Clinical research challenges posed by difficult-to-treat depression.

Approximately one-third of individuals in a major depressive episode will not achieve sustained remission despite multiple, well-delivered treatments. These patients experience prolonged suffering and disproportionately utilize mental and general health care resources. The recently proposed clinical heuristic of 'difficult-to-treat depression' (DTD) aims to broaden our understanding and focus attention on the identification, clinical management, treatment selection, and outcomes of such individuals. Clinical trial methodologies developed to detect short-term therapeutic effects in treatment-responsive populations may not be appropriate in DTD. This report reviews three essential challenges for clinical intervention research in DTD: (1) how to define and subtype this heterogeneous group of patients; (2) how, when, and by what methods to select, acquire, compile, and interpret clinically meaningful outcome metrics; and (3) how to choose among alternative clinical trial design options to promote causal inference and generalizability. The boundaries of DTD are uncertain, and an evidence-based taxonomy and reliable assessment tools are preconditions for clinical research and subtyping. Traditional outcome metrics in treatment-responsive depression may not apply to DTD, as they largely reflect the only short-term symptomatic change and do not incorporate durability of benefit, side effect burden, or sustained impact on quality of life or daily function. The trial methodology will also require modification as trials will likely be of longer duration to examine the sustained impact, raising complex issues regarding control group selection, blinding and its integrity, and concomitant treatments.

Daily left prefrontal transcranial magnetic stimulation therapy for major depressive disorder: a sham-controlled randomized trial.

CONTEXT: Daily left prefrontal repetitive transcranial magnetic stimulation (rTMS) has been studied as a potential treatment for depression, but previous work had mixed outcomes and did not adequately mask sham conditions. OBJECTIVE: To test whether daily left prefrontal rTMS safely and effectively treats major depressive disorder. DESIGN: Prospective, multisite, randomized, active sham-controlled (1:1 randomization), duration-adaptive design with 3 weeks of daily weekday treatment (fixed-dose phase) followed by continued blinded treatment for up to another 3 weeks in improvers. SETTING: Four US university hospital clinics. PATIENTS: Approximately 860 outpatients were screened, yielding 199 antidepressant drug-free patients with unipolar nonpsychotic major depressive disorder. INTERVENTION: We delivered rTMS to the left prefrontal cortex at 120% motor threshold (10 Hz, 4-second train duration, and 26-second intertrain interval) for 37.5 minutes (3000 pulses per session) using a figure-eight solid-core coil. Sham rTMS used a similar coil with a metal insert blocking the magnetic field and scalp electrodes that delivered matched somatosensory sensations. MAIN OUTCOME MEASURE: In the intention-to-treat sample (n = 190), remission rates were compared for the 2 treatment arms using logistic regression and controlling for site, treatment resistance, age, and duration of the current depressive episode. RESULTS: Patients, treaters, and raters were effectively masked. Minimal adverse effects did not differ by treatment arm, with an 88% retention rate (90% sham and 86% active). Primary efficacy analysis revealed a significant effect of treatment on the proportion of remitters (14.1% active rTMS and 5.1% sham) (P = .02). The odds of attaining remission were 4.2 times greater with active rTMS than with sham (95% confidence interval, 1.32-13.24). The number needed to treat was 12. Most remitters had low antidepressant treatment resistance. Almost 30% of patients remitted in the open-label follow-up (30.2% originally active and 29.6% sham). CONCLUSION: Daily left prefrontal rTMS as monotherapy produced statistically significant and clinically meaningful antidepressant therapeutic effects greater than sham. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00149838.

