Specific Phobia
Conditions
Brief summary
The aim of the present study is to determine whether people receiving d-cycloserine and exposure therapy show different brain reactions to symptom provocation compared to people receiving placebo and exposure therapy.
Detailed description
D-cycloserine (DCS) is a partial N-methyl-D-aspartate (NMDA) receptor agonist that may improve or accelerate extinction learning. We will randomly assign people with snake phobia to receive DCS or placebo, and then provide all participants with exposure therapy. We will examine whether people receiving DCS and vs. placebo show different brain reactions to symptom provocation before and after exposure therapy.
Interventions
DRUGD-cycloserine
50 mg d-cycloserine, oral, 1 dose
BEHAVIORALExposure therapy
Single session graded in vivo exposure therapy, 60-180 minutes
DRUGPlacebo
Single capsule of oral placebo, administered once 1 hr prior to exposure therapy
Sponsors
Hartford Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Caregiver, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
* Primary diagnosis of specific phobia (snakes)
Exclusion criteria
* History of psychosis, obsessive-compulsive disorder, or mania * Recent substance abuse or suicidality * Previous receipt of study treatments
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Snake Questionnaire (SNAQ) | 2 weeks | 30-item self-report scale of severity of snake fear and avoidance Range: 0-30; higher values indicate greater fear severity |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Clinician's Global Impression (CGI)-Improvement | 2 weeks | Clinician rating of global illness severity (at post-treatment) CGI-Improvement range 1-7; higher scores indicate poorer improvement; classified as responder if score = 1 or 2, nonresponder if score \> 2 |
| Clinician's Global Impression (CGI)-Severity | 2 weeks | Clinician rating of global illness severity (at pre- and post-treatment) CGI-Severity range 1-7; higher scores indicate greater illness severity. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| D-cycloserine Plus Exposure Therapy Single session (up to 3 hr) of in vivo exposure therapy plus 50 mg oral d-cycloserine administered 1 hr prior to exposure therapy session | 10 |
| Placebo Plus Exposure Therapy Single session (up to 3 hr) of in vivo exposure therapy plus oral placebo capsule administered 1 hr prior to exposure therapy session | 10 |
| Total | 20 |
Baseline characteristics
| Characteristic | Placebo Plus Exposure Therapy | D-cycloserine Plus Exposure Therapy | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 10 Participants | 10 Participants | 20 Participants |
| Age, Continuous | 34.6 years STANDARD_DEVIATION 12.69 | 39 years STANDARD_DEVIATION 13.91 | 37 years STANDARD_DEVIATION 13 |
| Region of Enrollment United States | 10 participants | 10 participants | 20 participants |
| Sex: Female, Male Female | 6 Participants | 6 Participants | 12 Participants |
| Sex: Female, Male Male | 4 Participants | 4 Participants | 8 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 1 / 10 | 0 / 10 |
| serious Total, serious adverse events | 0 / 10 | 0 / 10 |
Outcome results
Primary
Snake Questionnaire (SNAQ)
30-item self-report scale of severity of snake fear and avoidance Range: 0-30; higher values indicate greater fear severity
Time frame: 2 weeks
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| D-cycloserine Plus Exposure Therapy | Snake Questionnaire (SNAQ) | 9.6 units on a scale | Standard Deviation 5.99 |
| Placebo Plus Exposure Therapy | Snake Questionnaire (SNAQ) | 9.7 units on a scale | Standard Deviation 6.18 |
Secondary
Clinician's Global Impression (CGI)-Improvement
Clinician rating of global illness severity (at post-treatment) CGI-Improvement range 1-7; higher scores indicate poorer improvement; classified as responder if score = 1 or 2, nonresponder if score \> 2
Time frame: 2 weeks
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| D-cycloserine Plus Exposure Therapy | Clinician's Global Impression (CGI)-Improvement | 8 participants |
| Placebo Plus Exposure Therapy | Clinician's Global Impression (CGI)-Improvement | 9 participants |
Secondary
Clinician's Global Impression (CGI)-Severity
Clinician rating of global illness severity (at pre- and post-treatment) CGI-Severity range 1-7; higher scores indicate greater illness severity.
Time frame: 2 weeks
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| D-cycloserine Plus Exposure Therapy | Clinician's Global Impression (CGI)-Severity | 3 units on a scale | Standard Deviation 1.15 |
| Placebo Plus Exposure Therapy | Clinician's Global Impression (CGI)-Severity | 2.7 units on a scale | Standard Deviation 0.68 |