Changes in Functional Connectivity Predict Outcome of Repetitive Transcranial Magnetic Stimulation Treatment of Major Depressive Disorder

Repetitive transcranial magnetic stimulation (rTMS) treatment of major depressive disorder (MDD) is associated with changes in brain functional connectivity (FC). These changes may be related to the mechanism of action of rTMS and explain the variability in clinical outcome. We examined changes in electroencephalographic FC during the first rTMS treatment in 109 subjects treated with 10 Hz stimulation to left dorsolateral prefrontal cortex. All subjects subsequently received 30 treatments and clinical response was defined as ≥40% improvement in the inventory of depressive symptomatology-30 SR score at treatment 30. Connectivity change was assessed with coherence, envelope correlation, and a novel measure, alpha spectral correlation (αSC). Machine learning was used to develop predictive models of outcome for each connectivity measure, which were compared with prediction based upon early clinical improvement. Significant connectivity changes were associated with clinical outcome (P < 0.001). Machine learning models based on αSC yielded the most accurate prediction (area under the curve, AUC = 0.83), and performance improved when combined with early clinical improvement measures (AUC = 0.91). The initial rTMS treatment session produced robust changes in FC, which were significant predictors of clinical outcome of a full course of treatment for MDD.

EEG Spectral Features in Sleep of Autism Spectrum Disorders in Children with Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is a multisystem disorder with increased prevalence of autism spectrum disorders (ASDs). This project aimed to characterize the autism phenotype of TSC and identify biomarkers of risk for ASD. Because abnormalities of EEG during sleep are tied to neurodevelopment in children, we compared electroencephalographic (EEG) measures during Stage II sleep in TSC children who either did (ASD+) or did not (ASD-) exhibit symptoms of ASD over 36-month follow up. Relative alpha band power was significantly elevated in the ASD+ group at 24 months of age with smaller differences at younger ages, suggesting this may arise from differences in brain development. These findings suggest that EEG features could enhance the detection of risk for ASD.

Dorsolateral prefrontal γ-aminobutyric acid in patients with treatment-resistant depression after transcranial magnetic stimulation measured with magnetic resonance spectroscopy

BACKGROUND

The therapeutic mechanism of repetitive transcranial magnetic stimulation (rTMS) for treatment-resistant depression (TRD) may involve modulation of γ-aminobutyric acid (GABA) levels. We used proton magnetic resonance spectroscopy (MRS) to assess changes in GABA levels at the site of rTMS in the left dorsolateral prefrontal cortex (DLPFC).

METHODS

In 26 adults with TRD, we used Mescher–Garwood point-resolved spectroscopy (MEGA-PRESS) spectral-editing MRS to measure GABA in the left DLPFC before and after standard clinical treatment with rTMS. All participants but 1 were medicated, including 12 patients on GABA agonist agents.

RESULTS

Mean GABA in the DLPFC increased 10.0% (p = 0.017) post-rTMS in the overall sample. As well, GABA increased significantly in rTMS responders (n = 12; 23.6%, p = 0.015) but not in nonresponders (n = 14; 4.1%, p = not significant). Changes in GABA were not significantly affected by GABAergic agonists, but clinical response was less frequent (p = 0.005) and weaker (p = 0.035) in the 12 participants who were receiving GABA agonists concomitant with rTMS treatment.

LIMITATIONS

This study had an open-label design in a population receiving naturalistic treatment.

CONCLUSION

Treatment using rTMS was associated with increases in GABA levels at the stimulation site in the left DLPFC, and the degree of GABA change was related to clinical improvement. Participants receiving concomitant treatment with a GABA agonist were less likely to respond to rTMS. These findings were consistent with earlier studies showing the effects of rTMS on GABA levels and support a GABAergic model of depression.

Time Course of Changes in Peripheral Blood Gene Expression During Medication Treatment for Major Depressive Disorder

