Electroconvulsive Therapy Credentialing for Psychiatrists-Review of Required Standards Across States and Territories in Australia.

ABSTRACT: Electroconvulsive therapy (ECT) is a complex medical procedure, the delivery of which requires specialist knowledge and skills. We reviewed the standards required for ECT credentialing in different jurisdictions in Australia. We reviewed the Chief Psychiatrist guidelines and statewide policy standards on ECT and focused on standards required for initial credentialing and ongoing privileging in ECT. We compared the credentialing requirements within these documents with the standards specified in the Royal Australian and New Zealand College of Psychiatrists professional practice guideline for ECT. Most of the jurisdictions had specific standards for initial credentialing and maintenance of this credentialing; however, there was significant variance in the credentialing process and standards required. It would be useful to have a minimum standard for credentialing for ECT psychiatrists and prescribers. This standard would be relevant for practice of ECT internationally. States and territories would have the responsibility for implementation of these standards. Appropriate training and establishing good clinical governance processes are essential to the provision of high quality ECT.

Obsessive-compulsive disorder (OCD) is associated with increased engagement of frontal brain regions across multiple event-related potentials.

BACKGROUND: Obsessive-compulsive disorder (OCD) is a psychiatric condition leading to significant distress and poor quality of life. Successful treatment of OCD is restricted by the limited knowledge about its pathophysiology. This study aimed to investigate the pathophysiology of OCD using electroencephalographic (EEG) event-related potentials (ERPs), elicited from multiple tasks to characterise disorder-related differences in underlying brain activity across multiple neural processes. METHODS: ERP data were obtained from 25 OCD patients and 27 age- and sex-matched healthy controls (HCs) by recording EEG during flanker and go/nogo tasks. Error-related negativity (ERN) was elicited by the flanker task, while N200 and P300 were generated using the go/nogo task. Primary comparisons of the neural response amplitudes and the topographical distribution of neural activity were conducted using scalp field differences across all time points and electrodes. RESULTS: Compared to HCs, the OCD group showed altered ERP distributions. Contrasting with the previous literature on ERN and N200 topographies in OCD where fronto-central negative voltages were reported, we detected positive voltages. Additionally, the P300 was found to be less negative in the frontal regions. None of these ERP findings were associated with OCD symptom severity. CONCLUSIONS: These results indicate that individuals with OCD show altered frontal neural activity across multiple executive function-related processes, supporting the frontal dysfunction theory of OCD. Furthermore, due to the lack of association between altered ERPs and OCD symptom severity, they may be considered potential candidate endophenotypes for OCD.

Prescribing electroconvulsive therapy for depression: Not as simple as it used to be.

In the last century, prescribing electroconvulsive therapy usually involved considering the relative merits of unilateral versus bilateral electroconvulsive therapy, with most other parameters fixed. However, research over the last 30 years has discovered that several parameters of the electroconvulsive therapy stimulus can have a significant impact on efficacy and cognitive side effects. The stimulus dose relative to seizure threshold was shown to significantly affect efficacy, especially for right unilateral electroconvulsive therapy, where suprathreshold doses in the vicinity of 5-6 times seizure threshold were far more efficacious than doses closer to threshold. However, this did not hold for bitemporal electroconvulsive therapy, where near-threshold stimuli were equally effective as suprathreshold stimuli. Then, changes in stimulus pulse width were found to also have a significant impact on both efficacy and side effects, with ultrabrief pulse widths of 0.3 ms having significantly fewer cognitive side effects in unilateral electroconvulsive therapy than standard brief pulse widths of 1.0 ms, with only slightly reduced efficacy. Therefore, choosing the optimum electroconvulsive therapy prescription for an individual patient now requires consideration of placement, pulse width and stimulus dose relative to seizure threshold, and how these three interact with each other. This viewpoint aims to raise awareness of these issues for psychiatrists involved in electroconvulsive therapy practice.

The prescription of psychedelic therapies in Australia and New Zealand: A brief survey of psychiatrists.

