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“The take-home message is that this proof-of-concept study opens up a new avenue of treatment research so that in the future, we may be able to provide our patients with safe and well-tolerated medications and enhance noninvasive brain stimulation treatments for depression,” senior author Alexander McGirr, MD, PhD, assistant professor of psychiatry, University of Calgary (Alta.), told this news organization.
“Once the safety and efficacy of this strategy have been confirmed with larger multisite studies, this could be deployed within existing health care infrastructure,” he said.
The study was published online in JAMA Psychiatry.
Synaptic plasticity
Repetitive transmagnetic stimulation (rTMS) and the more recently developed intermittent theta-burst stimulation (iTBS) are noninvasive brain stimulation modalities that have the largest evidence base in improving MDD. Although efficacious, an “unacceptable proportion of patients do not significantly improve” with these approaches, the authors write.
“We believe that iTBS improves depression through a process called synaptic plasticity, or how neurons adapt to stimulation, but we know that synaptic plasticity is impacted by the illness,” Dr. McGirr explained. This “could be the reason that only some patients benefit.”
One potential strategy to enhance neuroplasticity is to administer an adjunctive N-methyl D-aspartate (NMDA) receptor agonist during stimulation, since the NMDA receptor is a “key regulator of synaptic plasticity,” the authors state. In fact, synaptic plasticity with continuous and intermittent TBS is NMDA-receptor–dependent.
“DCS is an NMDA receptor partial agonist, and so at the low dose we used in our trial (100 mg), it can facilitate NMDA receptor signaling. The hypothesis was that pairing it with iTBS would enhance synaptic plasticity and clinical outcomes,” Dr. McGirr said.
The group’s previous research demonstrated that targeting the NMDA receptor with low-dose DCS “normalizes long-term motor cortex plasticity in individuals with MDD.” It also led to greater persistence of iTBS-induced changes compared to placebo.
However, “a demonstration that these physiological effects have an impact on treatment outcomes is lacking,” the authors note.
To address this gap, the researchers conducted a 4-week double-blind, placebo-controlled trial in which 50 participants (mean [standard deviation] age, 40.8 [13.4] years; 62% women) were randomly assigned on a 1:1 basis to receive either iTBS plus DCS or iTBS plus placebo (n = 25 per group) for the first 2 weeks of the trial, followed by iTBS without an adjunct for the third and fourth weeks.
Participants were required to be experiencing a major depressive episode and to have failed to respond to at least one adequate antidepressant trial or psychotherapy (but not more than four adequate antidepressant trials during the current episode).
Patients with acute suicidality, psychosis, recent substance use disorder, benzodiazepine use, seizures, unstable medical conditions, history of nonresponse to rTMS or electroconvulsive therapy, or comorbid psychiatric conditions, as well as those for whom psychotherapy was initiated within 3 months of enrollment or during the trial, were excluded.
Depression was measured by the Montgomery-Åsberg Depression Rating Scale (MADRS) (changes in score constituted the primary outcome) and the 17-item Hamilton Depression Rating Scale (17-HDRS).
“Secondary outcomes included clinical response, clinical remission, and Clinical Global Impression (CGI) scores,” the authors state.
“Promising” findings
Most participants in the iTBS plus placebo group were White (80%); 12% were Asian, and 8% were classified as “other.” A smaller proportion of participants in the iTBS plus DCS group were White (68%); the next smallest group was Asian (16%), followed by Hispanic (12%), and “other” (4%).
Participants presented with moderate-severe depressive symptoms, as measured by both the HRDS-17 and the MADRS. The placebo and intervention groups had similar scores at baseline. Resting motor threshold did not differ significantly between the groups, either at baseline or between the weeks with and without adjunctive treatment.
Greater improvements in MADRS scores were found in the intervention group than in the placebo groups (mean difference, –6.15 [95% confidence interval, –2.43 to –9.88]; Hedges g, 0.99 [0.34-1.62]).
A larger treatment effect was found after 4 weeks of treatment than after 2 weeks, although the adjuvant was present for the first 2 weeks. “We speculate that, despite ongoing iTBS, this reflects an erosion of the placebo effect, as 15 of 25 participants (60%) in the iTBS plus placebo group plateaued or had a worsening MADRS score, compared with 9 of 25 participants (36%) in the iTBS plus DCS group,” the authors write.
The intervention group showed higher rates of clinical response compared to the placebo group (73.9% vs. 29.3%, respectively), as well as higher rates of clinical remission (39.1% vs. 4.2%, respectively), as reflected in lower CGI-severity ratings and greater CGI-improvement ratings.
There were no serious adverse events during the trial.