Changes in gene expression (GE) during antidepressant treatment may increase understanding of the action of antidepressant medications and serve as biomarkers of efficacy. GE changes in peripheral blood are desirable because they can be assessed easily on multiple occasions during treatment. We report here on GE changes in 68 individuals who were treated for 8 weeks with either escitalopram alone, or escitalopram followed by bupropion. GE changes were assessed after 1, 2, and 8 weeks of treatment, with significant changes observed in 156, 121, and 585 peripheral blood gene transcripts, respectively. Thirty-one transcript changes were shared between the 1- and 8-week time points (seven upregulated, 24 downregulated). Differences were detected between the escitalopram- and bupropion-treated subjects, although there was no significant association between GE changes and clinical outcome. A subset of 18 genes overlapped with those previously identified as differentially expressed in subjects with MDD compared with healthy control subjects. There was statistically significant overlap between genes differentially expressed in the current and previous studies, with 10 genes overlapping in at least two previous studies. There was no enrichment for genes overexpressed in nervous system cell types, but there was a trend toward enrichment for genes in the WNT/β-catenin pathway in the anterior thalamus; three genes in this pathway showed differential expression in the present and in three previous studies. Our dataset and other similar studies will provide an important source of information about potential biomarkers of recovery and for potential dysregulation of GE in MDD.

Concomitant medication use and clinical outcome of repetitive Transcranial Magnetic Stimulation (rTMS) treatment of Major Depressive Disorder

BACKGROUND

Repetitive Transcranial Magnetic Stimulation (rTMS) is commonly administered to Major Depressive Disorder (MDD) patients taking psychotropic medications, yet the effects on treatment outcomes remain unknown. We explored how concomitant medication use relates to clinical response to a standard course of rTMS.

METHODS

Medications were tabulated for 181 MDD patients who underwent a six-week rTMS treatment course. All patients received 10 Hz rTMS administered to left dorsolateral prefrontal cortex (DLPFC), with 1 Hz administered to right DLPFC in patients with inadequate response to and/or intolerance of left-sided stimulation. Primary outcomes were change in Inventory of Depressive Symptomatology Self Report (IDS-SR30) total score after 2, 4, and 6 weeks.

RESULTS

Use of benzodiazepines was associated with less improvement at week 2, whereas use of psychostimulants was associated with greater improvement at week 2 and across 6 weeks. These effects were significant controlling for baseline variables including age, overall symptom severity, and severity of anxiety symptoms. Response rates at week 6 were lower in benzodiazepine users versus non-users (16.4% vs. 35.5%, p = 0.008), and higher in psychostimulant users versus non-users (39.2% vs. 22.0%, p = 0.02).

CONCLUSIONS

Concomitant medication use may impact rTMS treatment outcome. While the differences reported here could be considered clinically significant, results were not corrected for multiple comparisons and findings should be replicated before clinicians incorporate the evidence into clinical practice. Prospective, hypothesis-based treatment studies will aid in determining causal relationships between medication treatments and outcome.

Double-Blind, Sham-Controlled, Pilot Study of Trigeminal Nerve Stimulation for Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

Trigeminal nerve stimulation (TNS), a minimal-risk noninvasive neuromodulation method, showed potential benefits for attention-deficit/hyperactivity disorder (ADHD) in an unblinded open study. The present blinded sham-controlled trial was conducted to assess the efficacy and safety of TNS for ADHD and potential changes in brain spectral power using resting-state quantitative electroencephalography.

METHOD

Sixty-two children 8 to 12 years old, with full-scale IQ of at least 85 and Schedule for Affective Disorders and Schizophrenia-diagnosed ADHD, were randomized to 4 weeks of nightly treatment with active or sham TNS, followed by 1 week without intervention. Assessments included weekly clinician-administered ADHD Rating Scales (ADHD-RS) and Clinical Global Impression (CGI) scales and quantitative electroencephalography at baseline and week 4.

RESULTS

ADHD-RS total scores showed significant group-by-time interactions (F1,228 = 8.12, p = .005; week 4 Cohen d = 0.5). CGI-Improvement scores also favored active treatment (χ21,168 = 8.75, p = .003; number needed to treat = 3). Resting-state quantitative electroencephalography showed increased spectral power in the right frontal and frontal midline frequency bands with active TNS. Neither group had clinically meaningful adverse events.

CONCLUSION

This study demonstrates TNS efficacy for ADHD in a blinded sham-controlled trial, with estimated treatment effect size similar to non-stimulants. TNS is well tolerated and has minimal risk. Additional research should examine treatment response durability and potential impact on brain development with sustained use.

CLINICAL TRIAL REGISTRATION INFORMATION

Trigeminal Nerve Stimulation for ADHD; http://clinicaltrials.gov/; NCT02155608.

Predictors of response to synchronized transcranial magnetic stimulation for major depressive disorder

BACKGROUND

Synchronized transcranial magnetic stimulation (sTMS) is a new modality to reduce symptoms of major depressive disorder (MDD). sTMS uses rotating neodymium magnets to deliver low-field stimulation matched to the individual alpha frequency (IAF). A previous multisite study showed that sTMS significantly reduced MDD symptoms in the per-protocol sample. To this end, we evaluated clinical features associated with optimal sTMS outcomes.

