Height PhobiaPhase 2NCT01037101
D-Cycloserine-Enhancer of One-Session Treatment for Phobia of Heights
A Phase 2 study testing In Vivo Exposure Therapy, Virtual Reality Exposure Therapy and D-Cycloserine in people with Height Phobia, run by CAMC Health System at 1 site in United States.
Trial summary
The study will determine the effects of D-Cycloserine (DCS) on fear reduction in patients diagnosed with phobia of heights (acrophobia) undergoing one session of three hours of virtual reality exposure therapy (VRET) or in vivo exposure therapy (IVET). Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Height Phobia
- What is being tested?
- In Vivo Exposure Therapy, Virtual Reality Exposure Therapy and D-Cycloserine
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 4 participants
- Where
- 1 siteUnited States
- Study dates
- 10 Jul 2009to 27 Jun 2017
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age between 18 and 65 years
- Men and women
- Diagnosis of acrophobia based on a clinical interview (ADIS-IV)
- Must sign an informed consent document after complete explanation of the study documenting that they understand the purpose of the study, procedures to be undertaken, possible benefits, potential risks, and are willing to participate.
Who cannot join
- A lifetime history of bipolar disorder, schizophrenia, psychosis, delusional disorders; organic brain syndrome, cognitive dysfunction that could interfere with capacity to engage in therapy;
- A history of substance or alcohol dependence (other than nicotine) in the last 6 months or otherwise unable to commit to refraining from alcohol use during the period of study participation.
- Patients with significant suicidal ideation or who have enacted suicidal behaviors within 6 months prior to intake will be excluded from study participation and referred for appropriate services.
- Patients must be off concurrent anxiolytics and beta blockers and on a stable dose of antidepressant medication for at least 3 weeks prior to initiation of randomized treatment.
- Patients receiving medication that might interfere with study medication (medication that might lower seizure threshold: meperidine or antibiotics in high dosage: penicillins, cephalosporins, amphotericin and imipenem),
- Patients with a current or past history of seizures
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- Pregnant women, lactating women, and women of childbearing potential who are not using medically accepted effective methods of contraception or abstinence
- Patients with a history of renal insufficiency (creatinine clearance less than 60 mL/min) or liver insufficiency
- Any concurrent psychotherapy initiated within 3 months of baseline, or ongoing psychotherapy of any duration specifically targeting phobias
- Patients unable to understand study procedures and participate in the informed consent process.
- Other serious medical illnesses (e.g., cardiovascular, liver, kidney, respiratory, endocrine, neurologic, or blood-related diseases),
- Inability to tolerate wearing the Virtual Reality Head Mounted Display,
- If patients refuse the study medication
- Any allergic reactions to D-Cycloserine by history
Trial locations and contacts
1 site in 1 country.
United States1 site
West Virginia University School of Medicine Charleston Division
Charleston, West Virginia, 25304
About this study
Official title: D-Cycloserine as Enhancer of One-Session Treatment for Phobia of Heights in Adults
The study will determine the effects of D-Cycloserine (DCS) on fear reduction in patients diagnosed with phobia of heights (acrophobia) undergoing one session of three hours of virtual reality exposure therapy (VRET) or in vivo exposure therapy (IVET).
Read the detailed description
The impact of D-Cycloserine on Virtual Reality Exposure Therapy (VRET) and In Vivo Exposure Therapy (IVET) for phobia of heights (acrophobia) will be tested using a randomized, double-blind, placebo-controlled trial. Eighty participants will be randomly assigned to one of the four treatment conditions: one-session VRET (3 hours) and 50 mg D-Cycloserine (VR-OST + DCS, N1=20); one-session VRET (3 hours) and placebo (VR-OST + Pl, N2=20); one-session IVET (3 hours) and placebo (IV + Pl, N3=20); or one-session IVET (3 hours) and 50 mg D-Cycloserine, (IV + DCS, N4=20). For twenty participants (5 from each group) the treatment will be delayed for three weeks and an additional assessment will be conducted as they will comprise a Wait List (WL) control group. Behavioral, cognitive and physiological changes in acrophobia will be assessed at pre-treatment, post-waitlist, post-treatment and 3 months follow-up.
