Condition category
Mental and Behavioural Disorders
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
Serotonin is identified as one of the causes and treatments of anxiety disorders like social anxiety disorder. A group of drugs called selective serotonin reuptake inhibitors (SSRIs) is often recommended as first treatment for this condition. However, it is not known how SSRIs work and SSRIs have rarely been studied in neuroimaging studies. The aims of this study are to examine changes in brain activation patterns, brain connectivity, brain structure and neural responses in participants taking SSRIs for social anxiety disorder.

Who can participate?
Men and women between 18-65 years old, suffering from social anxiety disorder

What does the study involve?
All participants undergo brain scanning before and after a nine week treatment period. During some of these scans, participants are exposed to emotionally relevant tasks, like viewing slides of faces with different emotional expressions, while their brain activity is being recorded with fMRI (functional magnetic resonance imaging). Other scans involve measurements of the serotonin and dopamine transporter proteins of the brain using PET (positron emission tomography). These brain scans are then repeated after drug treatment with either SSRIs or a dummy drug for social anxiety disorder (called placebo). Participants are randomly allocated to one of these two treatments. After the drug treatment period, and after brain scanning, all participants are offered additional treatment with cognitive behaviour therapy (CBT). This is a 9 week structured form of psychotherapy focusing on thoughts and behaviours that are problematic for people suffering from social anxiety disorder.

What are the possible benefits and risks of participating?
Benefits include free treatment of a potentially serious anxiety condition. Participants also receive a small sum of money (approximately 380 USD). The risks involved are minimal, with the benefits far outweighing the risks. During PET scans, participants are exposed to radioactive material, but in low doses that do not affect normal bodily functions. Pregnant or breastfeeding women will not be included. There are also safety issues regarding MRI/fMRI scans, i.e. individuals who have metallic materials within the body may not be allowed to participate. Also individuals who have heart pacemakers or have underwent surgery of the heart or head may not participate. There may be unwanted side effects such as nausea or diminished libido from the study drugs, although previous research indicates that they are generally well tolerated.

Where is the study run from?
Uppsala University (Sweden)

When is the study starting and how long is it expected to run for?
It is expected that the study will start in mid-March 2014 (recruitment, initial neuroimaging, treatment) for the 24 participants while the remaining 24 participants will be assessed and treated during the autumn of 2014. A one year follow-up (with questionnaires) will be conducted. The study is expected to be completed by December 2015.

Who is funding the study?
Funding has been provided by the Swedish Council of Health, Working Life and Welfare; the Swedish Foundation for Humanities and Social Sciences; and the Swedish Research Council.

Who is the main contact?
Prof. Tomas Furmark

Trial website

Contact information



Primary contact

Prof Tomas Furmark


Contact details

Department of Psychology
Uppsala University
Box 1225

Additional identifiers

EudraCT number

2013-002962-38 number

Protocol/serial number


Study information

Scientific title

Mechanisms of action of selective serotonin reuptake inhibitor (SSRI) pharmacotherapy for social anxiety disorder: a randomised neuroimaging trial


Study hypothesis

It is hypothesised that treatment with the selective serotonin reuptake inhibitor (SSRI) escitalopram will alleviate social anxiety accompanied by attenuated neural responsiveness to emotional challenges in limbic brain regions including the amygdala and insula cortex. The study further evaluates, with exploratory analyses, how SSRI treatment of social anxiety disorder affects:
1. Functional brain connectivity between the amygdala and prefrontal cortex
2. Brain structure, i.e. gray matter volume and white matter integrity
3. Brain monoaminergic processes, i.e. serotonin and dopamine reuptake efficiency
It is also examined how monoamine-related gene variants influence the brain parameters above.

Ethics approval

Regional Research Ethics Committee, Uppsala, ref. 2013/184

Study design

Randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet


Social anxiety disorder (social phobia)


Patients with social anxiety disorder will be randomised into one of two treatment conditions: Escitalopram 20 mg or active placebo. All other therapies will be avoided.