OBJECTIVE: To explore the knowledge and attitudes of psychiatrists about psychedelics therapies. METHOD: Access to a cross-sectional survey was distributed to psychiatrists through social media channels. Attitudes and knowledge about psychedelic therapies were recorded using Likert scales and ranking questions. RESULTS: Fifty-eight complete responses were collected (44 fully trained +14 trainee RANZCP members). Greater than 85% of respondents agreed there is a shortfall in effective psychiatric treatments, and greater than 65% agreed that psychedelic therapies might address this shortfall. The psychiatrists did not consider themselves knowledgeable about psychedelic therapies, with 60% showing interest in further training on this topic. About 70% of the sample hold various concerns about psychedelic therapies, and more believe that the prescription of psychedelics should be limited to psychiatrists in the future. CONCLUSION: Considering these results in the context of a rapidly changing landscape relating to psychedelic research and regulations, we suggest there is scope to develop up-to-date education about psychedelics for psychiatrists.

Effects of aspirin on the long-term management of depression in older people: a double-blind randomised placebo-controlled trial.

Late-life depression is common and often inadequately managed using existing therapies. Depression is also associated with increased markers of inflammation, suggesting a potential role for anti-inflammatory agents. ASPREE-D is a sub-study of ASPREE, a large multi-centre, population-based, double-blind, placebo-controlled trial of aspirin vs placebo in older Australian and American adults (median follow-up: 4.7 years) of whom 1879 were depressed at baseline. Participants were given 100 mg daily dose of aspirin or placebo. Depressive symptoms were assessed annually using the validated, self-rated short version of the Center for Epidemiological Studies Depression scale. There was a significant increase in depressive scores (0.6; 95% CI 0.2 to 0.9; χ2 (1) = 10.37; p = 0.001) and a decreased score in the mental health component of a quality of life scale (-0.7; 95% CI -1.4 to -0.1; χ2 (1) = 4.74; p = 0.029) in the aspirin group compared to the placebo group. These effects were greater in the first year of follow-up and persisted throughout the study, albeit with small to very small effect sizes. This study failed to demonstrate any benefit of aspirin in the long-term course of depression in this community-dwelling sample of older adults over a 5-year period, and identified an adverse effect of aspirin in the course of depression in those with pre-existing depressive symptoms.

Anomalies in global network connectivity associated with early recovery from alcohol dependence: A network transcranial magnetic stimulation and electroencephalography study.

Although previous research in alcohol dependent populations identified alterations within local structures of the addiction 'reward' circuitry, there is limited research into global features of this network, especially in early recovery. Transcranial magnetic stimulation (TMS) is capable of non-invasively perturbing the brain network while electroencephalography (EEG) measures the network response. The current study is the first to apply a TMS inhibitory paradigm while utilising network science (graph theory) to quantify network anomalies associated with alcohol dependence. Eleven individuals with alcohol-dependence (ALD) in early recovery and 16 healthy controls (HC) were administered 75 single pulses and 75 paired-pulses (inhibitory paradigm) to both the left and right prefrontal cortex (PFC). For each participant, Pearson cross-correlation was applied to the EEG data and correlation matrices constructed. Global network measures (mean degree, clustering coefficient, local efficiency and global efficiency) were extracted for comparison between groups. Following administration of the inhibitory paired-pulse TMS to the left PFC, the ALD group exhibited altered mean degree, clustering coefficient, local efficiency and global efficiency compared to HC. Decreases in local efficiency increased the prediction of being in the ALD group, while all network metrics (following paired-pulse left TMS) were able to adequately discriminate between the groups. In the ALD group, reduced mean degree and global clustering was associated with increased severity of past alcohol use. Our study provides preliminary evidence of altered network topology in patients with alcohol dependence in early recovery. Network anomalies were predictive of high alcohol use and correlated with clinical features of alcohol dependence. Further research using this novel brain mapping technique may identify useful network biomarkers of alcohol dependence and recovery.

The evidence is in: Repetitive transcranial magnetic stimulation is an effective, safe and well-tolerated treatment for patients with major depressive disorder.

Despite more than 25 years of research establishing the antidepressant efficacy of repetitive transcranial magnetic stimulation, there remains uncertainty about the depth and breadth of this evidence base, resulting in confusion as to where repetitive transcranial magnetic stimulation fits in the therapeutic armamentarium in the management of patients with mood disorders. The purpose of this article is to provide a concise description of the evidence base supporting the use of repetitive transcranial magnetic stimulation in the context of the stages of research that typically accompanies the development of evidence for a new therapy. The antidepressant efficacy for the use of repetitive transcranial magnetic stimulation in the treatment of depression has been established through a relatively traditional pathway beginning with small case series, progressing to single-site clinical trials and then to larger multisite randomised double-blind controlled trials. Antidepressant effects have been confirmed in numerous meta-analyses followed more recently by large network meta-analysis and umbrella reviews, with evidence that repetitive transcranial magnetic stimulation may have greater efficacy than alternatives for patients with treatment-resistant depression. Finally, repetitive transcranial magnetic stimulation has been shown to produce meaningful response and remission rates in real-world samples of greater than 5000 patients. The evidence for the antidepressant efficacy of repetitive transcranial magnetic stimulation therapy is overwhelming, and it should be considered a routine part of clinical care wherever available.

