In Australia, it is estimated that 1 million adults experience depression in any given year (BeyondBlue). Over half of people who experience depression will experience anxiety at the same time. On average, 1 in 5 women and 1 in 8 men in Australia will experience depression at least once during their life, and for some that will be quite minor symptoms while for others it will be severe.

Underlying pathophysiological mechanisms have been identified in depression and research has shown that neurofeedback can target these physiological mechanisms in order to reduce depressive symptoms.

So how can Neurofeedback help?

Very simply explained, people who have depression also show asymmetry in their frontal lobe. Specifically, the left frontal lobe has significantly less activation in people with depression than in people without depression. This was first researched in the 70s, so that research into NF and depression date back over 45 years. The initial studies looked at parietal alpha and asymmetries. Later studies in the 80s and 90s also looked at frontal alpha asymmetry, finding a relative hyper-activation of the right frontal cortex that was not found in the parietal cortex. It has been suggested that this is related to ‘approach’ and ‘withdrawal’ behaviours. Decreased left-sided frontal activation is thought to be associated with a deficit in the approach system (which can generate positive moods), hence people with these deficits are more prone to depressive disorders. Right-sided frontal activation is related to withdrawal related emotion such as anxiety disorders.

There have been some questions of stability of frontal alpha over time suggesting several measures may be worthwhile. It is thought that this stability may be related to the fact that alpha is usually seen in occipital and parental areas, and can often be very low in frontal regions- possibly too low to result in a reliable asymmetry comparison. rTMS, a way of stimulating the brain through magnetic current, has been shown to be helpful in depression by stimulating the left frontal cortex, or inhibiting the right frontal cortex.

Neurofeedback allows us to increase left frontal lobe activation, which has been found to result in a large reduction of depressive symptoms, even sometimes resulting in a complete absence of depression by the end of the neurofeedback treatment (Hammond, 2005).

A systematic review conducted by Trambaiolli and colleagues (2021) examined the efficacy of EEG and fMRI neurofeedback training for treating major depressive disorder. The review included 24 total studies, 13 for EEG and 11 for fMRI, with EEG studies focusing primarily on frontal regions and fMRI studies targeting limbic area. Despite the experimental procedures varying greatly across studies, all reported clinically meaningful improvements in depression symptoms. While this review revealed that smaller effects are seen when comparing NF to an alternative treatment control than to placebo controls, NF was still more efficacious overall. Therefore, neuromodulation appears to robustly improve symptom severity in major depressive disorder, regardless of the procedure and experimental set up.

Harris & Colleagues (2021) looked at the effects of NF on depression in a population of college students with ADHD. The results showed that NF significantly reduced the number of depression symptoms displayed by the students and that this change persisted four weeks after the last NF session. This suggests that NF can be used to reduce symptoms of depression in people with ADHD.

Depression is characterised by reduced connectivity between the Prefrontal Cortex and limbic areas, such as the amygdala and hippocampus.  Quevedo and colleagues (2020) attempted to treat depressed adolescents by providing neurofeedback to increase the connectivity between these regions.  They found that neurofeedback produced greater connectivity between regions and was positively associated with rumination and depression change.

In 2020, Mennen and colleagues conducted a proof-of-concept study to explore the ability of fMRI neurofeedback training to reduce negative biases in depression. In this experiment participants had to perform a go/no go task while ignoring superimposed negative emotion faces. If attention was directed to the faces, the images of the faces would become more prominent and thus increase task difficulty. Using this task with NF, they trained 15 individuals with major depressive disorder and 12 controls over 3 sessions. Results demonstrated that NF led to a reduction in both negative attentional biases and overall depressive symptoms in depressed participants.

Yu and colleagues (2020) conducted a study in order to examine how depression is affected by EEG neurofeedback protocol which aims to enhance activation of target peak alpha frequency (PAF) in the prefrontal region. Thirty university-aged participants with mild depression were randomly allocated to either neurofeedback or a sham control (which consisted of brain wave measurements without any feedback). Both the neurofeedback and sham control consisted of 20 sessions. Depression, rumination, and executive function were measured in all participants before and after treatment. Participants who underwent neurofeedback showed significantly reduced depression and rumination as well as increased executive functioning compared to participants who underwent the sham control.

