Measuring change in anhedonia using the "Happy Faces" task pre- to post-repetitive transcranial magnetic stimulation (rTMS) treatment to left dorsolateral prefrontal cortex in Major Depressive Disorder (MDD): relation to empathic happiness

Anhedonia as a Core Symptom of Depression and a Construct for Biological Research

Anhedonia is a key psychiatric symptom that has seen significant advances in its understanding in both clinical practice and research over the past few decades. Once considered primarily a feature of depression, recent studies have shown that anhedonia is also a core element of other psychiatric disorders and contributes to considerable morbidity, mortality, and suicidality. Emerging models of psychopathology and illness emphasize the transdiagnostic relevance of anhedonia. At the same time, neuroimaging research has provided deeper insights into its underlying pathophysiology, and several assessment scales with strong psychometric properties have been developed. Various treatment strategies-including psychopharmacology, neuromodulation, and psychotherapy-have demonstrated varying degrees of effectiveness. This review discusses the evolving understanding of anhedonia, its significance as both a symptom and a diagnostic marker, its prevalence, and its pathophysiological underpinnings. Additionally, the authors provide an overview of key assessment tools and explore the range of treatment approaches studied to date.

Anhedonia: Current and future treatments

Anhedonia is a transdiagnostic domain that leads to poor disorder outcome and low remission rates. This narrative review describes a broad range of interventions targeting anhedonia, including pharmacological, neuromodulatory, behavioral, and lifestyle-based approaches. Drugs such as vortioxetine, agomelatine, bupropion, ketamine, and brexpiprazole show promising anti-anhedonic effects, while traditional antidepressants, such as serotonin-norepinephrine reuptake inhibitors (SNRIs) and, even more so, selective serotonin reuptake inhibitors (SSRIs), are less effective. Neuromodulation techniques, including repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and transcutaneous auricular vagus nerve stimulation, proved effective at improving anhedonia, particularly when used in targeted areas. Psychotherapeutic interventions, including behavioral activation, mindfulness-based strategies, and savoring techniques, also help re-engage patients with pleasurable activities and enhance positive affect. Innovative treatments, such as aticaprant and psilocybin, showed promising results. Substantial evidence suggests that improving anhedonia leads to better psychosocial functioning, quality of life, and sustained remission. Although most data come from short-term studies, several long-term analyses suggest that maintaining hedonic improvements is feasible and beneficial. The reviewed evidence underscores the importance of routine assessment of anhedonia and the integration of symptom-specific strategies. Tailoring interventions to address individual patterns of reward disruption may optimize outcomes for patients with anhedonia.

The effect of repetitive transcranial magnetic stimulation on the Hamilton Depression Rating Scale-17 criterion in patients with major depressive disorder without psychotic features: a systematic review and meta-analysis of intervention studies

AIM

In line with the publication of clinical information related to the therapeutic process of repetitive transcranial magnetic stimulation (rTMS) and the updating of relevant treatment guidelines, the present meta-analysis study was designed and conducted to determine the effect of repetitive transcranial magnetic stimulation (rTMS) on the Hamilton Depression Rating Scale-17 (HDRS-17) criterion in patients with major depressive disorder (MDD) without psychotic features.

METHODS

In this study, a systematic search was conducted in electronic databases such as PubMed [Medline], Scopus, Web of Science, Embase, Ovid, Cochrane Library, and ClinicalTrials. gov using relevant keywords. The search period in this study was from January 2000 to January 2022, which was updated until May 2023. Randomized controlled trials (RCTs) that determined the effect of repetitive transcranial magnetic stimulation (rTMS) on the Hamilton Depression Rating Scale-17 (HDRS-17) criterion in patients with major depressive disorder (MDD) without psychotic features were included in the analysis. The quality of the included RCTs was assessed using the Cochrane Risk of Bias checklist. Statistical analyses were performed using STATA (Version 16) and RevMan (Version 5).

RESULTS

Following the combination of results from 16 clinical trial studies in the present meta-analysis, it was found that the mean Hamilton Depression Rating Scale-17 (HDRS-17) in patients with major depressive disorder (MDD) decreases by an average of 1.46 units (SMD: -1.46; % 95 CI: -1.65, -1.27, I square: 45.74%; P heterogeneity: 0.56). Subgroup analysis results indicated that the standardized mean difference of Hamilton Depression Rating Scale-17 (HDRS-17) varied based on the number of treatment sessions: patients receiving 10 or fewer repetitive transcranial magnetic stimulation (rTMS) sessions showed a mean Hamilton Depression Rating Scale-17 (HDRS-17) reduction of 2.60 units (SMD: -2.60; % 95 CI: -2.86, -2.33, I square: 55.12%; P heterogeneity: 0.55), while those receiving 11 to 20 sessions showed a mean Hamilton Depression Rating Scale-17 (HDRS-17) reduction of 0.28 units (SMD: -0.28; % 95 CI: -0.65, -0.09, I square: 39.91%; P heterogeneity: 0.89).