Revisiting the effectiveness of repetitive transcranial magnetic stimulation treatment in depression, again.

Following on from the publication of the Royal Australian and New Zealand Journal of Psychiatry Mood Disorder Clinical Practice Guidelines (2020) and criticisms of how these aberrantly addressed repetitive transcranial magnetic stimulation treatment of depression, questions have continued to be raised in the journal about this treatment by a small group of authors, whose views we contend do not reflect the broad acceptance of this treatment nationally and internationally. In fact, the evidence supporting the use of repetitive transcranial magnetic stimulation treatment in depression is unambiguous and substantial, consisting of an extensive series of clinical trials supported by multiple meta-analyses, network meta-analysis and umbrella reviews. Importantly, the use of repetitive transcranial magnetic stimulation treatment in depression has also been subject to a series of health economic analyses. These indicate that repetitive transcranial magnetic stimulation is a cost-effective therapy and have been used in some jurisdictions, including Australia, in support of public funding. An argument has been made that offering repetitive transcranial magnetic stimulation treatment may delay potentially effective pharmacotherapy. In fact, there is considerably greater danger of the opposite happening. Repetitive transcranial magnetic stimulation is as, if not more effective, than antidepressant medication after two unsuccessful medication trials and should be a consideration for all patients under these circumstances where available. There is no meaningful ongoing debate about the use of repetitive transcranial magnetic stimulation treatment in depression - it is a safe, effective and cost-effective treatment.

Personalized connectivity-guided DLPFC-TMS for depression: Advancing computational feasibility, precision and reproducibility.

Repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (DLPFC) is an established treatment for refractory depression, however, therapeutic outcomes vary. Mounting evidence suggests that clinical response relates to functional connectivity with the subgenual cingulate cortex (SGC) at the precise DLPFC stimulation site. Critically, SGC-related network architecture shows considerable interindividual variation across the spatial extent of the DLPFC, indicating that connectivity-based target personalization could potentially be necessary to improve treatment outcomes. However, to date accurate personalization has not appeared feasible, with recent work indicating that the intraindividual reproducibility of optimal targets is limited to 3.5 cm. Here we developed reliable and accurate methodologies to compute individualized connectivity-guided stimulation targets. In resting-state functional MRI scans acquired across 1,000 healthy adults, we demonstrate that, using this approach, personalized targets can be reliably and robustly pinpointed, with a median accuracy of ~2 mm between scans repeated across separate days. These targets remained highly stable, even after 1 year, with a median intraindividual distance between coordinates of only 2.7 mm. Interindividual spatial variation in personalized targets exceeded intraindividual variation by a factor of up to 6.85, suggesting that personalized targets did not trivially converge to a group-average site. Moreover, personalized targets were heritable, suggesting that connectivity-guided rTMS personalization is stable over time and under genetic control. This computational framework provides capacity for personalized connectivity-guided TMS targets to be robustly computed with high precision and has the flexibly to advance research in other basic research and clinical applications.

A pilot study of magnetic seizure therapy for treatment-resistant obsessive-compulsive disorder.

BACKGROUND: There is growing interest in the potential of neuromodulation options in treatment-resistant obsessive-compulsive disorder (OCD). Magnetic seizure therapy (MST), is a new treatment intervention in which generalized seizures are induced with transcranial magnetic stimulation. We conducted a pilot study to assess the efficacy and cognitive effects of MST in patients with treatment-resistant OCD. METHODS: In an open-label pilot study, participants with treatment-resistant OCD and a baseline Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores of ≥16 were treated with up to 24 acute treatments. The primary clinical outcomes were clinical response (Y-BOCS score reduction ≥30%) and remission (final Y-BOCS score ≤8). A neurocognitive battery, the Quick Inventory for Depressive Symptoms-Self Report (QIDS-SR), the Beck Scale for Suicidal Ideation (SSI), and the Quality of Life Enjoyment and Satisfaction Questionnaire-Short Form (Q-LES-Q-SF) were also completed as secondary measures. RESULTS: Ten participants with OCD who had not responded to medications or psychotherapy enrolled in the study and seven completed an adequate trial (defined as ≥8 treatments). MST was associated with minimal cognitive effects except for some decrease in autobiographical memory and no serious adverse effects. Only one participant met the predefined criteria for response, and none for remission. The baseline and endpoint Y-BOCS scores were not statistically different. CONCLUSION: Overall, MST was not beneficial in a small group of patients with treatment-resistant OCD. At this time, other studies of MST for OCD are not warranted until different coil placements targeting other brain circuits can be proposed.