Combined treatment with sertraline and liothyronine in major depression: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Antidepressant treatments that achieve a higher remission rate than those currently available are urgently needed. The thyroid hormone triiodothyronine may potentiate antidepressant effects. OBJECTIVE: To determine the antidepressant efficacy and safety of liothyronine sodium (triiodothyronine) when administered concurrently with the selective serotonin reuptake inhibitor sertraline hydrochloride to patients with major depressive disorder. DESIGN: Double-blind, randomized, 8-week, placebo-controlled trial. SETTING: Outpatient referral centers. PATIENTS: A total of 124 adult outpatients meeting unmodified DSM-IV criteria for major depressive disorder without psychotic features. INTERVENTIONS: Patients were randomized to receive sertraline hydrochloride (50 mg/d for 1 week; 100 mg/d thereafter) plus liothyronine sodium (20-25 microg/d for 1 week; 40-50 microg/d thereafter) or sertraline plus placebo for 8 weeks. MAIN OUTCOME MEASURES: The primary outcome measure was categorical response to treatment (> or =50% decrease in scores on the 21-item Hamilton Rating Scale for Depression from baseline to study end point). Remission rate (final Hamilton Rating Scale for Depression score, < or =6) was a secondary outcome measure. RESULTS: Intent-to-treat Hamilton Rating Scale for Depression response rates were 70% and 50% in the sertraline-liothyronine and sertraline-placebo groups, respectively (P = .02; odds ratio, 2.93; 95% confidence interval, 1.23-7.35); remission rates were 58% with sertraline-liothyronine and 38% with sertraline-placebo (P = .02; odds ratio, 2.69; 95% confidence interval, 1.16-6.49). Baseline T(3) values were lower in patients treated with sertraline-liothyronine who had remissions than in those without remissions (t(48) = 3.36; P<.002). Among patients treated with sertraline-liothyronine, remission was associated with a significant decrease in serum thyrotropin values (F(1,73) = 4.00; P<.05). There were no significant effects of liothyronine supplementation on frequency of adverse effects. CONCLUSIONS: These results demonstrate enhancement of the antidepressant effect of sertraline by concurrent treatment with liothyronine without a significant increase in adverse effects. The antidepressant effect of liothyronine may be directly linked to thyroid function.

Durability of antidepressant response to vagus nerve stimulation (VNS).

This study characterized the durability of improvement in patients who responded early or late while receiving vagus nerve stimulation (VNS). In both a pilot and pivotal study, patients were identified who had at least a 50% reduction in symptom scores 3 months (early responders) or 12 months (late responders) after starting VNS. Probabilities were determined for maintenance of response at 12-month and 24-month time-points. Consistency of improvement throughout the 24-month study period was evaluated, testing for change in serial depression ratings. In the pilot study, 30.5%, 23.7% and 45.8% were early responders, later responders, and non-responders, respectively. These rates were 14.6%, 19.5%, and 65.9% in the pivotal trial. The potential confound of alterations in antidepressant treatment was examined in the pivotal trial. In the pilot study, 72.2% and 61.1% of early responders (n=18) were responders at 12 and 24 months, respectively; 78.8% of late responders (n=14) were responders at 24 months. In the pivotal trial, of early responders (n=30), 63.3% and 76.7% maintained response at 12 and 24 months, respectively; of late responders (n=40), 65.0% maintained response at 24 months. Early and late responders had fewer changes in medication than non-responders across the pivotal study period. In both studies, analyses of serial depression ratings showed stable improvement in early and late responders. These samples had exceptional levels of chronicity and treatment resistance. Yet patients who showed substantial clinical benefit maintained the improvement at remarkably high rates. This durability of benefit was not attributable to alterations in other treatments.

Two-year outcome of vagus nerve stimulation (VNS) for treatment of major depressive episodes.

BACKGROUND: Vagus nerve stimulation (VNS) had antidepressant effects in an initial open, acute phase pilot study of 59 participants in a treatment-resistant major depressive episode (MDE). We examined the effects of adjunctive VNS over 24 months in this cohort. METHOD: Adult outpatients (N = 59) with chronic or recurrent major depressive disorder or bipolar (I or II) disorder and experiencing a treatment-resistant, nonpsychotic MDE (DSM-IV criteria) received 2 years of VNS. Changes in psychotropic medications and VNS stimulus parameters were allowed only after the first 3 months. Response was defined as > or = 50% reduction from the baseline 28-item Hamilton Rating Scale for Depression (HAM-D-28) total score, and remission was defined as a HAM-D-28 score < or = 10. RESULTS: Based on last observation carried forward analyses, HAM-D-28 response rates were 31% (18/59) after 3 months, 44% (26/59) after 1 year, and 42% (25/59) after 2 years of adjunctive VNS. Remission rates were 15% (9/59) at 3 months, 27% (16/59) at 1 year, and 22% (13/59) at 2 years. By 2 years, 2 deaths (unrelated to VNS) had occurred, 4 participants had withdrawn from the study, and 81% (48/59) were still receiving VNS. Longer-term VNS was generally well tolerated. CONCLUSION: These results suggest that patients with chronic or recurrent, treatment-resistant depression may show long-term benefit when treated with VNS.