The authors note several limitations, including the small sample size and the fact that participants received the adjunctive treatment for only 2 weeks. Longer treatment courses “require dedicated study.” And the short length of the trial (only 4 weeks) meant the difference between “treatment acceleration” and “treatment enhancement” could not be determined.
Nevertheless, the results are “promising” and suggest additional investigation into “intersectional approaches with other dosing regimens and precision medicine targeting approaches,” the authors state.
Synergistic approach
Commenting on the study, Scott Aaronson, MD, chief science officer, Institute for Advanced Diagnostics and Therapeutics, Sheppard Pratt, Towson, Md., called the findings “heartening.” He noted that the study “demonstrates a creative approach of combining an FDA-approved antibiotic with NMDA partial agonist activity – D-cycloserine – with a brief course of iTBS with the aim of enhancing the neuronal plasticity iTBS creates.”
Dr. Aaronson, who is also an adjunct professor at the University of Maryland, Baltimore, and was not involved with the study, added, “This is an early demonstration of the ability to further exploit neuronal changes from neurostimulation by synergistic use of a pharmacologic intervention.”
The study was supported in part by a Young Investigator Award from the Brain and Behavior Research Foundation and the Campus Alberta Innovates Program Chair in Neurostimulation. Dr. McGirr has a patent for PCT/CA2022/050839 pending with MCGRx Corp and is a shareholder of MCGRx Corp. The other authors’ disclosures are listed on the original article. Dr. Aaronson is a consultant for Neuronetics.
A version of this article first appeared on Medscape.com.
“The take-home message is that this proof-of-concept study opens up a new avenue of treatment research so that in the future, we may be able to provide our patients with safe and well-tolerated medications and enhance noninvasive brain stimulation treatments for depression,” senior author Alexander McGirr, MD, PhD, assistant professor of psychiatry, University of Calgary (Alta.), told this news organization.
“Once the safety and efficacy of this strategy have been confirmed with larger multisite studies, this could be deployed within existing health care infrastructure,” he said.
The study was published online in JAMA Psychiatry.
Synaptic plasticity
Repetitive transmagnetic stimulation (rTMS) and the more recently developed intermittent theta-burst stimulation (iTBS) are noninvasive brain stimulation modalities that have the largest evidence base in improving MDD. Although efficacious, an “unacceptable proportion of patients do not significantly improve” with these approaches, the authors write.
“We believe that iTBS improves depression through a process called synaptic plasticity, or how neurons adapt to stimulation, but we know that synaptic plasticity is impacted by the illness,” Dr. McGirr explained. This “could be the reason that only some patients benefit.”
One potential strategy to enhance neuroplasticity is to administer an adjunctive N-methyl D-aspartate (NMDA) receptor agonist during stimulation, since the NMDA receptor is a “key regulator of synaptic plasticity,” the authors state. In fact, synaptic plasticity with continuous and intermittent TBS is NMDA-receptor–dependent.
“DCS is an NMDA receptor partial agonist, and so at the low dose we used in our trial (100 mg), it can facilitate NMDA receptor signaling. The hypothesis was that pairing it with iTBS would enhance synaptic plasticity and clinical outcomes,” Dr. McGirr said.
The group’s previous research demonstrated that targeting the NMDA receptor with low-dose DCS “normalizes long-term motor cortex plasticity in individuals with MDD.” It also led to greater persistence of iTBS-induced changes compared to placebo.
However, “a demonstration that these physiological effects have an impact on treatment outcomes is lacking,” the authors note.
To address this gap, the researchers conducted a 4-week double-blind, placebo-controlled trial in which 50 participants (mean [standard deviation] age, 40.8 [13.4] years; 62% women) were randomly assigned on a 1:1 basis to receive either iTBS plus DCS or iTBS plus placebo (n = 25 per group) for the first 2 weeks of the trial, followed by iTBS without an adjunct for the third and fourth weeks.
Participants were required to be experiencing a major depressive episode and to have failed to respond to at least one adequate antidepressant trial or psychotherapy (but not more than four adequate antidepressant trials during the current episode).
Patients with acute suicidality, psychosis, recent substance use disorder, benzodiazepine use, seizures, unstable medical conditions, history of nonresponse to rTMS or electroconvulsive therapy, or comorbid psychiatric conditions, as well as those for whom psychotherapy was initiated within 3 months of enrollment or during the trial, were excluded.
Depression was measured by the Montgomery-Åsberg Depression Rating Scale (MADRS) (changes in score constituted the primary outcome) and the 17-item Hamilton Depression Rating Scale (17-HDRS).