CONCLUSION

In conclusion, our meta-analysis demonstrates the efficacy of repetitive transcranial magnetic stimulation (rTMS) in reducing depressive symptoms in major depressive disorder (MDD) patients. The complex results of subgroup analysis revealed insight on the possible benefits of a more focused strategy with fewer sessions, as well as the impact of treatment session frequency. These findings add to our understanding of repetitive transcranial magnetic stimulation (rTMS) as a therapeutic intervention for the treatment of major depressive illnesses.

Unique versus shared neural correlates of externalizing psychopathology in late childhood

Childhood externalizing psychopathology is heterogeneous. Symptom variability in conduct disorder (CD), oppositional defiant disorder (ODD), attention-deficit/hyperactivity disorder (ADHD), and callous-unemotional (CU) traits designate different subgroups of children with externalizing problems who have specific treatment needs. However, CD, ODD, ADHD, and CU traits are highly comorbid. Studies need to generate insights into shared versus unique risk mechanisms, including through the use of functional magnetic resonance imaging (fMRI). In this study, we tested whether symptoms of CD, ODD, ADHD, and CU traits were best represented within a bifactor framework, simultaneously modeling shared (i.e., general externalizing problems) and unique (i.e., symptom-specific) variance, or through a four-correlated factor or second-order factor model. Participants (N = 11,878, age, M = 9 years) were from the Adolescent Brain and Cognitive Development Study. We used questionnaire and functional magnetic resonance imaging data (emotional N-back task) from the baseline assessment. A bifactor model specifying a general externalizing and specific CD, ODD, ADHD, and CU traits factors demonstrated the best fit. The four-correlated and second-order factor models both fit the data well and were retained for analyses. Across models, reduced right amygdala activity to fearful faces was associated with more general externalizing problems and reduced dorsolateral prefrontal cortex activity to fearful faces was associated with higher CU traits. ADHD scores were related to greater right nucleus accumbens activation to fearful and happy faces. Results give insights into risk mechanisms underlying comorbidity and heterogeneity within externalizing psychopathology. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The effect of noninvasive brain stimulation on anhedonia in patients with schizophrenia and depression: A systematic review and meta-analysis

Anhedonia is a transdiagnostic symptom found in patients with schizophrenia and depression. Current pharmacological interventions for anhedonia are unsatisfactory in a considerable proportion of patients. There has been growing interest in applying noninvasive brain stimulation (NIBS) to patients with anhedonia. However, evidence for the efficacy of NIBS for anhedonia remain inconsistent. This study systematically identified all studies that measured anhedonia and applied NIBS in patients with schizophrenia or depression. We conducted a search using the various databases in English (PubMed, EBSCOHost (PsycInfo/PsycArticles), Web of Science) and Chinese (China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform) languages, and reviewed original research articles on NIBS published from January 1989 to July 2023. Our search had identified 15 articles for quantitative synthesis, with three concerning schizophrenia samples, 11 concerning samples with depression, and one concerning both clinical samples. We conducted a meta-analysis based on the 15 included studies, and the results suggested that NIBS could improve anhedonia symptoms in schizophrenia patients and patients with depression, with a medium-to-large effect size. Our findings are preliminary, given the limited number of included studies. Future NIBS research should measure anhedonia as a primary outcome and should recruit transdiagnostic samples.

Clinical effects of anodal tDCS and identifying response markers in post-traumatic stress disorder (PTSD): An open-label study