Vagus nerve stimulation for treatment-resistant depression: a randomized, controlled acute phase trial.

BACKGROUND: Vagus nerve stimulation (VNS) alters both concentrations of neurotransmitters or their metabolites and functional activity of central nervous system regions dysregulated in mood disorders. An open trial has suggested efficacy. METHODS: This 10-week, acute, randomized, controlled, masked trial compared adjunctive VNS with sham treatment in 235 outpatients with nonpsychotic major depressive disorder (n = 210) or nonpsychotic, depressed phase, bipolar disorder (n = 25). In the current episode, participants had not responded adequately to between two and six research-qualified medication trials. A two-week, single-blind recovery period (no stimulation) and then 10 weeks of masked active or sham VNS followed implantation. Medications were kept stable. Primary efficacy outcome among 222 evaluable participants was based on response rates (>/=50% reduction from baseline on the 24-item Hamilton Rating Scale for Depression [HRSD(24)]). RESULTS: At 10-weeks, HRSD(24) response rates were 15.2% for the active (n = 112) and 10.0% for the sham (n = 110) groups (p = .251, last observation carried forward [LOCF]). Response rates with a secondary outcome, the Inventory of Depressive Symptomatology - Self-Report (IDS-SR(30)), were 17.0% (active) and 7.3% (sham) (p = .032, LOCF). VNS was well tolerated; 1% (3/235) left the study because of adverse events. CONCLUSIONS: This study did not yield definitive evidence of short-term efficacy for adjunctive VNS in treatment-resistant depression.

Effects of 12 months of vagus nerve stimulation in treatment-resistant depression: a naturalistic study.

BACKGROUND: The need for effective, long-term treatment for recurrent or chronic, treatment-resistant depression is well established. METHODS: This naturalistic follow-up describes outpatients with nonpsychotic major depressive (n = 185) or bipolar (I or II) disorder, depressed phase (n = 20) who initially received 10 weeks of active (n = 110) or sham vagus nerve stimulation (VNS) (n = 95). The initial active group received another 9 months, while the initial sham group received 12 months of VNS. Participants received antidepressant treatments and VNS, both of which could be adjusted. RESULTS: The primary analysis (repeated measures linear regression) revealed a significant reduction in 24-item Hamilton Rating Scale for Depression (HRSD(24)) scores (average improvement, .45 points [SE = .05] per month (p < .001). At exit, HRSD(24) response rate was 27.2% (55/202); remission rate (HRSD(24) < or = 9) was 15.8% (32/202). Montgomery Asberg Depression Rating Scale (28.2% [57/202]) and Clinical Global Impression-Improvement (34.0% [68/200]) showed similar response rates. Voice alteration, dyspnea, and neck pain were the most frequently reported adverse events. CONCLUSIONS: These 1-year open trial data found VNS to be well tolerated, suggesting a potential long-term, growing benefit in treatment-resistant depression, albeit in the context of changes in depression treatments. Comparative long-term data are needed to determine whether these benefits can be attributed to VNS.

A one-year comparison of vagus nerve stimulation with treatment as usual for treatment-resistant depression.

BACKGROUND: Previous reports have described the effects of vagus nerve stimulation plus treatment as usual (VNS+TAU) during open trials of patients with treatment-resistant depression (TRD). To better understand these effects on long-term outcome, we compared 12-month VNS+TAU outcomes with those of a comparable TRD group. METHODS: Admission criteria were similar for those receiving VNS+TAU (n = 205) or only TAU (n = 124). In the primary analysis, repeated-measures linear regression was used to compare the VNS+TAU group (monthly data) with the TAU group (quarterly data) according to scores of the 30-item Inventory of Depressive Symptomatology-Self-Report (IDS-SR(30)). RESULTS: The two groups had similar baseline demographic data, psychiatric and treatment histories, and degrees of treatment resistance, except that more TAU participants had at least 10 prior major depressive episodes, and the VNS+TAU group had more electroconvulsive therapy before study entry. Vagus nerve stimulation plus treatment as usual was associated with greater improvement per month in IDS-SR(30) than TAU across 12 months (p < .001). Response rates according to the 24-item Hamilton Rating Scale for Depression (last observation carried forward) at 12 months were 27% for VNS+TAU and 13% for TAU (p < .011). Both groups received similar TAU (drugs and electroconvulsive therapy) during follow-up. CONCLUSIONS: This comparison of two similar but nonrandomized TRD groups showed that VNS+TAU was associated with a greater antidepressant benefit over 12 months.