METHODS

Using the per-protocol sample (n = 120) from the parent sham-controlled trial, we performed univariate and stepwise linear regression to identify predictors of response after 6 weeks of sTMS. A subsample (n = 83) that entered a 4-week open/active continuation phase also was examined. Candidate variables included age, sex, comorbid anxiety, number of failed antidepressants in the current depressive episode, MDD severity (17-item Hamilton Depression Rating Scale; HAMD17), anxiety symptom severity (HAMD17 anxiety/somatization factor), and IAF.

RESULTS

We found that greater baseline depressive (p < 0.001) and anxiety (p < 0.001) symptom severity were associated with better response to active sTMS, whereas fewer failed antidepressant trials predicted superior response to sham (p < 0.001). MDD severity and antidepressant resistance predicted outcomes in open/active phase sTMS; lower IAF predicted poorer response in participants who received 10 weeks of active sTMS (p = 0.001).

CONCLUSIONS

Participants with greater severity of depression and higher anxiety had superior responses to active sTMS, whereas treatment naïve individuals exhibited a greater response to sham. These results lend support to the primary efficacy findings, and support further investigation of sTMS as a therapeutic noninvasive brain stimulation modality.

Hypnotic Discontinuation Using a Blinded (Masked) Tapering Approach: A Case Series

Chronic use of hypnotic medications such as benzodiazepines is associated with adverse consequences including increased risk of falls. Efforts to help patients discontinue these medications have had varying levels of success. We developed a blinded (masked) tapering protocol to help patients taper off hypnotics. In this blinded protocol, patients consented to a drug taper but agreed to forego knowledge about the specific tapering schedule or the actual dose each night until the end of the taper. Blinded tapering aims to reduce negative expectancies for withdrawal effects that may impair a patient's successful discontinuation of hypnotics. In preparation for a randomized trial, we tested the feasibility of adding a blinded tapering component to current best evidence practice [supervised hypnotic taper combined with cognitive behavioral therapy for insomnia (CBTI)] in 5 adult patients recruited from an outpatient mental health practice in Oregon. A compounding pharmacy prepared the blinded capsules for each patient. During the gradual blinded taper, each participant completed CBTI. Measures collected included feasibility/process (e.g., recruitment barriers), hypnotic use, the Dysfunctional Beliefs and Attitudes about Sleep Scale, Insomnia Severity Index, Epworth Sleepiness Scale, and Patient Health Questionnaire-9 (depressive symptoms). The intervention was feasible, and participants reported high satisfaction with the protocol and willingness to follow the same treatment again. All five participants successfully discontinued their hypnotic medication use post-treatment. Dysfunctional beliefs/attitudes about sleep and insomnia severity improved. Blinded tapering is a promising new method for improving hypnotic discontinuation among patients treated with a combination of hypnotic tapering plus CBTI.

Change in Quantitative EEG Theta Cordance as a Potential Predictor of Repetitive Transcranial Magnetic Stimulation Clinical Outcome in Major Depressive Disorder

Repetitive transcranial magnetic stimulation (rTMS) has demonstrated efficacy in major depressive disorder (MDD), although clinical outcome is variable. Change in the resting-state quantitative electroencephalogram (qEEG), particularly in theta cordance early in the course of treatment, has been linked to antidepressant medication outcomes but has not been examined extensively in clinical rTMS. This study examined change in theta cordance over the first week of clinical rTMS and sought to identify a biomarker that would predict outcome at the end of 6 weeks of treatment. Clinically stable outpatients (n = 18) received nonblinded rTMS treatment administered to the dorsolateral prefrontal cortex (DLPFC). Treatment parameters (site, intensity, number of pulses) were adjusted on an ongoing basis guided by changes in symptom severity rating scale scores. qEEGs were recorded at pretreatment baseline and after 1 week of left DLPFC (L-DLPFC) rTMS using a 21-channel dry-electrode headset. Analyses examined the association between week 1 regional changes in theta band (4-8 Hz) cordance, and week 6 patient- and physician-rated outcomes. Theta cordance change in the central brain region predicted percent change in Inventory of Depressive Symptomology-Self-Report (IDS-SR) score, and improvement versus nonimprovement on the Clinical Global Impression-Improvement Inventory (CGI-I) ( R² = .38, P = .007; and Nagelkerke R² = .78, P = .0001, respectively). The cordance biomarker remained significant when controlling for age, gender, and baseline severity. Treatment-emergent change in EEG theta cordance in the first week of rTMS may predict acute (6-week) treatment outcome in MDD. This oscillatory synchrony biomarker merits further study in independent samples.

