Condition category
Mental and Behavioural Disorders
Date applied
15/04/2005
Date assigned
10/05/2005
Last edited
29/03/2006
Prospective/Retrospective
Prospectively registered
Overall trial status
Completed
Recruitment status
No longer recruiting

Plain English Summary

Not provided at time of registration

Trial website

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

Publication citations

Additional files

Editorial Notes