Transcranial direct current stimulation (tDCS) is a promising treatment for post-traumatic stress disorder (PTSD). However, not all patients respond to this type of treatment. The first aim of present study was to examine efficacy of tDCS for PTSD, depression, anxiety, and anhedonia in patients with PTSD. The second aim of this study was to examine the demographic, clinical, and psychological factors that may predict response to tDCS. In this open-label study, 103 PTSD patients underwent 10 sessions of tDCS (2 mA, 20 min). The anodal and cathodal electrodes were placed over the left dorsolateral prefrontal cortex (DLPFC; F3) and right supra-orbital (FP2) Respectively. Clinical outcome measures included Posttraumatic the Stress Disorder Checklist for DSM-5 (PCL-5), the Beck Depression Inventory (BDI-II), the Beck Anxiety Inventory (BAI), and the Snaith-Hamilton Pleasure Scale (SHAPS). There was an overall significant improvement in symptoms of PTSD, depression, anxiety, and anhedonia from pre- to post-treatment. Results also revealed that non-responders had higher severity at baseline for depression, anxiety, and anhedonia. However, higher severity of depression and anhedonia at baseline predicted response status, with higher severity associated with greater likelihood of non-response. tDCS of the left dLPFC and right supra-orbital appears to have a positive effect in reducing PTSD and related symptoms. These initial results could have an important influence on the adoption of anodal tDCS over the left DLPFC for PTSD, by enabling the early identification of patients who respond to tDCS.

tDCS efficacy and utility of anhedonia and rumination as clinical predictors of response to tDCS in major depressive disorder (MDD)

BACKGROUND

Anhedonia and rumination are mental disorders' transdiagnostic features but remain difficult to treat. Transcranial direct current stimulation (tDCS) is a proven treatment for depression, but its effects on anhedonia and rumination and whether anhedonia and rumination can be used as a predictive biomarker of treatment response is not well known. This study aimed to investigate the tDCS efficacy and identify the predictive role of anhedonia and rumination in response to tDCS in patients with MDD.

METHODS

182 patients received 10 tDCS sessions delivered at 2 mA to left (anode) dorsolateral prefrontal cortex (DLPFC). Hamilton Rating Scale for Depression (HRSD-17), Snaith-Hamilton Pleasure Scale (SHAPS), and the 10-item Ruminative Response Scale (RRS-10) was administered to patients with MDD before treatment, following it, and after two weeks of tDCS.

RESULTS

There was an overall significant improvement in anhedonia from pre- to post-treatment. Regression analyses revealed that responders had higher baseline anhedonia and rumination (reflective pondering) scores. We found that the reduction in HRSD scores after tDCS was significantly associated with anhedonia's baseline values while no relation was found between baseline rumination and tDCS treatment response.

CONCLUSION

These results provide new evidence that pronounced anhedonia may be a significant clinical predictor of response to tDCS. Patients with severe or low baseline rumination had an equal chance of achieving clinical response. Prospective tDCS studies are necessary to validate the predictive value of the derived model.

Interventions for deficits in recognition of emotions in facial expressions in major depressive disorder: An updated systematic review of clinical trials

The recognition of emotions in facial expressions (REFE) is a core construct of social cognition. In the last decades, studies have showed that REFE is altered in major depressive disorder (MDD), but the evidence is conflicting. Thus, we conducted a systematic review of clinical trials involving therapeutic interventions in MDD and any evaluation of REFE to update (2018-2023) and systematically evaluate the evidence derived from controlled clinical trials on the effects of therapeutic strategies to MDD on the REFE. Eleven studies were included in the final review. Some interventions, including drugs (ketamine, bupropion, psylocibin) and non-pharmacological strategies (psychotherapy) seem to be able to reduce pre-existing REFE biases in MDD patients. However, there was a high heterogeneity in the evaluated studies, in terms of sample, interventions, tasks and results. Further studies and more consistent evaluation tools are highly needed to better understand nuanced deficits and specific actions of different treatment options.

Anhedonia and Depressive Disorders

Anhedonia is a core symptom of depression and of several psychiatric disorders. Anhedonia has however expanded from its original definition to encompass a spectrum of reward processing deficits that received much interest in the last decades. It is a relevant risk factor for possible suicidal behaviors, and that it may operate as an independent risk factor for suicidality apart from the episode severity. Anhedonia has also been linked to inflammation with a possible reciprocal deleterious effect on depression. Its neurophysiological bases mainly include alterations in striatal and prefrontal areas, with dopamine being the most involved neurotransmitter. Anhedonia is thought to have a significant genetic component and polygenic risk scores are a possible tool for predicting an individual's risk for developing anhedonia. Traditional antidepressants, such as selective serotonin reuptake inhibitors, showed a limited benefit on anhedonia, also considering their potential pro-anhedonic effect in some subjects. Other treatments may be more effective in treating anhedonia, such as agomelatine, vortioxetine, ketamine and transcranial magnetic stimulation. Psychotherapy is also widely supported, with cognitive-behavioral therapy and behavioral activation both showing benefit. In conclusion, a large body of evidence suggests that anhedonia is, at least partially, independent from depression, therefore it needs careful assessment and targeted treatment.