Benefits and Harms of Cranial Electrical Stimulation for Chronic Painful Conditions, Depression, Anxiety, and Insomnia: A Systematic Review

BACKGROUND

Cranial electrical stimulation (CES) is increasingly popular as a treatment, yet its clinical benefit is unclear.

PURPOSE

To review evidence about the benefits and harms of CES for adult patients with chronic painful conditions, depression, anxiety, and insomnia.

DATA SOURCES

Several databases from inception to 10 October 2017 without language restrictions and references from experts, prior reviews, and manufacturers.

STUDY SELECTION

Randomized controlled trials of CES versus usual care or sham CES that reported pain, depression, anxiety, or sleep outcomes in any language.

DATA EXTRACTION

Single-reviewer extraction checked by another; dual independent quality assessment; strength-of-evidence grading by the first author with subsequent group discussion.

DATA SYNTHESIS

Twenty-eight articles from 26 randomized trials met eligibility criteria. The 2 trials that compared CES with usual care were small, and neither reported a statistically significant benefit in pain or anxiety outcomes for patients with fibromyalgia or anxiety, respectively. Fourteen trials with sham or placebo controls involving patients with painful conditions, such as headache, neuromuscular pain, or musculoskeletal pain, had conflicting results. Four trials done more than 40 years ago and 1 from 2014 provided low-strength evidence of a possible modest benefit compared with sham treatments in patients with anxiety and depression. Trials in patients with insomnia (n = 2), insomnia and anxiety (n = 1), or depression (n = 3) had inconclusive or conflicting results. Low-strength evidence suggested that CES does not cause serious side effects.

LIMITATION

Most trials had small sample sizes and short durations; all had high risk of bias due to inadequate blinding.

CONCLUSION

Evidence is insufficient that CES has clinically important effects on fibromyalgia, headache, neuromusculoskeletal pain, degenerative joint pain, depression, or insomnia; low-strength evidence suggests modest benefit in patients with anxiety and depression.

PRIMARY FUNDING SOURCE

Veterans Affairs Quality Enhancement Research Initiative. (PROSPERO: CRD42016023951).

Consensus Recommendations for the Clinical Application of Repetitive Transcranial Magnetic Stimulation (rTMS) in the Treatment of Depression

OBJECTIVE

To provide expert recommendations for the safe and effective application of repetitive transcranial magnetic stimulation (rTMS) in the treatment of major depressive disorder (MDD).

PARTICIPANTS

Participants included a group of 17 expert clinicians and researchers with expertise in the clinical application of rTMS, representing both the National Network of Depression Centers (NNDC) rTMS Task Group and the American Psychiatric Association Council on Research (APA CoR) Task Force on Novel Biomarkers and Treatments.

EVIDENCE

The consensus statement is based on a review of extensive literature from 2 databases (OvidSP MEDLINE and PsycINFO) searched from 1990 through 2016. The search terms included variants of major depressive disorder and transcranial magnetic stimulation. The results were limited to articles written in English that focused on adult populations. Of the approximately 1,500 retrieved studies, a total of 118 publications were included in the consensus statement and were supplemented with expert opinion to achieve consensus recommendations on key issues surrounding the administration of rTMS for MDD in clinical practice settings.

CONSENSUS PROCESS

In cases in which the research evidence was equivocal or unclear, a consensus decision on how rTMS should be administered was reached by the authors of this article and is denoted in the article as "expert opinion."

CONCLUSIONS

Multiple randomized controlled trials and published literature have supported the safety and efficacy of rTMS antidepressant therapy. These consensus recommendations, developed by the NNDC rTMS Task Group and APA CoR Task Force on Novel Biomarkers and Treatments, provide comprehensive information for the safe and effective clinical application of rTMS in the treatment of MDD.

Neurophysiologic Correlates of Headache Pain in Subjects With Major Depressive Disorder

BACKGROUND

Headache pain is often comorbid with major depressive disorder (MDD) and is associated with greater symptom burden, disability, and suicidality. The biological correlates of headache pain in MDD, however, remain obscure. The purpose of this study was to examine the association between brain oscillatory activity and headache pain in MDD subjects.