The place of non-invasive brain stimulation in the RANZCP clinical practice guidelines for mood disorders.

Clinical practice guidelines are important documents as they have the capacity to significantly influence and shape clinical practice in important areas of therapeutics. As such, they need to be developed informed by comprehensive and quality-based systematic reviews, involve consensus deliberations representative of the appropriate experts in the field and be subject to thorough critical review. A revised clinical practice guideline for the management of patients with mood disorders was recently published under the auspices of the Royal Australian and New Zealand College of Psychiatrists. However, this clinical practice guideline was not developed in a manner that reflects the appropriate standards that should apply to clinical practice guideline development and it has critical flaws, especially as it pertains to the use of repetitive transcranial magnetic stimulation treatment for patients with depression. The revision of the college clinical practice guideline has explicitly removed clear and unequivocal evidence-based recommendations that were found in a previous version of the clinical practice guideline and replaced these with consensus-based recommendations. However, the consensus-based recommendations were developed without consultation of the appropriate expert body within the college and contradict the scientific literature. There is substantive and unequivocal evidence supporting the antidepressant use of repetitive transcranial magnetic stimulation in the treatment of patients with depression and its use after a patient with depression has failed a limited number (typically around two) of antidepressant medication trials. Readers should refer to the college Professional Practice Guidelines for repetitive transcranial magnetic stimulation published in 2018 for thorough information about the use of this important new treatment.

Mindfulness meditation alters neural activity underpinning working memory during tactile distraction.

Evidence suggests that mindfulness meditation (MM) improves selective attention and reduces distractibility by enhancing top-down neural modulation. Altered P300 and alpha neural activity from MM have been identified and may reflect the neural changes that underpin these improvements. Given the proposed role of alpha activity in supressing processing of task-irrelevant information, it is theorised that altered alpha activity may underlie increased availability of neural resources in meditators. The present study investigated attentional function in meditators using a cross-modal study design, examining the P300 during working memory (WM) and alpha activity during concurrent distracting tactile stimuli. Thirty-three meditators and 27 healthy controls participated in the study. Meditators showed a more frontal distribution of P300 neural activity following WM stimuli (p = 0.005, η2 = 0.060) and more modulation of alpha activity at parietal-occipital regions between single (tactile stimulation only) and dual task demands (tactile stimulation plus WM task) (p < 0.001, η2 = 0.065). Additionally, meditators performed more accurately than controls (p = 0.038, η2 = 0.067). The altered distribution of neural activity concurrent with improved WM performance suggests greater attentional resources dedicated to task related functions, such as WM in meditators. Thus, meditation-related neural changes are likely multifaceted, involving both altered distribution and also amplitudes of brain activity, thereby enhancing attentional processes depending on task requirements.

Magnetic seizure therapy is efficacious and well tolerated for treatment-resistant bipolar depression: an open-label clinical trial

Background: Treatment-resistant bipolar depression can be treated effectively using electroconvulsive therapy, but its use is limited because of stigma and cognitive adverse effects. Magnetic seizure therapy is a new convulsive therapy with promising early evidence of antidepressant effects and minimal cognitive adverse effects. However, there are no clinical trials of the efficacy and safety of magnetic seizure therapy for treatment-resistant bipolar depression. Methods: Participants with treatment-resistant bipolar depression were treated with magnetic seizure therapy for up to 24 sessions or until remission. Magnetic seizure therapy was applied over the prefrontal cortex at high (100 Hz; n = 8), medium (50 or 60 Hz; n = 9) or low (25 Hz; n = 3) frequency, or over the vertex at high frequency (n = 6). The primary outcome measure was the 24-item Hamilton Rating Scale for Depression. Participants completed a comprehensive battery of neurocognitive tests. Results: Twenty-six participants completed a minimally adequate trial of magnetic seizure therapy (i.e., ≥ 8 sessions), and 20 completed full treatment per protocol. Participants showed a significant reduction in scores on the Hamilton Rating Scale for Depression. Adequate trial completers had a remission rate of 23.1% and a response rate of 38.5%. Per-protocol completers had a remission rate of 30% and a response rate of 50%. Almost all cognitive measures remained stable, except for significantly worsened recall consistency on the autobiographical memory inventory. Limitations: The open-label study design and modest sample size did not allow for comparisons between stimulation parameters. Conclusion: In treatment-resistant bipolar depression, magnetic seizure therapy produced significant improvements in depression symptoms with minimal effects on cognitive performance. These promising results warrant further investigation with larger randomized clinical trials comparing magnetic seizure therapy to electroconvulsive therapy. Clinical trial registration: NCT01596608; clinicaltrials.gov