Wang and colleagues (2019) investigated the effects of alpha-asymmetry neurofeedback (ALAY) and high-beta down-training (Beta) neurofeedback on people with comorbid major depressive disorder (MDD) and anxiety. Eighty-seven participants with both MDD and anxiety were assigned to receive ALAY, Beta, or a no-treatment control for ten sessions.  For participants receiving neurofeedback (either ALAY or Beta), depression and anxiety decreased following treatment compared to pre-treatment (whereas participants in the control group showed no difference in depression or anxiety). This study suggests that both ALAY and Beta neurofeedback may be effective in treating MDD with comorbid anxiety.

Zahn & Colleagues (2019) conducted a systematic review on the effects of NF on depression in patients with major depression disorder (MDD).  They found evidence demonstrating that NF reduced depression symptoms in patients with MDD when reinforcing their brain responses to positive pictures, or their amygdala responses to autobiographical memories compared to control NF. This suggests that target NF can be used to reduce symptoms of depression in patients with MDD.

Mehler and Colleagues (2018) looked at the effects of NF on emotion-regulating brain regions compared to visual-activated brain regions (control) in patients with depression.  They found that both types of targeted NF significantly reduced depression symptoms in the patients by 40% on the Hamilton Depression Rating Scale.

A literature review by Linhartova and colleagues (2019) examined fMRI neurofeedback and the efficacy in treating emotional regulation. 51 studies in this type of neurofeedback alone were identified. The results showed that NF in various brain regions (amygdala, anterior insula, and anterior cingulate cortex) induces some effects on brain regulation, cognitive variables, and clinical variables. Generally, the success of  NF training is related to the combination of target brain region, the type of emotion regulation task, and the population undergoing the training. In terms of patient groups, the strongest support for the beneficial effects of fMRI-NF has been shown in increased positive emotion experiencing in patients with depression and in decreased anxiety in patients with anxiety disorders. Symptom reduction following NF training has been also reported in patients with PTSD, BPD, and schizophrenia.

Under double-blind conditions, Young and colleagues (2018) investigated the effects of real time functional MRI neurofeedback training (rtfMRI-nf) on participants with Major Depressive Disorder (MDD) during positive autobiographical memory (AM) recall. One group received rtfMRI-nf targeting the amygdala (known to be implicated in the pathophysiology of mood disorders), and the control group received rtfMRI-nf targeting the parietal region of the brain. The study aimed to find correlations between changes in depression scores and changes in amygdala connectivity. Results showed that, for the amygdala-targeted group, neurofeedback training during positive AM recall increased connectivity of the amygdala with regions involved in self-referential, salience, and reward processing. During positive memory recall, specific amygdala connectivity (amygdala-left precuneus) was significantly correlated with improvement in depressive symptoms.

In 2017, studies by Young and colleagues found evidence to suggest that neurofeedback can significantly decrease depressive symptoms by increasing activity surrounding positive memories. The study suggests a strong correlation between the role of the amygdala in the recovery of depression.

Recent research in 2016 by Wang and colleagues investigated the efficacy of neurofeedback on alpha asymmetry in patients with major depressive disorder. Patients were randomly assigned to either a neurofeedback training group or control group. Over 6 weeks, the people in the neurofeedback group received training for 1 hour each week. The training saw those who responded to the neurofeedback training decrease their scores in both depression and anxiety when comparing pre and post measures. The findings highlight the benefits of neurofeedback on left and right frontal activity asymmetry in patients with major depressive disorder. One suggestion for non-responders to treatment in the neurofeedback group, was that the patients may have needed more sessions of training. Appropriate clinical application can be drawn from those who responded to treatment in the neurofeedback group.

In 2016, Cheon, Koo and Choi, evaluated the effect of neurofeedback on depressive symptoms and electrophysiological disturbances in patients with major depressive disorder. Twenty participants suffering from depression were recruited to participate in an 8-week, prospective, open-label study, to assess the efficacy of left prefrontal beta with alpha/theta training. The treatment protocol was twice or three times a week training of beta at F3 with alpha/theta at Pz for 8 weeks. It was found that depressive symptoms improved significantly (as determined by scores on self-report questionnaires) after neurofeedback treatment. Despite some limitations, such as, small sample size and lack of a control group for comparison, this study indicates that neurofeedback may have significant effects in patients with major depressive disorder.