The Neural Correlates of the Recognition of Emotional Intensity Deficits in Major Depression: An ERP Study

PURPOSE

Deficits in facial emotional intensity recognition have been associated with social cognition in patients with major depression. The study examined multiple event-related potential (ERP) components in patients with major depression and investigated the relationships between ERPs, social cognition, and clinical features.

PARTICIPANTS AND METHODS

Thirty-one patients met DSM-IV diagnosis of depression and 31 healthy participants completed the emotion intensity recognition task (EIRT), while ERPs were recorded. Data on ERP components (P100, N170, P200, and P300) were analyzed.

RESULTS

The behavioral results showed that patients with major depression performed worse on EIRT, including all six categories of emotions (sadness, disgust, happiness, surprise, anger, and fear), compared to healthy participants. The ERP results showed that patients with major depression exhibited higher P100 amplitudes for sad and happy faces than healthy participants; P300 amplitudes induced by sad and surprise faces were also higher than in healthy participants, mainly in the central and temporal lobes. A positive correlation was found between sadness intensity scores and P100 amplitudes in patients with major depression.

CONCLUSION

Patients with major depression are biased in their identification of facial expressions indicating emotional intensity. Specifically, they have emotional biases in the early and late stages of cognitive processing, mainly in the form of sensitivity to sad stimuli. It may lead to a persistent rumination of sadness that is detrimental to the remission of depression. Additionally, patients with major depression devote different amounts of cognitive resources for different intensities of sad faces during the preconscious stage of cognitive processing. The more intense their perception of sadness, the more cognitive resources they devote. Therefore, the assessment of the intensity of facial expressions is an important research topic, with clinical implications on social cognitive function in patients with major depression.

Bilateral theta-burst stimulation on emotional processing in major depressive disorder: A functional neuroimaging study from a randomized, double-blind, sham-controlled trial

AIM

Bilateral theta-burst stimulation (biTBS; intermittent TBS over the left dorsolateral prefrontal cortex [DLPFC] and continuous TBS over the right DLPFC) has demonstrated efficacy in improving symptoms in patients with major depressive disorder (MDD). However, the underlying brain mechanisms remain unknown. The authors aimed to investigate the antidepressant efficacy of biTBS monotherapy and its effects on the brain responses measured by functional magnetic resonance imaging (fMRI) during emotional processing in MDD.

METHODS

The authors conducted a double-blind, randomized, sham-controlled trial of patients with MDD who exhibited no responses to at least one adequate antidepressant treatment for the prevailing episode. Recruited patients were randomly assigned to 10 biTBS monotherapy or sham stimulation sessions. The fMRI scans during performing emotional recognition task were obtained at baseline and after 10 sessions of treatment. Depressive symptoms were assessed using the 21-item Hamilton Rating Scale for Depression at baseline and the weeks 4, 8, 12, 16, 20, and 24 week.

RESULTS

The biTBS group (n = 17) exhibited significant decreases in depression scores compared with the sham group (n = 11) at week 8 (70% vs 40%; P = 0.02), and the significant differences persisted during the 24-week follow-up periods. At week 4, when the treatment course was completed, patients in the biTBS group, but not in the sham group, exhibited increased brain activities over the left superior and middle frontal gyrus during negative emotional stimuli.

CONCLUSION

The authors' findings provide the first evidence regarding the underlying neural mechanisms of biTBS therapy to improve clinical symptoms in patients with MDD.

Change of Circulating Vascular Endothelial Growth Factor Level and Reduction of Anhedonia Are Associated in Patients With Major Depressive Disorder Treated With Repetitive Transcranial Magnetic Stimulation

AIM

Vascular endothelial growth factor (VEGF) has been implicated in mediating the effect of antidepressant therapies as it plays a significant role in the neurogenesis. Anhedonia, an endophenotype of major depressive disorder (MDD), is related to the dorsolateral prefrontal cortex, the major focus of brain stimulation in MDD. The aim of our study was to analyze the change of serum VEGF level after rTMS treatment in association with anhedonia.

MATERIALS AND METHODS

A dataset of 17 patients with TRD who were treated with antidepressants and bilateral rTMS for 2 × 5 days was analyzed. Depression was measured by the Montgomery-Asberg Depression Scale (MADRS) and anhedonia by the Snaith-Hamilton Pleasure Scale (SHAPS) for monitoring the symptom changes. The serum VEGF levels and symptoms were assessed on the first (V1), on the 14th (V2), and on the 28th day (V3). The level of VEGF was measured by ELISA assay.