METHODS

A total of 64 subjects with MDD who were free of psychoactive medications were evaluated for severity of headache pain in the past week. Brain function was assessed using resting-state quantitative electroencephalography (qEEG). We derived cordance in the theta (4-8 Hz) and alpha (8-12 Hz) frequency bands at each electrode, and examined correlations with headache pain in regions of interest while controlling for depression severity. Frontal and posterior asymmetry in alpha power was calculated in regions of interest.

RESULTS

Headache pain severity was associated with depression severity ( r = 0.447, P < .001). In bilateral frontal and right posterior regions, alpha cordance was significantly associated with headache intensity, including when controlling for depression severity. The direction of the correlation was positive anteriorly and negative posteriorly. Frontal left dominant alpha asymmetry correlated with severity of headache but not depression symptoms.

CONCLUSION

Alterations in brain oscillations identified by alpha cordance and alpha asymmetry may be associated with the pathophysiology of headache pain in depression. These findings should be prospectively confirmed.

Can neurophysiologic measures serve as biomarkers for the efficacy of repetitive transcranial magnetic stimulation treatment of major depressive disorder?

Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for Major Depressive Disorder (MDD). There are clinical data that support the efficacy of many different approaches to rTMS treatment, and it remains unclear what combination of stimulation parameters is optimal to relieve depressive symptoms. Because of the costs and complexity of studies that would be necessary to explore and compare the large number of combinations of rTMS treatment parameters, it would be useful to establish reliable surrogate biomarkers of treatment efficacy that could be used to compare different approaches to treatment. This study reviews the evidence that neurophysiologic measures of cortical excitability could be used as biomarkers for screening different rTMS treatment paradigms. It examines evidence that: (1) changes in excitability are related to the mechanism of action of rTMS; (2) rTMS has consistent effects on measures of excitability that could constitute reliable biomarkers; and (3) changes in excitability are related to the outcomes of rTMS treatment of MDD. An increasing body of evidence indicates that these neurophysiologic measures have the potential to serve as reliable biomarkers for screening different approaches to rTMS treatment of MDD.

Quantitative Electroencephalographic Biomarkers in Preclinical and Human Studies of Huntington's Disease: Are They Fit-for-Purpose for Treatment Development?

A major focus in development of novel therapies for Huntington's disease (HD) is identification of treatments that reduce the burden of mutant huntingtin (mHTT) protein in the brain. In order to identify and test the efficacy of such therapies, it is essential to have biomarkers that are sensitive to the effects of mHTT on brain function to determine whether the intervention has been effective at preventing toxicity in target brain systems before onset of clinical symptoms. Ideally, such biomarkers should have a plausible physiologic basis for detecting the effects of mHTT, be measureable both in preclinical models and human studies, be practical to measure serially in clinical trials, and be reliably measurable in HD gene expansion carriers (HDGECs), among other features. Quantitative electroencephalography (qEEG) fulfills many of these basic criteria of a "fit-for-purpose" biomarker. qEEG measures brain oscillatory activity that is regulated by the brain structures that are affected by mHTT in premanifest and early symptom individuals. The technology is practical to implement in the laboratory and is well tolerated by humans in clinical trials. The biomarkers are measureable across animal models and humans, with findings that appear to be detectable in HDGECs and translate across species. We review here the literature on recent developments in both preclinical and human studies of the use of qEEG biomarkers in HD, and the evidence for their usefulness as biomarkers to help guide development of novel mHTT lowering treatments.

Trigeminal Nerve Stimulation for Comorbid Posttraumatic Stress Disorder and Major Depressive Disorder

OBJECTIVES

External stimulation of the trigeminal nerve (eTNS) is an emerging neuromodulation therapy for epilepsy and depression. Preliminary studies suggest it has an excellent safety profile and is associated with significant improvements in seizures and mood. Neuroanatomical projections of the trigeminal system suggest eTNS may alter activity in structures regulating mood, anxiety, and sleep. In this proof-of-concept trial, the effects of eTNS were evaluated in adults with posttraumatic stress disorder (PTSD) and comorbid unipolar major depressive disorder (MDD) as an adjunct to pharmacotherapy for these commonly co-occurring conditions.

MATERIALS AND METHODS

Twelve adults with PTSD and MDD were studied in an eight-week open outpatient trial (age 52.8 [13.7 sd], 8F:4M). Stimulation was applied to the supraorbital and supratrochlear nerves for eight hours each night as an adjunct to pharmacotherapy. Changes in symptoms were monitored using the PTSD Patient Checklist (PCL), Hamilton Depression Rating Scale (HDRS-17), Quick Inventory of Depressive Symptomatology (QIDS-C), and the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q).