Absence of histological lesions in primate models of ECT and magnetic seizure therapy.

OBJECTIVE: The authors present preliminary findings from the first nonhuman primate neuropathological study of ECT to use perfusion fixation and adequate controls and the first to compare ECT with magnetic seizure therapy, to their knowledge. METHOD: Twelve Macaca mullata received 6 weeks of daily ECT, magnetic seizure therapy, or anesthesia alone. After perfusion fixation, their brains were examined while masked to intervention. RESULTS: No identified lesions were attributable to the interventions. Cortical and hippocampal immunoreactivity for glial fibrillary acidic protein (an astrocytic marker) was most intense in the group that received ECT. CONCLUSIONS: This small but rigorous primate study supports the view that ECT does not produce histological lesions in the brain and provides the first comparable safety data on magnetic seizure therapy.

New developments in electroconvulsive therapy and magnetic seizure therapy.

New findings regarding the mechanisms of action of electro-convulsive therapy (ECT) have led to novel developments in treatment technique to further improve this highly effective treatment for major depression. These new approaches include novel placements, optimization of electrical stimulus parameters, and new methods for inducing more targeted seizures(eg, magnetic seizure therapy [MST]). MST is the use of transcranial magnetic stimulation to induce a seizure. Magnetic fields pass through tissue unimpeded, providing more control over the site and extent of stimulation than can be achieved with ECT. This enhanced control represents a means of focusing the treatment on target cortical structures thought to be essential to antidepressant response and reducing spread to medial temporal regions implicated in the cognitive side effects of ECT. MST is at an early stage of development. Preliminary results suggest that MST may have some advantages over ECT in terms of subjective side effects and acute cognitive functioning. Studies designed to address the antidepressant efficacy of MST are underway. As with all attempts to improve convulsive therapy technique, the clinical value of MST will need to be established through controlled clinical trials. This article reviews the experience to date with MST, and places this work in the broader context of other means of optimizing convulsive therapy in the treatment of depression.

Background and rationale for the sequenced treatment alternatives to relieve depression (STAR*D) study.

Sequenced Treatment Alternatives to Relieve Depression (STAR*D) attempts to fill in major clinical information gaps and to evaluate the theoretical principles and clinical beliefs that currently guide pharmacotherapy of major depressive disorder. The study is conducted in representative participant groups and settings using clinical management tools that easily can be applied in daily practice. Outcomes include clinical outcomes and health care utilization and cost estimates. Research findings should be immediately applicable to, and easily implemented in, the daily primary and specialty care practices. This article provides the overall rationale for STAR*D and details the rationale for key design, measurement, and analytic features of the study.

Vagus nerve stimulation (VNS) for major depressive episodes: one year outcomes.

BACKGROUND: Vagus nerve stimulation has shown promising results in an open, acute phase pilot study of adults in a treatment-resistant major depressive episode. This open, naturalistic follow-up study was conducted to determine whether the initial promising effects were sustained, and whether changes in function would be observed. METHODS: Thirty adult outpatients in a treatment-resistant, nonpsychotic major depressive episode received an additional 9 months of vagus nerve stimulation treatment following exit from the 3-month acute study. Changes in psychotropic medications and vagus nerve stimulation stimulus parameters were allowed during this longer-term follow-up study. A priori definitions were used to define response (> or = 50% reduction in baseline Hamilton Rating Scale for Depression total score) and remission (Hamilton Rating Scale for Depression < or = 10). RESULTS: The response rate was sustained [40% (12/30) to 46% (13/28); p =.317] and the remission rate significantly increased [17% (5/30) to 29% (8/28); p =.045] with an additional 9 months of long-term vagus nerve stimulation treatment after exit from the acute study (1 year total vagus nerve stimulation treatment). Significant improvements in function between acute study exit and the 1-year follow-up assessment as measured by the Medical Outcomes Study Short Form-36 were observed. CONCLUSIONS: Longer-term vagus nerve stimulation treatment was associated with sustained symptomatic benefit and sustained or enhanced functional status in this naturalistic follow-up study.