RESULTS

There was no significant association between MADRS scores and serum VEGF levels at any timepoint. The decrease in the SHAPS score was significantly associated with the increase in VEGF level between V1 and V2 (p = 0.001). The VEGF levels were significantly higher in non-responders than in responders (p = 0.04). The baseline VEGF level has been proven as a significant predictor of treatment response (p = 0.045).

CONCLUSION

Our results suggest that serum VEGF can be sensitive to the changes of anhedonia during rTMS treatment. Considering that the most widely used depression scales are not applicable for the assessment of anhedonia, measurement of anhedonia in rTMS treatment studies of patients with TRD can be suggested as more appropriate data on distinct pathogenic pathways and specific biomarkers of the disorder.

Circuit-Targeted Neuromodulation for Anhedonia

Despite the prevalence of anhedonia across multiple psychiatric disorders, its relevance to treatment selection and prognostication can be unclear (Davey et al., Psychol Med 42(10):2071-81, 2012). Given the challenges in pharmacological and psychosocial treatment, there has been increasing attention devoted to neuroanatomically-targeted treatments. This chapter will present a brief introduction to circuit-targeted therapeutics in psychiatry (Sect. 1), an overview of brain mapping as it relates to anhedonia (Sect. 2), a review of existing studies on brain stimulation for anhedonia (Sect. 3), and a description of emerging approaches to circuit-based neuromodulation for anhedonia (Sect. 4).

Neural signatures of saliency-mapping in anhedonia: A narrative review

Anhedonia is the loss of pleasure or motivation to engage in previously enjoyable activities, and is a transdiagnostic symptom associated with significant clinical impairment. Anhedonia is implicated in several different psychiatric disorders, presenting a promising opportunity for transdiagnostic treatment. Thus, developing targeted treatments for anhedonia is of critical importance for population mental health. An important first step in doing so is establishing a thorough understanding of the neural correlates of anhedonia. The Triple Network Model of Psychopathology provides a frame for how brain activity may go awry in anhedonia, specifically in the context of Salience Network (SN) function (i.e., saliency-mapping). We present a narrative review examining saliency-mapping as it relates to anhedonia severity in depressed and transdiagnostic adult samples. Results revealed increased anhedonia to be associated with hyperactivity of the SN at rest and in the context of negative stimuli, as well as a global lack of SN engagement in the context of positive stimuli. Potential treatments for anhedonia are placed within this model, and future directions for research are discussed.

Effects of transcranial magnetic stimulation on anhedonia in treatment resistant major depressive disorder

BACKGROUND

Anhedonia is one of the defining features of depression but it remains difficult to target and treat. Transcranial magnetic stimulation (TMS) is a proven treatment for depression, but its effects on anhedonia and whether anhedonia can be used as a predictive biomarker of response is not well known.

METHODS

Snaith-Hamilton Pleasure Scale was administered to patients with depression before and after a standard course of TMS in a naturalistic outpatient setting.

RESULTS

144 patients were analyzed. There was an overall significant improvement in anhedonia from pre- to post-treatment (7.69 ± 3.88 vs. 2.96 ± 3.45; p < .001). Significant correlations between improvements in anhedonia and other depressive symptoms were present (r = 0.55, p < .001). Logistic regression revealed that baseline anhedonia severity was not a significant predictor of clinical outcome.

CONCLUSION

This is the first large, naturalistic study examining the effects of standard, non-research TMS on anhedonia. Among depressed patients, TMS resulted in significant improvements in anhedonia. Patients with severe baseline anhedonia had an equal chance of achieving clinical response/remission. Patients with anhedonia should not be excluded from treatment if they are safe for outpatient care and otherwise appropriate candidates for treatment.

Therapeutic efficacy of connectivity-directed transcranial magnetic stimulation on anticipatory anhedonia

BACKGROUND

There are currently no effective treatments specifically targeting anticipatory anhedonia, a major symptom of severe depression which is associated with poor outcomes. The present study investigated the efficacy of individualized repetitive transcranial magnetic stimulation (rTMS) targeting the left dorsolateral prefrontal cortex (lDLPFC)-nucleus accumbens (NAcc) network on anticipatory anhedonia in depression.

