Anxiety Disorder, Anxiety State
Conditions
Keywords
Threat Reversal, Emotion Flexibility
Brief summary
The goal of this clinical trial is to explore the flexibility of threat control and underlying neural mechanism based on the threat reversal paradigm (a highly validated new paradigm where threat learning and inhibition are required) in patients with anxiety disorders (mainly generalized anxiety disorder). The hypotheses are: 1. Threat reversal abilities are hypothesized to be impaired in patients with anxiety disorders compared to healthy normal subjects, which are assumed to be associated with anxiety symptoms. 2. The neural mechanism underlying threat reversal abnormalities in patients with anxiety disorders is hypothesized to involve the prefrontal cortex, amygdala, and hippocampus. 3. The repetitive stimulation to the core brain regions of threat reversal is assumed to improve threat reversal abilities and anxiety symptoms of patients.
Detailed description
In this study, there are three sub-trials in combination with skin conductance response (SCR), functional magnetic resonance imaging (fMRI), and non-invasive neuromodulation techniques to uncover the abnormal threat reversal in anxiety disorder at behavioral and neural levels. Participants in the first trial will learn the threat of emotional faces based on the Pavlovian conditioned fear learning paradigm; their neural activities in the hypothesized brain regions will be obtained via brain imaging equipment. The researchers will compare the differences among three groups (one patient group, two healthy control groups with different anxiety level) on performance in the threat reversal task, and their neural activities and brain functional connectivity characteristics, in order to reveal the potential behavioral threat reversal abnormalities and core associated brain regions underlying threat reversal. Participants in the second trial will be given the same learning paradigm and brain imaging equipment as in the first, but with repetitive stimulation intervention on the core brain regions determined in study 1. Using a double-blind randomized controlled experiment, the participants will be divided into three groups (active stimulation + patient, sham stimulation + patient, and sham stimulation + healthy control). The researchers will compare the behavioral differences in the threat reversal task after active and sham stimulation. Participants in the third trial will be given the same study design and intervention as the second trial, but for eight weeks. Finally, the researchers will retest and compare the improvement in threat reversal abilities and anxiety symptoms to see the long-term clinical effects of the intervention.
Interventions
DEVICEActive repetitive deep transcranial magnetic stimulation (dTMS)
Before the intervention, the brain structure of each participant will be captured using an MRI scanner, and individualized spatial coordinates of the hypothesized target will be determined based on these 3D structural images. Then the resting motor threshold will be tested using the method of thumb twitching observation. The intervention will employ the H7 coil that is accurately delivered to the intended target by an optic navigation and a deep pulse protocol at 90% of the tested threshold for 15-minute stimulation duration.
DEVICESham repetitive deep transcranial magnetic stimulation (dTMS)
Before the intervention, the brain structure of each participant will be captured using an MRI scanner, and individualized spatial coordinates of the hypothesized target will be determined based on these 3D structural images. Then the resting motor threshold will be tested using the method of thumb twitching observation. The intervention will employ the H7 coil that is placed on the scalp to mimic the sensation and sounds of the actual treatment but without letting the magnetic field reach the brain tissue for 15-minute duration.
Sponsors
The National Natural Science Foundation of China (NSFC)
Shenzhen Kangning Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
for patient participants: Clinical diagnosis of anxiety disorders (by psychiatrists using the structured clinical interview for DSM-IV-TR (SCID) with reference to the diagnostic criteria for GAD according to the ICD-10)
Exclusion criteria
for patient participants: 1. A history of serious cardiovascular, cerebrovascular diseases, stroke, or other neurological disorders, a history of gastrointestinal diseases. 2. Severe hearing or vision impairments. 3. Metallic implants in the body, such as non-removable dentures, stents, metal plates, joint metal replacements, etc. 4. Claustrophobia. 5. Acute or chronic diseases or infections. 6. Pregnancy or breastfeeding. 7. Smoking or drinking alcohol within 24 hours before the experiment. 8. Previous participation in similar experiments conducted by this institution. Inclusion Criteria for healthy control participants: 1. No physical diseases or mental disorders. 2. No claustrophobia. 3. No hereditary diseases. 4. No medication history or smoking history. 5. Females not pregnant and not in their menstrual period. 6. Normal vision or corrected vision, no smoking, drinking alcohol, or taking medication within 24 hours prior to the experiment. 7. No previous participation in similar experiments.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes in participants' skin conductance response (SCR) | Baseline; every week (assessed weekly up to 8 weeks from the date of last intervention session) | The level of SCR will be assessed for each experiment trial as the base-to-peak amplitude difference in skin conductance of the largest deflection (in micro-siemens; pS) in the 0.5-4.5-slatency window after stimulus onset. |
| Changes in the prefrontal cortex measured with fMRI | Baseline; once per week (assessed weekly up to 8 weeks from the date of last intervention session) | Changes in the difference in blood oxygenation level dependent (BOLD) signals in the prefrontal cortex before and after the intervention. |
| Changes in the amygdala measured with fMRI | Baseline; once per week (assessed weekly up to 8 weeks from the date of last intervention session) | Changes in the difference in blood oxygenation level dependent (BOLD) signals in the amygdala before and after the intervention. |
| Changes in the hippocampus measured with fMRI | Baseline; once per week (assessed weekly up to 8 weeks from the date of last intervention session) | Changes in the difference in blood oxygenation level dependent (BOLD) signals in the hippocampus before and after the intervention. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes in the Intolerance of Uncertainty Scale-12 (IUS-12) | Baseline; once per week (assessed weekly up to 8 weeks from the date of last intervention session); 3 months (assessed at the week after 3 months from the last intervention session) | The IUS measures individuals' emotional, cognitive, and behavioral responses or tolerance to uncertain situations, consisting 12 items. Each item is rated on a 5-point Likert scale, ranging from Not at all characteristic of me to Entirely characteristic of me. Higher summed total scores suggest a higher level of intolerance of uncertainty. |
| Changes in the Anxiety Sensitivity Index (ASI) | Baseline; once per week (assessed weekly up to 8 weeks from the date of last intervention session); 3 months (assessed at the week after 3 months from the last intervention session) | The ASI measures the extent to which individuals are sensitive to their own anxiety symptoms, consisting 12 items. Each item is rated on a 5-point Likert scale, ranging from Not at all characteristic of me to Entirely characteristic of me. Higher summed total scores indicate greater anxiety sensitivity. |
| Changes in the State-Trait Anxiety Scale (STAI) | Baseline; once per week (assessed weekly up to 8 weeks from the date of last intervention session); 3 months (assessed at the week after 3 months from the last intervention session) | The STAI assesses the current state of anxiety and relatively stable aspects of anxiety proneness, each subscale consisting of 20 items. Each item is rated on a 4-point Likert scale, ranging from Not at all to Very much. Higher summed scores in subscales indicate greater state anxiety and trait anxiety. |
Contacts
Primary ContactJingchu Hu, Dr.
Outcome results
None listed