RESULTS

Over the eight weeks, eTNS treatment was associated with significant decreases in PCL (p = 0.003; median decrease of 15 points; effect size d 1.5), HDRS-17 (p < 0.001; 42% response rate, 25% remission; d 2.1), and QIDS-C scores (p < 0.001; d 1.8), as well as an improvement in quality of life (Q-LES-Q, p < 0.01). eTNS was well tolerated with few treatment emergent adverse events.

CONCLUSIONS

Significant improvements in PTSD and depression severity were achieved in the eight weeks of acute eTNS treatment. This novel approach to wearable brain stimulation may have use as an adjunct to pharmacotherapy in these disorders if efficacy and tolerability are confirmed with additional studies.

Intermediate phenotypes and biomarkers of treatment outcome in major depressive disorder

Major depressive disorder (MDD) is a pleomorphic illness originating from gene x environment interactions. Patients with differing symptom phenotypes receive the same diagnosis and similar treatment recommendations without regard to genomics, brain structure or function, or other physiologic or psychosocial factors. Using this present approach, only one third of patients enter remission with the first medication prescribed, and patients may take longer than 1 year to enter remission with repeated trials. Research to improve treatment effectiveness recently has focused on identification of intermediate phenotypes (IPs) that could parse the heterogeneous population of patients with MDD into subgroups with more homogeneous responses to treatment. Such IPs could be used to develop biomarkers that could be applied clinically to match patients with the treatment that would be most likely to lead to remission. Putative biomarkers include genetic polymorphisms, RNA and protein expression (transcriptome and proteome), neurotransmitter levels (metabolome), additional measures of signaling cascades, oscillatory synchrony, neuronal circuits and neural pathways (connectome), along with other possible physiologic measures. All of these measures represent components of a continuum that extends from proximity to the genome to proximity to the clinical phenotype of depression, and there are many levels along this continuum at which useful IPs may be defined. Because of the highly integrative nature of brain systems and the complex neurobiology of depression, the most useful biomarkers are likely to be those with intermediate proximity both to the genome and the clinical phenotype of MDD. Translation of findings across the spectrum from genotype to phenotype promises to better characterize the complex disruptions in signaling and neuroplasticity that accompany MDD, and ultimately to lead to greater understanding of the causes of depressive illness.

The Antidepressant Treatment Response Index as a Predictor of Reboxetine Treatment Outcome in Major Depressive Disorder

Biomarkers to predict clinical outcomes early during the treatment of major depressive disorder (MDD) could reduce suffering and improve outcomes. A quantitative electroencephalogram (qEEG) biomarker, the Antidepressant Treatment Response (ATR) index, has been associated with outcomes of treatment with selective serotonin reuptake inhibitor antidepressants in patients with MDD. Here, we report the results of a post hoc analysis initiated to evaluate whether the ATR index may also be associated with reboxetine treatment outcome, given that its putative mechanism of action is via norepinephrine reuptake inhibition (NRI). Twenty-five adults with MDD underwent qEEG studies during open-label treatment with reboxetine at doses of 8 to 10 mg daily for 8 weeks. The ATR index calculated after 1 week of reboxetine treatment was significantly associated with overall Hamilton Depression Rating Scale (HAM-D) improvement at week 8 (r=0.605, P=.001), even after controlling for baseline depression severity (P=.002). The ATR index predicted response (≥50% reduction in HAM-D) with 70.6% sensitivity and 87.5% specificity, and remission (final HAM-D≤7) with 87.5% sensitivity and 64.7% specificity. These results suggest that the ATR index may be a useful biomarker of clinical response during NRI treatment of adults with MDD. Future studies are warranted to investigate further the potential utility of the ATR index as a predictor of noradrenergic antidepressant treatment response.

Antidepressant treatment history and drug-placebo separation in a placebo-controlled trial in major depressive disorder

RATIONALE

A history of antidepressant treatment may predispose subjects toward placebo nonresponse in randomized controlled trials (RCTs) in major depressive disorder (MDD).

OBJECTIVE

The objective of this study is to examine self-reported prior antidepressant treatment and response in relationship to clinical outcome in an 8-week randomized trial of reuptake inhibitor antidepressant medication (MED) versus placebo (PBO) administered along with limited supportive care.