1. Administration of escitalopram, 1 tablet daily, is based on the accepted recommended dose 10 mg per day during the first week and 20 mg per day for the rest of the treatment period. Participants are informed that this drug has been effective in previous controlled trials.
2. Active placebo is administered with a similar capsule. Participants are informed that it is a neurokinin-1 receptor antagonist lacking the crucial anxiolytic substance, and hence that it has been ineffective in previous controlled trials.

The treatment period is 9 weeks (63 days). Participants have an extra drug supply for another 14 days because the day of the last neuroimaging assessment may vary (hence treatment could be prolonged for maximum 14 days). Participants will undergo neuroimaging assessment with fMRI (n=48) and PET (n=24) before and after the 9 week treatment period. After the initial 9 week treatment period and neuroimaging assessments, all participants are offered Internet-delivered Cognitive Behavior Therapy (ICBT) for an additional 9 week period. This ICBT treatment is optional. The ICBT program has been found efficacious in several previous trials. Follow-up assessment (questionnaires) will be conducted after one year.

Intervention type



Not Applicable

Drug names


Primary outcome measure

1. The Liebowitz Social Anxiety Scale (LSAS)
2. Spielberger state anxiety inventory (STAI-S) during anticipatory anxiety in the fMRI-setting

Primary measures will be administered at 4 times: baseline, posttreatment after nine weeks of drug treatment, after nine weeks of additional (voluntary) cognitive behaviour therapy, and at 12 month follow-up

Secondary outcome measures

1. The Clinical Global Impression – Improvement (CGI-I) scale
2. Social Interaction Anxiety Scale (SIAS)
3. Social Phobia Scale (SPS)
4. Social Phobia Screening Questionnaire (SPSQ)
5. Montgomery-Åsberg Depression Rating Scale (MADRS-S)
6. Beck Anxiety Inventory (BAI)
7. Quality of Life Inventory (QOLI)
8. Karolinska scale of personality (KSP)
9. NEO-PI-R, personality inventory
10. Spielberger trait anxiety inventory (STAI-T)

Secondary measures will be administered at 4 times: baseline, posttreatment after nine weeks of drug treatment, after nine weeks of additional (voluntary) cognitive behaviour therapy, and at 12 month follow-up

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Social anxiety disorder (social phobia), according to DSM-5, must be the main diagnosis as assessed with the structured clinical interview for DSM disorders (SCID)
2. Otherwise somatically healthy
3. Age 18-65, but not postmenopausal
4. Willingness to participate in a symptom provocation brain imaging trial

Participant type


Age group




Target number of participants

48 individuals diagnosed with social anxiety disorder

Participant exclusion criteria

1. Treatment of social anxiety within the three months preceding the study
2. Current serious or dominant psychiatric disorder other than social anxiety disorder (e.g. psychosis, major depressive disorder, bipolar disorder)
3. Suicidal ideation
4. Chronic use of prescribed medication that could influence the results (e.g. other anxiolytic or antidepressant drugs, certain hypnotics or herbs like St John’s Wort)
5. Abuse of alcohol or narcotics
6. Pregnancy or planned pregnancy during the study period
7. Menopause
8. Previous positron emission tomography (PET) examination
9. Contraindications for MRI investigation (e.g. implants or other metal objects in the body, brain and heart operations)

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Uppsala University

Sponsor information


Uppsala University (Sweden)

Sponsor details

c/o Tomas Furmark
Department of Psychology
Box 1225

Sponsor type




Funder type


Funder name

The Swedish Council of Health, Working Life and Welfare (FORTE) (Sweden)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Funder name

The Swedish Foundation for Humanities and Social Sciences (Sweden)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Funder name


Alternative name(s)

Swedish Research Council, VR

Funding Body Type

government organisation

Funding Body Subtype

National government



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

Basic results (scientific)

Publication list

2017 results in:

Publication citations

Additional files

Editorial Notes

17/10/2017: Publication reference added.