Neurofeedback Treatment on Depressive Symptoms and Functional Recovery in Treatment-resistant Patients With Major Depressive Disorder: an Open-label Pilot Study

Major depressive disorder (MDD) is a severely disabling disorder resulting in the deterioration of daily function and lowering quality of life. The lifetime prevalence of depression is 10-15%, and the annual prevalence of MDD in the United States is approximately 7%. The World Health Organization has reported that MDD is expected to be the top disease in terms of global burden by 2030. Fifty percent of patients with depressive disorder have a chronic disease course, and 20% of such patients have insufficient responses to treatment despite the use of antidepressant medication. In addition, although antidepressants have been shown to be effective, residual symptoms may continue by stopping the medication early due to inconvenient side effects of the medication. Sixty percent of patients with depressive disorder have poorer executive function. Patients with depressive disorder are continuously affected by deficits in social functioning, such as interpersonal relationships and job adaptation, even if some of their symptoms are improved by medication. Therefore, various additional treatments other than antidepressant treatment have been tried to improve residual depressive symptoms and the remission rate.

Brain waves have been used to measure brain activity and previous studies have reported that different brain waves reflect different brain states, including moods. Neurofeedback is a type of electroencephalography (EEG) training that allows individuals to change the levels of particular types of brain waves displayed on a computer by operational conditioning. EEG studies showed that the neurofeedback is capable of generating long term changes in the spectral EEG topography, while neuroimaging studies represented the neuroplastic effects from neurofeedback treatment. Neurofeedback is an alternative approach that aims to help individuals alter brain activation without introducing electrical or magnetic activity, or pharmacological compounds into the brain, hence preventing the brain from becoming dependent on outside influences for better functioning. It is noninvasive method and there's no report of even minor side effects.

Neurofeedback may be considered a new augmentation treatment for patients with treatment-resistant depression (TRD), even after the use of antidepressants. Some studies have reported improvements in both depressive symptoms and executive function following neurofeedback treatment. A recent article insisted that neurofeedback treatment for depression as having "revealed promising effects in recent clinical trials". However, most such studies have been case reports or uncontrolled studies, and the mechanism underlying the treatment effects of neurofeedback are still unclear. In addition, there has been no study of neurofeedback on depressive symptoms and functional recovery in patients with TRD.

Brain-derived neurotrophic factor (BDNF) acts on certain neurons of the central nervous system and the peripheral nervous system. It helps support the survival of existing neurons and encourages the growth and differentiation of new neurons and synapses. Previous studies have suggested the presence of an etiological link between the development of depression and BDNF. However, no studies have examined the association between neurofeedback and changes in BDNF level.

The purpose of this pilot study was to evaluate the effects of neurofeedback as an augmentation treatment on depressive symptoms and functional recovery in patients with TRD. The investigators also aimed to identify the usefulness of BDNF as a biomarker for neurofeedback by examining changes in the BDNF level before vs. after treatment in the neurofeedback treatment and medication-only (treatment as usual, TAU) groups.