METHODS

Chi-square and MMRM analyses examined MED vs. PBO outcomes in antidepressant-naïve vs. antidepressant-experienced subjects. Linear regression models examined treatment history along with covariates as predictors of clinical improvement.

RESULTS

Among completers (n = 56), there was no significant difference in response rate between MED (53.3 %) and PBO (42.3 %) (χ (2) = 0.33, p = 0.28, 1-tailed). The antidepressant-experienced subgroup (n = 37), however, showed a significantly greater response rate to MED (52.4 %) than PBO (25.0 %) (χ (2) = 2.82, p = 0.047, 1-tailed). The full intent-to-treat (ITT) sample (n = 69) did not show a significant difference between MED and PBO group improvement over time, but in the treatment-experienced subgroup (n = 46), MED showed significantly greater improvement than PBO (coefficient = .39, SE = .23, p = .045, 1-tailed). A history of prior antidepressant treatment predicted poorer overall response independent of pretreatment symptom severity, number or length of previous episodes, subject expectations, or family history of MDD.

CONCLUSIONS

Treatment history appears to constitute a factor that is distinct from other commonly studied illness characteristics or expectancy measures, and that impacts overall response as well as drug-placebo separation in RCTs.

Rhythms and blues: modulation of oscillatory synchrony and the mechanism of action of antidepressant treatments

Treatments for major depressive disorder (MDD) act at different hierarchical levels of biological complexity, ranging from the individual synapse to the brain as a whole. Theories of antidepressant medication action traditionally have focused on the level of cell-to-cell interaction and synaptic neurotransmission. However, recent evidence suggests that modulation of synchronized electrical activity in neuronal networks is a common effect of antidepressant treatments, including not only medications, but also neuromodulatory treatments such as repetitive transcranial magnetic stimulation. Synchronization of oscillatory network activity in particular frequency bands has been proposed to underlie neurodevelopmental and learning processes, and also may be important in the mechanism of action of antidepressant treatments. Here, we review current research on the relationship between neuroplasticity and oscillatory synchrony, which suggests that oscillatory synchrony may help mediate neuroplastic changes related to neurodevelopment, learning, and memory, as well as medication and neuromodulatory treatment for MDD. We hypothesize that medication and neuromodulation treatments may have related effects on the rate and pattern of neuronal firing, and that these effects underlie antidepressant efficacy. Elucidating the mechanisms through which oscillatory synchrony may be related to neuroplasticity could lead to enhanced treatment strategies for MDD.

A multisite, naturalistic, observational study of transcranial magnetic stimulation for patients with pharmacoresistant major depressive disorder: durability of benefit over a 1-year follow-up period

OBJECTIVE

Transcranial magnetic stimulation (TMS) is an effective and safe acute treatment for patients not benefiting from antidepressant pharmacotherapy. Few studies have examined its longer term durability. This study assessed the long-term effectiveness of TMS in naturalistic clinical practice settings following acute treatment.

METHOD

Adult patients with a primary diagnosis of unipolar, nonpsychotic major depressive disorder (DSM-IV clinical criteria), who did not benefit from antidepressant medication, received TMS treatment in 42 clinical practices. Two hundred fifty-seven patients completed a course of acute TMS treatment and consented to follow-up over 52 weeks. Assessments were obtained at 3, 6, 9, and 12 months. The study was conducted between March 2010 and August 2012.

RESULTS

Compared with pre-TMS baseline, there was a statistically significant reduction in mean total scores on the Clinical Global Impressions-Severity of Illness scale (primary outcome), 9-Item Patient Health Questionnaire, and Inventory of Depressive Symptoms-Self Report (IDS-SR) at the end of acute treatment (all P < .0001), which was sustained throughout follow-up (all P < .0001). The proportion of patients who achieved remission at the conclusion of acute treatment remained similar at conclusion of the long-term follow-up. Among 120 patients who met IDS-SR response or remission criteria at the end of acute treatment, 75 (62.5%) continued to meet response criteria throughout long-term follow-up. After the first month, when the majority of acute TMS tapering was completed, 93 patients (36.2%) received reintroduction of TMS. In this group, the mean (SD) number of TMS treatment days was 16.2 (21.1).

CONCLUSIONS

TMS demonstrates a statistically and clinically meaningful durability of acute benefit over 12 months of follow-up. This was observed under a pragmatic regimen of continuation antidepressant medication and access to TMS retreatment for symptom recurrence.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01114477.