- Conditions
- Height Phobia
- Being tested
- In Vivo Exposure Therapy, Virtual Reality Exposure Therapy, D-Cycloserine, Placebo
- Keywords
- acrophobia, virtual reality, exposure therapy, In Vivo Exposure Therapy plus D-Cycloserine, In Vivo Exposure Therapy plus Placebo, Virtual Reality Exposure Therapy plus D-Cycloserine, Virtual Reality Exposure Therapy plus Placebo, Wait-List
- Medical subject headings
- Acrophobia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
In Vivo Exposure TherapyBehavioural
Three hours of exposure therapy in a high place
Virtual Reality Exposure TherapyBehavioural
Three hours of exposure therapy using a virtual reality system
D-CycloserineDrug
Also called Seromycin
50 mg of DCS administered 30 minutes before the session
PlaceboDrug
50 mg placebo administered 30 minutes before the session
| Study group | Role | What they receive |
|---|---|---|
| IVET+DCS | Active comparator | Not described Receives: Behavioral: In Vivo Exposure Therapy; Drug: D-Cycloserine |
| VRET+DCS | Experimental | Not described Receives: Behavioral: Virtual Reality Exposure Therapy; Drug: D-Cycloserine |
| VRET+Placebo | Experimental | Not described Receives: Behavioral: Virtual Reality Exposure Therapy; Drug: Placebo |
| IVET+Placebo | Active comparator | Not described Receives: Behavioral: In Vivo Exposure Therapy; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Specific Phobia (Acrophobia) Diagnosed Based on Anxiety Disorders Interview Schedule - IV (ADIS-IV)
Presence or absence of a diagnosis of specific phobia (acrophobia) as assessed using the Anxiety Disorders Interview Schedule-IV (ADIS-IV).
Measured: One-week post-treatment and 3-months follow-up
Secondary outcomes (3)
Physiological Responses to Phobia-related Stimuli, Percentage of Steps Completed and Subjective Units of Distress During a Behavioral Avoidance Test (BAT)
Physiological responses to phobia-related stimuli, percentage of steps completed and Subjective Units of Distress during a Behavioral Avoidance Test (BAT) - Study was terminated due to lack of enrollment and outcome data are unavailable
Measured: One-week post-treatment and 3-months follow-up
Number of Steps Completed During the Behavioral Analysis Test (BAT)
Number of steps completed during exposure to the feared stimulus. Higher numbers will indicate greater completion of the BAT procedure at the assessment
Measured: One-week post-treatment and 3-months follow-up
Subjective Units of Distress (SUDS) During BAT
Participant-supported SUDS ratings to be obtained during BAT to assess distress associated with exposure to the feared stimulus
Measured: One-week post-treatment and 3-months follow-up
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Dec 2009 (estimated)
- Study start10 Jul 2009
- Primary completion21 Feb 2012
- Study completion27 Jun 2017
Why it stopped: Lack of enrollment, 5 completed by 2011 however no further enrollment took place until study terminated in 2017.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Height PhobiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 4 participants (actual)
Sponsor and investigators
- Lead sponsor
- CAMC Health System
- Sponsor type
- University, hospital or other
- Collaborators
- West Virginia University, University of Charleston
- Responsible party
- Sponsor
- Investigators
- Cristian Sirbu, Ph.D., Principal investigator, CAMC Health System
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01037101
- Sponsor's protocol ID
- 07-01-1896
- Status last verified
- Mar 2026
- First submitted
- 18 Dec 2009
- Last updated
- 22 Oct 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 22 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- D-Cycloserine as Enhancer of One-Session Treatment for Phobia of Heights in Adults
- ClinicalTrials.gov ID
- NCT01037101
- Acronym / sponsor ID
- 07-01-1896
- Conditions
- Height Phobia
- Keywords
- acrophobia, virtual reality, exposure therapy, In Vivo Exposure Therapy plus D-Cycloserine, In Vivo Exposure Therapy plus Placebo, Virtual Reality Exposure Therapy plus D-Cycloserine, Virtual Reality Exposure Therapy plus Placebo, Wait-List
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Lack of enrollment, 5 completed by 2011 however no further enrollment took place until study terminated in 2017.
- Enrolment
- 4 participants (actual)
- Lead sponsor
- CAMC Health SystemUniversity, hospital or other
- Collaborators
- West Virginia University, University of Charleston
- Study start
- 10 Jul 2009 (actual)
- Primary completion
- 21 Feb 2012 (actual)
- Study completion
- 27 Jun 2017 (actual)
- First posted
- 21 Dec 2009 (estimated)
- Results
- Posted 22 Oct 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The study will determine the effects of D-Cycloserine (DCS) on fear reduction in patients diagnosed with phobia of heights (acrophobia) undergoing one session of three hours of virtual reality exposure therapy (VRET) or in vivo exposure therapy (IVET).
