5 pontos, IC 95%= 2,9-14) e ETCC (5,9 pontos, IC 95%= 0,36-11,43). ETCC e sertralina nao foram diferentes entre si (2,6 pontos, IC 95%=-2,9 a 8,1, p=0,35). Os resultados medidos por outras escalas foram semelhantes. Apenas vermelhidao na pele na regiao da estimulacao foi um efeito adverso mais observado na ETCC ativa. Os grupos tiveram desempenho semelhante nos testes cognitivos realizados, porem, de sete episodios de hipomania/mania, cinco foram no tratamento combinado. Nos estudos auxiliares, a ETCC nao levou a alteracoes na variabilidade da frequencia cardiaca (medida no inicio e ao fim do tratamento), tambem sugerindo seguranca da tecnica. Alem disso, observamos uma interacao entre o gene transportador da serotonina e a resposta a ETCC, sendo que o alelo curto (s) associou-se a uma pior resposta. Nao observamos interacoes com o polimorfismo Val66Met do BDNF. Finalmente, no estudo de seguimento, dos 42 pacientes que receberam ETCC quinzenal, por 3 meses, seguida de mensal, por 3 meses, a recaida foi de 47%. Em conjunto, os resultados demonstram que, na depressao aguda, a ETCC ativa e superior a simulada, comparavel a sertralina, e o tratamento combinado, superior aos demais. Clinicamente, a ETCC poderia substituir antidepressivos nos pacientes que nao toleram, nao podem ou nao desejam toma-los, ou combinada a estes, por exemplo, no tratamento de episodios graves / Transcranial direct current stimulation (tDCS) is a non-invasive technique of brain stimulation that applies a weak, direct electric current over ones scalp through electrodes, leading to neuromodulatory and neuroplastic effects. We evaluated the role of tDCS as a treatment for major depressive disorder (MDD), a chronic, prevalent condition, through a double-blind, 2x2 (factorial) trial, with one pharmacological (sertraline 50mg/day) and one non-pharmacological (tDCS) intervention; therefore comparing the efficacy and safety of active vs. sham tDCS, vs. sertraline and the combination active tDCS/sertraline vs. other interventions. Of 850 volunteers, we included only those with moderate-tosevere depression, low suicidal ideation, absence of other psychiatric and medical comorbidities and also those either not currently on antidepressants or using and agreeing to discontinue their use. We did not enrol patients on sertraline. The 120 patients were randomized into 4 groups: tDCS sham/placebo (placebo), tDCS sham/sertraline (sertraline), active tDCS/placebo (tDCS) and active tDCS/sertraline (combined treatment). TDCS was applied at 2mA/25cm2, with the anode and the cathode over the left and right dorsolateral prefrontal cortex, respectively, per 30 minutes daily, per 10 weekdays. Thereafter, tDCS was applied every other week, until the endpoint at 6 weeks (i.e., two extra sessions). For sham tDCS, the device was turned off after 30 seconds of stimulation. We performed an intention-to-treat analysis in the 103 patients who finished the study. The Montgomery- Asberg depression rating scale (MADRS) was the primary outcome. The four groups were similar at baseline. At week 6, the combined treatment group was significantly more effective (p0.01 for all comparisons) than placebo (mean difference of 11.5 points, 95% Confidence Interval [CI] =6-17), sertraline (8.5 points, 95% CI=2.9-14) and tDCS (5.9 points, 95% CI=0.36-11.43). TDCS and sertraline presented similar efficacy (2.6 points, 95% CI=-2.9 to 8.1, p=0.35). Other depression scales yielded similar results. The only adverse effect significantly more observed in the active tDCS was skin redness on the stimulated scalp region. The groups had similar performance in the cognitive assessments; although 5 of 7 (hypo)manic episodes were in the combined treatment group. The ancillary studies showed that tDCS treatment did not change heart rate variability (measured at baseline and endpoint), further suggesting that the intervention is safe. Moreover, there was an interaction between the short allele (s) of the serotonin transporter gene (5-HTTLPR) and lower tDCS antidepressant response; no association was observed with the Val66Met BDNF genotypes and tDCS response. Finally, we followed 42 patients for up to 24 weeks, performing tDCS sessions every other week for 3 months and then each month per 3 months, with a relapse rate of 47%. Taken together, these results showed that, for the acute depressive episode, active tDCS is more effective than sham, as effective than sertraline, and less effective than the combined treatment, which is the most effective. In clinical settings, tDCS could be either a substitutive treatment for antidepressants in patients that cannot or would not use them, or as an augmentative treatment that, combined with antidepressants, could boost clinical response in severe cases
| Identifer | oai:union.ndltd.org:usp.br/oai:teses.usp.br:tde-03122012-110639 |
| Date | 14 August 2012 |
| Creators | Brunoni, André Russowsky |
| Contributors | Benseñor, Isabela Judith Martins, Fregni, Felipe |
| Publisher | Biblioteca Digitais de Teses e Dissertações da USP |
| Source Sets | Universidade de São Paulo |
| Language | Portuguese |
| Detected Language | English |
| Type | Tese de Doutorado |
| Format | application/pdf |
| Rights | Liberar o conteúdo para acesso público. |
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