Role of pill-taking, expectation and therapeutic alliance in the placebo response in clinical trials for major depression

BACKGROUND

Pill-taking, expectations and therapeutic alliance may account for much of the benefit of medication and placebo treatment for major depressive disorder (MDD). Aims To examine the effects of medication, placebo and supportive care on treatment outcome, and the relationships of expectations and therapeutic alliance to improvement.

METHOD

A total of 88 participants were randomised to 8 weeks of treatment with supportive care alone or combined with double-blind treatment with placebo or antidepressant medication. Expectations of medication effectiveness, general treatment effectiveness and therapeutic alliance were measured (trial registration at ClinicalTrials.gov: NCT00200902).

RESULTS

Medication or placebo plus supportive care were not significantly different but had significantly better outcome than supportive care alone. Therapeutic alliance predicted response to medication and placebo; expectations of medication effectiveness at enrolment predicted only placebo response.

CONCLUSIONS

Pill treatment yielded better outcome than supportive care alone. Medication expectations uniquely predicted placebo treatment outcome and were formed by time of enrolment, suggesting that they were shaped by prior experiences outside the clinical trial.

Neurophysiologic predictors of response to atomoxetine in young adults with attention deficit hyperactivity disorder: a pilot project

Atomoxetine is a non-stimulant medication with sustained benefit throughout the day, and is a useful pharmacologic treatment option for young adults with Attention-Deficit/Hyperactivity Disorder (ADHD). It is difficult to determine, however, those patients for whom atomoxetine will be both effective and advantageous. Patients may need to take the medication for several weeks before therapeutic benefit is apparent, so a biomarker that could predict atomoxetine effectiveness early in the course of treatment could be clinically useful. There has been increased interest in the study of thalamocortical oscillatory activity using quantitative electroencephalography (qEEG) as a biomarker in ADHD. In this study, we investigated qEEG absolute power, relative power, and cordance, which have been shown to predict response to reuptake inhibitor antidepressants in Major Depressive Disorder (MDD), as potential predictors of response to atomoxetine. Forty-four young adults with ADHD (ages 18-30) enrolled in a multi-site, double-blind placebo-controlled study of the effectiveness of atomoxetine and underwent serial qEEG recordings at pretreatment baseline and one week after the start of medication. qEEG measures were calculated from a subset of the sample (N = 29) that provided useable qEEG recordings. Left temporoparietal cordance in the theta frequency band after one week of treatment was associated with ADHD symptom improvement and quality of life measured at 12 weeks in atomoxetine-treated subjects, but not in those treated with placebo. Neither absolute nor relative power measures selectively predicted improvement in medication-treated subjects. Measuring theta cordance after one week of treatment could be useful in predicting atomoxetine treatment response in adult ADHD.

Do prefrontal midline electrodes provide unique neurophysiologic information in Major Depressive Disorder?

Brain oscillatory activity from the midline prefrontal region has been shown to reflect brain dysfunction in subjects with Major Depressive Disorder (MDD). It is not known, however, whether electrodes from this area provide unique information about brain function in MDD. We examined a set of midline sites and two other prefrontal locations for detecting cerebral activity differences between subjects with MDD and healthy controls. Resting awake quantitative EEG (qEEG) data were recorded from 168 subjects: 47 never-depressed adults and 121 with a current major depressive episode. Individual midline electrodes (Fpz, Fz, Cz, Pz, and Oz) and prefrontal electrodes outside the hairline (Fp1, Fp2) were examined with absolute and relative power and cordance in the theta band. We found that MDD subjects exhibited higher values of cordance (p = 0.0066) at Fpz than controls; no significant differences were found at other locations, and power measures showed trend-level differences. Depressed adults showed higher midline cordance than did never-depressed subjects at the most-anterior midline channel. Salient abnormalities in MDD may be detectable by focusing on the prefrontal midline region, and EEG metrics from focused electrode arrays may offer clinical practicality for clinical monitoring.

Rostral anterior cingulate activity in major depressive disorder: state or trait marker of responsiveness to medication?

High rostral anterior cingulate cortex (rACC) activity has been shown to predict antidepressant treatment response; however, it is unclear whether this is a fixed versus variable marker of responsiveness. The authors measured rACC theta current density in 22 subjects 5 weeks before and again immediately before 5 weeks of blinded treatment with sertraline. Mixed-effects regression analysis found that the relationship between response and rACC activity depended significantly on the timing of the rACC assessment; rACC activity measured immediately before treatment was a significantly better predictor of response. rACC activity may constitute a variable "state" indicator of responsiveness to antidepressants.