Contact information
Type
Scientific
Primary contact
Dr Sean Hood
ORCID ID
Contact details
School of Psychiatry and Clinical Neurosciences (M521)
Queen Elizabeth II Medical Centre
Nedlands
Perth
6009
Australia
+61 (0)8 93462393
sean@cyllene.uwa.edu.au
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
RA/4/1/1193
Study information
Scientific title
Acronym
Study hypothesis
Primary hypotheses:
1. Tryptophan depletion (TD) will cause transient symptom relapse in SSRI-remitted GAD patients, but only when challenged with the 7.5% CO2 provocation paradigm (Study 2)
2. OCD patients well on SSRIs will not relapse spontaneously when undergoing TD but will suffer a significant worsening of anxiety when exposed to a personalised phobic stimulus (Study 1)
Secondary hypotheses:
1. TD will have a greater impact upon women than men, according to primary outcome measures
2. Women will experience more nausea on the occasion that they have the tryptophan-restored (control) drink than on the tryptophan-depleted occasion
3. Transient depressive symptoms will be seen in subjects with a past history of depressive illness, despite the absence of a current or recent diagnosis of a depressive disorder
Ethics approval
Not provided at time of registration
Study design
Randomised controlled trial
Primary study design
Interventional
Secondary study design
Randomised controlled trial
Trial setting
Not specified
Trial type
Not Specified
Patient information sheet
Condition
Obsessive-compulsive disorder (OCD); Generalised anxiety disorder (GAD).
Intervention
1. Tryptophan depletion (double-blind crossover) vs tryptophan restored intervention
2. Disorder specific provocation, viz:
a. 20 min 7.5% CO2 inhalation or air (GAD)
b. Exposure to a known anxiogenic stimulus (OCD)
Intervention type
Other
Phase
Not Specified
Drug names
Primary outcome measures
Study 1: Visual Analogue Scales (VAS), The Spielberger State Anxiety Inventory (STAI), tryptophan levels, c. Profile of Mood States (POMS), Yale-Brown Obsessive Compulsive Scale (Y-BOCS)
Study 2: Visual Analogue Scales (VAS), The Spielberger State Anxiety Inventory (STAI), tryptophan levels, c. Profile of Mood States(POMS), Generalised Anxiety Disorder Inventory (GADI)
Secondary outcome measures
Beck Depression Inventory (BDI), Blood pressure/heart rate data, Swedish universities Scales of Personality (SSP).
Overall trial start date
01/07/2005
Overall trial end date
31/12/2006
Reason abandoned
Eligibility
Participant inclusion criteria
Study 1: Primary diagnosis of obsessive-compulsive disorder (OCD), currently remitted with SSRI therapy
Study 2: Primary diagnosis of generalised anxiety disorder (GAD), currently remitted with SSRI therapy
Aged 18-65
Able and willing to give informed consent prior to participation
Participant type
Patient
Age group
Adult
Gender
Both
Target number of participants
28
Participant exclusion criteria
1. No significant co-morbid anxiety disorder or other psychiatric disorder including alcohol or drug dependence
2. No major depressive episode with past 6 months
3. No significant other illness
4. No significant other medication therapy
5. No psychological therapy applied this episode
Recruitment start date
01/07/2005
Recruitment end date
31/12/2006
Locations
Countries of recruitment
Australia
Trial participating centre
School of Psychiatry and Clinical Neurosciences (M521)
Perth
6009
Australia
Sponsor information
Organisation
Raine Medical Research Foundation (Australia)
Sponsor details
Suite 24
Hollywood Specialist Centre
95 Monash Avenue
Nedlands
Perth
6009
Australia
+61 (0)8 93869880
raine@raine.uwa.edu.au
Sponsor type
Research organisation
Website
Funders
Funder type
Research organisation
Funder name
Raine Priming Grant 2005-6.
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting
Publication summary