“Secondary outcomes included clinical response, clinical remission, and Clinical Global Impression (CGI) scores,” the authors state.
“Promising” findings
Most participants in the iTBS plus placebo group were White (80%); 12% were Asian, and 8% were classified as “other.” A smaller proportion of participants in the iTBS plus DCS group were White (68%); the next smallest group was Asian (16%), followed by Hispanic (12%), and “other” (4%).
Participants presented with moderate-severe depressive symptoms, as measured by both the HRDS-17 and the MADRS. The placebo and intervention groups had similar scores at baseline. Resting motor threshold did not differ significantly between the groups, either at baseline or between the weeks with and without adjunctive treatment.
Greater improvements in MADRS scores were found in the intervention group than in the placebo groups (mean difference, –6.15 [95% confidence interval, –2.43 to –9.88]; Hedges g, 0.99 [0.34-1.62]).
A larger treatment effect was found after 4 weeks of treatment than after 2 weeks, although the adjuvant was present for the first 2 weeks. “We speculate that, despite ongoing iTBS, this reflects an erosion of the placebo effect, as 15 of 25 participants (60%) in the iTBS plus placebo group plateaued or had a worsening MADRS score, compared with 9 of 25 participants (36%) in the iTBS plus DCS group,” the authors write.
The intervention group showed higher rates of clinical response compared to the placebo group (73.9% vs. 29.3%, respectively), as well as higher rates of clinical remission (39.1% vs. 4.2%, respectively), as reflected in lower CGI-severity ratings and greater CGI-improvement ratings.
There were no serious adverse events during the trial.
The authors note several limitations, including the small sample size and the fact that participants received the adjunctive treatment for only 2 weeks. Longer treatment courses “require dedicated study.” And the short length of the trial (only 4 weeks) meant the difference between “treatment acceleration” and “treatment enhancement” could not be determined.
Nevertheless, the results are “promising” and suggest additional investigation into “intersectional approaches with other dosing regimens and precision medicine targeting approaches,” the authors state.
Synergistic approach
Commenting on the study, Scott Aaronson, MD, chief science officer, Institute for Advanced Diagnostics and Therapeutics, Sheppard Pratt, Towson, Md., called the findings “heartening.” He noted that the study “demonstrates a creative approach of combining an FDA-approved antibiotic with NMDA partial agonist activity – D-cycloserine – with a brief course of iTBS with the aim of enhancing the neuronal plasticity iTBS creates.”
Dr. Aaronson, who is also an adjunct professor at the University of Maryland, Baltimore, and was not involved with the study, added, “This is an early demonstration of the ability to further exploit neuronal changes from neurostimulation by synergistic use of a pharmacologic intervention.”
The study was supported in part by a Young Investigator Award from the Brain and Behavior Research Foundation and the Campus Alberta Innovates Program Chair in Neurostimulation. Dr. McGirr has a patent for PCT/CA2022/050839 pending with MCGRx Corp and is a shareholder of MCGRx Corp. The other authors’ disclosures are listed on the original article. Dr. Aaronson is a consultant for Neuronetics.
A version of this article first appeared on Medscape.com.
“The take-home message is that this proof-of-concept study opens up a new avenue of treatment research so that in the future, we may be able to provide our patients with safe and well-tolerated medications and enhance noninvasive brain stimulation treatments for depression,” senior author Alexander McGirr, MD, PhD, assistant professor of psychiatry, University of Calgary (Alta.), told this news organization.
“Once the safety and efficacy of this strategy have been confirmed with larger multisite studies, this could be deployed within existing health care infrastructure,” he said.
The study was published online in JAMA Psychiatry.
Synaptic plasticity
Repetitive transmagnetic stimulation (rTMS) and the more recently developed intermittent theta-burst stimulation (iTBS) are noninvasive brain stimulation modalities that have the largest evidence base in improving MDD. Although efficacious, an “unacceptable proportion of patients do not significantly improve” with these approaches, the authors write.
“We believe that iTBS improves depression through a process called synaptic plasticity, or how neurons adapt to stimulation, but we know that synaptic plasticity is impacted by the illness,” Dr. McGirr explained. This “could be the reason that only some patients benefit.”
One potential strategy to enhance neuroplasticity is to administer an adjunctive N-methyl D-aspartate (NMDA) receptor agonist during stimulation, since the NMDA receptor is a “key regulator of synaptic plasticity,” the authors state. In fact, synaptic plasticity with continuous and intermittent TBS is NMDA-receptor–dependent.
“DCS is an NMDA receptor partial agonist, and so at the low dose we used in our trial (100 mg), it can facilitate NMDA receptor signaling. The hypothesis was that pairing it with iTBS would enhance synaptic plasticity and clinical outcomes,” Dr. McGirr said.