The dorsomedial prefrontal cortex as a flexible hub mediating behavioral as well as local and distributed neural effects of social support context on pain: A Theta Burst Stimulation and TMS-EEG study.

Increasing evidence points to an analgesic influence of social support context, in which the dorsomedial prefrontal cortex (dmPFC) may play a key role. Transcranial Magnetic Stimulation (TMS) has the capacity to causally modulate brain activity. This study was designed to investigate the potential role of dmPFC in orchestrating the behavioral and neural effects of social context during pain. Twenty-three healthy participants underwent a three-session cross-over, single-blinded, sham-controlled protocol in which they received Theta Burst Stimulation (TBS) (facilitatory intermittent TBS, suppressive continuous TBS, or Sham) delivered to the dmPFC. In each session, participants underwent cold pain while viewing an image of a romantic partner or a stranger. Effects of TBS to the dmPFC were assessed using a measure of pain perception, neural activity and network connectivity using electroencephalography (EEG) and TMS-EEG. In the stranger condition, pain experience increased following iTBS. This was associated with increased connectivity between central regions and fronto-parietal regions. In contrast, in the romantic partner condition, iTBS increased connectivity only between frontal and occipital regions and did not modulate pain experience. In line with recent studies, neither cTBS nor Sham stimulation elicited neural or behavioral changes. Together these findings suggest that the dmPFC has the capacity to causally modulate pain-related information integration and network configuration in a context-dependent manner.

A multivariate neuroimaging biomarker of individual outcome to transcranial magnetic stimulation in depression.

The neurobiology of major depressive disorder (MDD) remains incompletely understood, and many individuals fail to respond to standard treatments. Repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (DLPFC) has emerged as a promising antidepressant therapy. However, the heterogeneity of response underscores a pressing need for biomarkers of treatment outcome. We acquired resting state functional magnetic resonance imaging (rsfMRI) data in 47 MDD individuals prior to 5-8 weeks of rTMS treatment targeted using the F3 beam approach and in 29 healthy comparison subjects. The caudate, prefrontal cortex, and thalamus showed significantly lower blood oxygenation level-dependent (BOLD) signal power in MDD individuals at baseline. Critically, individuals who responded best to treatment were associated with lower pre-treatment BOLD power in these regions. Additionally, functional connectivity (FC) in the default mode and affective networks was associated with treatment response. We leveraged these findings to train support vector machines (SVMs) to predict individual treatment responses, based on learned patterns of baseline FC, BOLD signal power and clinical features. Treatment response (responder vs. nonresponder) was predicted with 85-95% accuracy. Reduction in symptoms was predicted to within a mean error of ±16% (r = .68, p < .001). These preliminary findings suggest that therapeutic outcome to DLPFC-rTMS could be predicted at a clinically meaningful level using only a small number of core neurobiological features of MDD, warranting prospective testing to ascertain generalizability. This provides a novel, transparent and physiologically plausible multivariate approach for classification of individual response to what has become the most commonly employed rTMS treatment worldwide. This study utilizes data from a larger clinical study (Australian New Zealand Clinical Trials Registry: Investigating Predictors of Response to Transcranial Magnetic Stimulation for the Treatment of Depression; ACTRN12610001071011; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=336262).

The effects of individualised intermittent theta burst stimulation in the prefrontal cortex: A TMS-EEG study.