In 2016,  Kaur and Singh from Punjab University focused their research on spectral analysis of EEG signals for tomographic neurofeedback. Score standardised low resolution electromagnetic tomography (sLORETA) was applied over 16 sessions to a patient with depression. The research found that sLORETA neurofeedback training increased alpha, impacted the theta/beta ratio and decreased beta in a patient with depression, suggesting tomographic neurofeedback could have a positive effect on depressive symptoms.

In 2015, Ramirez and colleagues introduced a new approach using neurofeedback. The approach focused on alleviating depression in elderly populations and required participants to manipulate expressive parameters in musical performances. The researchers found that musical neurofeedback training led to decreased depressive symptoms and decreased alpha activity in the frontal lobe in elderly individuals. Differences between pre and post BDI depression scores were found to be significant suggesting a positive effect of neurofeedback treatment on depressive symptoms in this population group.

Cheon and colleagues in 2015 carried out naturalistic study in a clinical setting to investigate the effects of neurofeedback on adult psychiatric patients. Seventy-seven patients were involved in the study. The neurofeedback protocol was adjusted according to each patient’s individual psychiatric complaints and the most common disorder was depression among other psychiatric complaints such as anxiety. For patients with depression, adjusting abnormal frontal cortex asymmetery between the left and right hemisphere was important in reducing depressive symptoms regardless of the specific neurofeedback protocol method prescribed for each participant. The findings showed that neurofeedback was successful in alleviating clinical symptoms of psychiatric disorders such as depression.

In 2015, Mirski and colleagues (from various institutions in Poland, USA, Russia and Norway), proposed to investigate the efficacy of an individually tailored neurofeedback protocol using anodal tDCs/ neurofeedback. A 45 year old female patient had previously undergone an operation of the meningioma, and complained of pain, anxiety, trouble sleeping, inattention and had withdrawn from work. Neuropsychological testing revealed this patient had post-operative depression. The research aimed to assess this tailored neurofeedback treatment protocol efficacy on post-operative depression. The research found that the patient was able to recover from her post-operative depression and returned to work following 20 sessions of the combined neurofeedback/DCS protocol.

In 2014, Young and associates found that real-time fMRI neurofeedback training of amygdala activity in individuals with major depression led to an improved ability to self-regulate the amygdala response. Participants in the experimental condition were able to up-regulate their amygdala response during positive memory recall. Pre and post scans showed significant increases of happiness ratings and significant decreases of anxiety ratings when compared to control group results. The results showed an improvement in mood and promising implications for fMRI neurofeedback training as a therapeutic application in the treatment of major depressive disorder.

In a controlled trial conducted by Escolano and colleagues in 2014, participants were allocated to either a neurofeedback test group or control group. This study was aimed at investigating a neurofeedback intervention on working-memory function in depressed patients. The protocol employed was targeted to increase the upper alpha power of the parieto-occipital area of the scalp. The neurofeedback test group participated in 8 training sessions and the results compared to the non-intervention control group. Cognitive variables including working memory, attention and executive function were measured pre and post training. The test group receiving the neurofeedback training showed improvement in performance as well as processing speed in working memory functioning. Enhanced upper alpha power was also observed in patients following neurofeedback training. A positive correlation was reported between improvement in processing speed and beta power increase. The results are supportive of this neurofeedback treatment protocol for working memory function in depressed patients.

In 2014, Lucas Koberda from Tellahassee Neurobalance Center (in USA) found that LORETA Z-score neurofeedback training led to improvements in depressive symptoms in individuals diagnosed with depression. Two cases were presented, one at 15 years of age and the second 40 years. The younger participant presented with anxiety, palpitations and dysregulation of the AC subcallosal region showing an increase in beta activity. After 15 sessions of neurofeedback therapy this dysregulation was corrected. In the second case, the patient has sustained memory impairment due to depresssion and had not been responding to conventional treatments. After 10 sessions of neurofeedback this patient was able to show improvement in cognitive domains particularly memory, information processing speed and visual spacial domain. Successful neurofeedback treatment also enabled this patient to return to work after a significant period of unemployment.