The group’s previous research demonstrated that targeting the NMDA receptor with low-dose DCS “normalizes long-term motor cortex plasticity in individuals with MDD.” It also led to greater persistence of iTBS-induced changes compared to placebo.
However, “a demonstration that these physiological effects have an impact on treatment outcomes is lacking,” the authors note.
To address this gap, the researchers conducted a 4-week double-blind, placebo-controlled trial in which 50 participants (mean [standard deviation] age, 40.8 [13.4] years; 62% women) were randomly assigned on a 1:1 basis to receive either iTBS plus DCS or iTBS plus placebo (n = 25 per group) for the first 2 weeks of the trial, followed by iTBS without an adjunct for the third and fourth weeks.
Participants were required to be experiencing a major depressive episode and to have failed to respond to at least one adequate antidepressant trial or psychotherapy (but not more than four adequate antidepressant trials during the current episode).
Patients with acute suicidality, psychosis, recent substance use disorder, benzodiazepine use, seizures, unstable medical conditions, history of nonresponse to rTMS or electroconvulsive therapy, or comorbid psychiatric conditions, as well as those for whom psychotherapy was initiated within 3 months of enrollment or during the trial, were excluded.
Depression was measured by the Montgomery-Åsberg Depression Rating Scale (MADRS) (changes in score constituted the primary outcome) and the 17-item Hamilton Depression Rating Scale (17-HDRS).
“Secondary outcomes included clinical response, clinical remission, and Clinical Global Impression (CGI) scores,” the authors state.
“Promising” findings
Most participants in the iTBS plus placebo group were White (80%); 12% were Asian, and 8% were classified as “other.” A smaller proportion of participants in the iTBS plus DCS group were White (68%); the next smallest group was Asian (16%), followed by Hispanic (12%), and “other” (4%).
Participants presented with moderate-severe depressive symptoms, as measured by both the HRDS-17 and the MADRS. The placebo and intervention groups had similar scores at baseline. Resting motor threshold did not differ significantly between the groups, either at baseline or between the weeks with and without adjunctive treatment.
Greater improvements in MADRS scores were found in the intervention group than in the placebo groups (mean difference, –6.15 [95% confidence interval, –2.43 to –9.88]; Hedges g, 0.99 [0.34-1.62]).
A larger treatment effect was found after 4 weeks of treatment than after 2 weeks, although the adjuvant was present for the first 2 weeks. “We speculate that, despite ongoing iTBS, this reflects an erosion of the placebo effect, as 15 of 25 participants (60%) in the iTBS plus placebo group plateaued or had a worsening MADRS score, compared with 9 of 25 participants (36%) in the iTBS plus DCS group,” the authors write.
The intervention group showed higher rates of clinical response compared to the placebo group (73.9% vs. 29.3%, respectively), as well as higher rates of clinical remission (39.1% vs. 4.2%, respectively), as reflected in lower CGI-severity ratings and greater CGI-improvement ratings.
There were no serious adverse events during the trial.
The authors note several limitations, including the small sample size and the fact that participants received the adjunctive treatment for only 2 weeks. Longer treatment courses “require dedicated study.” And the short length of the trial (only 4 weeks) meant the difference between “treatment acceleration” and “treatment enhancement” could not be determined.
Nevertheless, the results are “promising” and suggest additional investigation into “intersectional approaches with other dosing regimens and precision medicine targeting approaches,” the authors state.
Synergistic approach
Commenting on the study, Scott Aaronson, MD, chief science officer, Institute for Advanced Diagnostics and Therapeutics, Sheppard Pratt, Towson, Md., called the findings “heartening.” He noted that the study “demonstrates a creative approach of combining an FDA-approved antibiotic with NMDA partial agonist activity – D-cycloserine – with a brief course of iTBS with the aim of enhancing the neuronal plasticity iTBS creates.”
Dr. Aaronson, who is also an adjunct professor at the University of Maryland, Baltimore, and was not involved with the study, added, “This is an early demonstration of the ability to further exploit neuronal changes from neurostimulation by synergistic use of a pharmacologic intervention.”
The study was supported in part by a Young Investigator Award from the Brain and Behavior Research Foundation and the Campus Alberta Innovates Program Chair in Neurostimulation. Dr. McGirr has a patent for PCT/CA2022/050839 pending with MCGRx Corp and is a shareholder of MCGRx Corp. The other authors’ disclosures are listed on the original article. Dr. Aaronson is a consultant for Neuronetics.
A version of this article first appeared on Medscape.com.
FROM JAMA PSYCHIATRY