Detailed description
The impact of D-Cycloserine on Virtual Reality Exposure Therapy (VRET) and In Vivo Exposure Therapy (IVET) for phobia of heights (acrophobia) will be tested using a randomized, double-blind, placebo-controlled trial. Eighty participants will be randomly assigned to one of the four treatment conditions: one-session VRET (3 hours) and 50 mg D-Cycloserine (VR-OST + DCS, N1=20); one-session VRET (3 hours) and placebo (VR-OST + Pl, N2=20); one-session IVET (3 hours) and placebo (IV + Pl, N3=20); or one-session IVET (3 hours) and 50 mg D-Cycloserine, (IV + DCS, N4=20). For twenty participants (5 from each group) the treatment will be delayed for three weeks and an additional assessment will be conducted as they will comprise a Wait List (WL) control group. Behavioral, cognitive and physiological changes in acrophobia will be assessed at pre-treatment, post-waitlist, post-treatment and 3 months follow-up.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| IVET+DCS | Active comparator | Behavioral: In Vivo Exposure Therapy, Drug: D-Cycloserine |
| VRET+DCS | Experimental | Behavioral: Virtual Reality Exposure Therapy, Drug: D-Cycloserine |
| VRET+Placebo | Experimental | Behavioral: Virtual Reality Exposure Therapy, Drug: Placebo |
| IVET+Placebo | Active comparator | Behavioral: In Vivo Exposure Therapy, Drug: Placebo |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Age between 18 and 65 years
- Men and women
- Diagnosis of acrophobia based on a clinical interview (ADIS-IV)
- Must sign an informed consent document after complete explanation of the study documenting that they understand the purpose of the study, procedures to be undertaken, possible benefits, potential risks, and are willing to participate.
Key exclusion criteria (14 listed)
- A lifetime history of bipolar disorder, schizophrenia, psychosis, delusional disorders; organic brain syndrome, cognitive dysfunction that could interfere with capacity to engage in therapy;
- A history of substance or alcohol dependence (other than nicotine) in the last 6 months or otherwise unable to commit to refraining from alcohol use during the period of study participation.
- Patients with significant suicidal ideation or who have enacted suicidal behaviors within 6 months prior to intake will be excluded from study participation and referred for appropriate services.
- Patients must be off concurrent anxiolytics and beta blockers and on a stable dose of antidepressant medication for at least 3 weeks prior to initiation of randomized treatment.
- Patients receiving medication that might interfere with study medication (medication that might lower seizure threshold: meperidine or antibiotics in high dosage: penicillins, cephalosporins, amphotericin and imipenem),
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| In Vivo Exposure TherapyThree hours of exposure therapy in a high place | Behavioural | IVET+DCS, IVET+Placebo |
| Virtual Reality Exposure TherapyThree hours of exposure therapy using a virtual reality system | Behavioural | VRET+DCS, VRET+Placebo |
| D-CycloserineAlso: Seromycin50 mg of DCS administered 30 minutes before the session | Drug | IVET+DCS, VRET+DCS |
| Placebo50 mg placebo administered 30 minutes before the session | Drug | IVET+Placebo, VRET+Placebo |
Primary outcome
Specific Phobia (Acrophobia) Diagnosed Based on Anxiety Disorders Interview Schedule - IV (ADIS-IV)
Time frame: One-week post-treatment and 3-months follow-up
Presence or absence of a diagnosis of specific phobia (acrophobia) as assessed using the Anxiety Disorders Interview Schedule-IV (ADIS-IV).
3 secondary outcomes
Physiological Responses to Phobia-related Stimuli, Percentage of Steps Completed and Subjective Units of Distress During a Behavioral Avoidance Test (BAT)
Time frame: One-week post-treatment and 3-months follow-up
Number of Steps Completed During the Behavioral Analysis Test (BAT)
Time frame: One-week post-treatment and 3-months follow-up
Subjective Units of Distress (SUDS) During BAT
Time frame: One-week post-treatment and 3-months follow-up
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Oct 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Cristian Sirbu, Ph.D. principal investigator
CAMC Health System
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing In Vivo Exposure Therapy, Virtual Reality Exposure Therapy and D-Cycloserine in people with Height Phobia, run by CAMC Health System at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 22 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 22 Oct 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Specific Phobia (Acrophobia) Diagnosed Based on Anxiety Disorders Interview Schedule - IV (ADIS-IV) (time frame: One-week post-treatment and 3-months follow-up). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Oct 2026.