Recent studies have highlighted variability in response to theta burst stimulation (TBS) in humans. TBS paradigm was originally developed in rodents to mimic gamma bursts coupled with theta rhythms, and was shown to elicit long-term potentiation. The protocol was subsequently adapted for humans using standardised frequencies of stimulation. However, each individual has different rhythmic firing pattern. The present study sought to explore whether individualised intermittent TBS (Ind iTBS) could outperform the effects of two other iTBS variants. Twenty healthy volunteers received iTBS over left prefrontal cortex using 30 Hz at 6 Hz, 50 Hz at 5 Hz, or individualised frequency in separate sessions. Ind iTBS was determined using theta-gamma coupling during the 3-back task. Concurrent use of transcranial magnetic stimulation and electroencephalography (TMS-EEG) was used to track changes in cortical plasticity. We also utilised mood ratings using a visual analogue scale and assessed working memory via the 3-back task before and after stimulation. No group-level effect was observed following either 30 or 50 Hz iTBS in TMS-EEG. Ind iTBS significantly increased the amplitude of the TMS-evoked P60, and decreased N100 and P200 amplitudes. A significant positive correlation between neurophysiological change and change in mood rating was also observed. Improved accuracy in the 3-back task was observed following both 50 Hz and Ind iTBS conditions. These findings highlight the critical importance of frequency in the parameter space of iTBS. Tailored stimulation parameters appear more efficacious than standard paradigms in neurophysiological and mood changes. This novel approach presents a promising option and benefits may extend to clinical applications.

Is rTMS effective for anxiety symptoms in major depressive disorder? An efficacy analysis comparing left-sided high-frequency, right-sided low-frequency, and sequential bilateral rTMS protocols.

BACKGROUND: Anxiety symptoms are common in major depressive disorder. Whilst therapeutic efficacy of repetitive transcranial magnetic stimulation (rTMS) in depression is well-established, minimal research has investigated rTMS's efficacy in treating anxiety symptoms in depression. METHODS: This study investigates the effectiveness of rTMS in treating anxiety symptoms in depression, specifically the relative efficacy of the three rTMS protocols commonly used in clinical practice: left-sided high-frequency, right-sided low-frequency and sequential bilateral rTMS. Antidepressant efficacy of each rTMS protocol is also investigated. Treatment data for 697 patients were pooled from three studies across five sites. Changes in Beck's Anxiety Inventory (BAI) and the Hamilton Depression Rating Scale over 4-week rTMS courses were analysed using latent growth curve modelling. RESULTS: All rTMS protocols were effective in treating anxiety symptoms (mean BAI reduction, 8.13 points; p < 0.001) and depressive symptoms. Near therapeutic equivalence was seen across the three protocols. Improvement in depressive severity positively correlated with improvement in anxiety. Both high- and low-baseline anxiety scores showed overall symptom reduction. CONCLUSIONS: This study addresses the clinical knowledge gap pertaining to rTMS's therapeutic efficacy in treating anxiety symptoms in depression and the relative efficacy of three commonly used stimulation protocols. Our findings suggest therapeutic equivalence across left-sided high-frequency, right-sided low-frequency, and sequential bilateral rTMS approaches.

Bipolar disorder in the balance.

Bipolar disorder (BD) is a severe mood disorder that lacks established electrophysiological, neuroimaging or biological markers to assist with both diagnosis and monitoring disease severity. This study's aim is to describe the potential of new neurophysiological features assistive in BD diagnosis and severity measurement utilizing the recording of electrical activity from the outer ear canal called Electrovestibulography (EVestG). From EVestG data sensory vestibulo-acoustic features were extracted from a single supine-vertical translation stimulus to distinguish 50 depressed and partly remitted/remitted bipolar disorder patients [18 symptomatic (BD-S, MADRS > 19), 32 reduced symptomatic (BD-R, MADRS ≤ 19)] and 31 age and gender matched healthy individuals (controls). Six features were extracted from the measured firing pattern interval histogram and the extracted shape of the average field potential response. Five of the six features had low but significant correlations (p < 0.05) with the MADRS assessment. Using leave-one-out-cross-validation, unbiased parametric and non-parametric classification routines resulted in 75-79%, 84-86%, 76-85% and 79-82% accuracy for separation of control from BD, BD-S and BD-R as well as BD-S from BD-R groups, respectively. The main limitation of this study was the inability to fully disentangle the impact of prescribed medication from the responses recorded. A mix of stationary and movement evoked EVestG features produced good discrimination between control and BD patients whether BD-S or BD-R. Moreover, BD-S and BD-R appear to have measurably different pathophysiological manifestations. The firing pattern features used were dissimilar to those observed in a prior major depressive disorder study.