In 2014, Choobforoushzadeh and colleagues conducted a randomised trial on 24 Multiple Sclerosis patients showing symptoms of fatigue and depression. Patients were randomly allocated to two treatment groups; a neurofeedback treatment that underwent 16 sessions of training or a normal treatment group. Evaluations were measured at baseline, end of trials and at 2 month follow-up, differences in scores between the groups were examined. Using the Hospital Anxiety and Depression Scale for the outcome measures of depression, the study found that neurofeedback reduced symptoms of depression in patients with MS, compared to the standard treatment. These effects were maintained at the 2-month follow-up. These findings suggest that neurofeedback can aid in the treatment of depression in a variety of disorders and conditions.

A pilot study carried out by Choi and colleagues in 2011, found that asymmetry neurofeedback training increased left frontal dominance which led to the alleviation of depressive symptoms in individuals with depression. The neurofeedback training was shown to have profound effect upon emotion and cognition. Following treatment cognitive tests revealed improved performance in executive functioning when compared to placebo group which showed no such improvement. This demonstrates the impact of neurofeedback on underlying physiological asymmetry associated with depression which can improve depressive symptoms and cognition. The findings have been consistent with previous research.

A paper published in 2005(a) by D. Croydon Hammond outlines the internal meachanisms in why asymmetry has been associated with depression and how neurofeedback has an affect on depressive symptoms through this brain mechanism. It is noted that the left hemisphere of the prefrontal cortex is associated with an advantage for positive emotion and the right negative emotion. In depression there has been observed an impairment in the left prefrontal function, this imbalance can implicate a vulnerability to depression Hammond writes. In a second research paper from Hammond in 2005(b) focused on the biological aspects of depression, findings showed that neurofeedback is as effective (if not more) than regular medications in the reduction of depressive symptoms. The study further showed that the benefit of neurofeedback are more long-lasting than those of medication. This approach to treatment in depression has been highlighted as a noninvasive intervention and is not associated with major side effects related to other treatments such as medication.

Using the Roshi, a double channel unit integrating neurofeedback and photic stimulation treatment, D. Croydon Hammond in the year 2000 reported a reduction in depressive symptoms including somatic symptoms, anxiety and rumination. The treatment targeted left hemisphere beta training in a individual with severe medication resistant depression. The patient underwent 30 sessions of training. After the first five sessions the patient reported feeling less depressed and at the end of the full treatment, objective measures confirmed the significant improvements in depression and related symptoms. Benefits evident in the patient showed they had become more active, more socially involved and less withdrawn and these were maintained at eight and half month follow-up.

In a single case study Carolyn Earnest in 1999, presented findings of the first account of neurofeedback efficacy for depression on an adolescent. She (the patient) was diagnosed with a single episode of chronic depressive disorder at the age of 14. This patient received 67 episodes of neurofeedback training over a 10 month period. The protocol used was an asymmetry protocol to increase the activation in the left hemisphere and decrease activation in the right hemisphere and was carried out alongside psychotherapy sessions. Positive results were observed in the patient’s progress through the treatment and learned to increase differences in right and left hemisphere activation. The assessment of depression using The Beck Depression Inventory scores showed a significant decrease from 11 at the beginning of the neurofeedback training to 3 at the end of the trial. The findings of the study attributed these positive findings to the neurofeedback training. Interestingly, the psychotherapist involved in this case reported that the neurofeedback training prevented further mental illness in the individual. This case outlines the potential benefit of neurofeedback for depression in adolescents as well as adults.

Baehr, Rosenfeld and Baehr in 1997 presented two case studies of depressed women who each received more than 34 sessions of neurofeedback training. The researches applied an alpha asymmetry protocol. They wanted to find out if the patients could learn to increase the activity of the left frontal hemisphere or decrease right side activation in order to reduce their depression. The first patient in these case studies was able the differences in right and left frontal brain activation. After twenty-five sessions of alpha asymmetry neurofeedback training this patient claimed to no longer feel depressed and could identify different emotions evoked by depression and those normal to worry or sadness associated with adverse life events. A retest at five month follow-up showed that she had continued to maintain the learnt asymmetry differences. Similar to the first patient, the second patient also achieved the ability to distinguish between right and left hemisphere activation. She made significant gains in her functioning. In both cases neither medication or psychotherapy had been effective at helping them overcome their depression until a neurofeedback protocol had been added to their treatment.

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