METHODS

This randomized, double-blind, sham-controlled clinical trial (NCT03991572) enrolled 56 depression patients with anhedonia symptoms. Each participant received 15 once-daily sessions of rTMS at 10 Hz and 100% motor threshold. Stimulation was localized to the site of strongest IDLPFC-NAcc connectivity by functional magnetic resonance imaging. The Hamilton depression rating scale (HAMD) was used to measure depression severity, the temporal experience pleasure scale (TEPS) to measure anticipatory and consummatory anhedonia to specifically measure anticipatory/motivational anhedonia. Event-related potentials during the monetary incentive delay (MID) task were recorded to evaluate the electrophysiological correlates of reward anticipation and response.

RESULTS

Patients in the Real group showed significant improvements in anticipatory anhedonia and general depression symptoms posttreatment compared to the Sham group. The Real group also demonstrated more positive going cue-N2 and cue-P3 amplitude during MID reward trials after treatment. The change in cue-P3 posttreatment was positive correlated with improved TEPS-anti score.

CONCLUSION

Individualized rTMS of the lDLPFC-NAcc network can effectively alleviate anticipatory anhedonia and improved the reward seeking as evidenced by enhanced MID behavioral performance and more positive going cue-N2 and cue-P3. The lDLPFC-NAcc network plays a critical role in anticipatory reward and motivation processing.

DLPFC volume is a neural correlate of resilience in healthy high-risk individuals with both childhood maltreatment and familial risk for depression

BACKGROUND

Two prominent risk factors for major depressive disorder (MDD) are childhood maltreatment (CM) and familial risk for MDD. Despite having these risk factors, there are individuals who maintain mental health, i.e. are resilient, whereas others develop MDD. It is unclear which brain morphological alterations are associated with this kind of resilience. Interaction analyses of risk and diagnosis status are needed that can account for complex adaptation processes, to identify neural correlates of resilience.

METHODS

We analyzed brain structural data (3T magnetic resonance imaging) by means of voxel-based morphometry (CAT12 toolbox), using a 2 × 2 design, comparing four groups (N = 804) that differed in diagnosis (healthy v. MDD) and risk profiles (low-risk, i.e. absence of CM and familial risk v. high-risk, i.e. presence of both CM and familial risk). Using regions of interest (ROIs) from the literature, we conducted an interaction analysis of risk and diagnosis status.

RESULTS

Volume in the left middle frontal gyrus (MFG), part of the dorsolateral prefrontal cortex (DLPFC), was significantly higher in healthy high-risk individuals. There were no significant results for the bilateral superior frontal gyri, frontal poles, pars orbitalis of the inferior frontal gyri, and the right MFG.

CONCLUSIONS

The healthy high-risk group had significantly higher volumes in the left DLPFC compared to all other groups. The DLPFC is implicated in cognitive and emotional processes, and higher volume in this area might aid high-risk individuals in adaptive coping in order to maintain mental health. This increased volume might therefore constitute a neural correlate of resilience to MDD in high risk.

Distinct Symptom-Specific Treatment Targets for Circuit-Based Neuromodulation

OBJECTIVE

Treatment of different depression symptoms may require different brain stimulation targets with different underlying brain circuits. The authors sought to identify such targets, which could improve the efficacy of therapeutic brain stimulation and facilitate personalized therapy.

METHODS

The authors retrospectively analyzed two independent cohorts of patients who received left prefrontal transcranial magnetic stimulation (TMS) for treatment of depression (discovery sample, N=30; active replication sample, N=81; sham replication sample, N=87). Each patient's TMS site was mapped to underlying brain circuits using functional connectivity MRI from a large connectome database (N=1,000). Circuits associated with improvement in each depression symptom were identified and then clustered based on similarity. The authors tested for reproducibility across data sets and whether symptom-specific targets derived from one data set could predict symptom improvement in the other independent cohort.

RESULTS

The authors identified two distinct circuit targets effective for two discrete clusters of depressive symptoms. Dysphoric symptoms, such as sadness and anhedonia, responded best to stimulation of one circuit, while anxiety and somatic symptoms responded best to stimulation of a different circuit. These circuit maps were reproducible, predicted symptom improvement in independent patient cohorts, and were specific to active compared with sham stimulation. The maps predicted symptom improvement in an exploratory analysis of stimulation sites from 14 clinical TMS trials.

CONCLUSIONS

Distinct clusters of depressive symptoms responded better to different TMS targets across independent retrospective data sets. These symptom-specific targets can be prospectively tested in a randomized clinical trial. This data-driven approach for identifying symptom-specific targets may prove useful for other disorders and facilitate personalized neuromodulation therapy.