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Completed

NCT Number: NCT06212284

Serotonin, Anxiety and Visceral Sensation

The goal of this crossover study was to learn about the potential regulatory role of serotonin in interoceptive processing and its relationship to levels of state anxiety. This experiment directly compared the impact of a selective serotonin reuptake inhibitor (SSRI) (20mg CITALOPRAM) to that of a PLACEBO on the neural processing of ordinary interoceptive sensations and the relationship of these influences to anxious states.

Healthy young volunteers completed the visceral interoceptive attention task with each treatment condition (citalopram and placebo). The task involves focusing attention on heart, stomach, or visual sensation control while scanned with functional magnetic resonance imaging (fMRI). The difference in haemodynamic response between interoceptive sensation(s) and visual sensation (i.e. the relative interoceptive response) is compared between treatment conditions. State anxiety is measured at each test period. It is used to test for a moderating effect of state anxiety on the influence of serotonin in interoceptive processing and used post-hoc to explore associations between changes in state anxiety and changes of interoceptive relative interoceptive response due to the SSRI.

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Key information

Conditions

Healthy Anxiety Disorders Mental Disorders

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

School of Psychology

Falmer, East Sussex, BN1 9QH, United Kingdom

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • healthy volunteer

Exclusion criteria

included:

  • the presence of significant ongoing medical condition;
  • pregnancy or breastfeeding;
  • currently taking any medication (excluding contraceptive pill);
  • first-degree family history of bipolar disorder;
  • an indication of current or historical mental health disorder,
  • MRI scanner contraindications (e.g. metallic implants)
  • data that is unanalyzable due to movement
  • excessive side effects of the drug (e.g. nausea)

Treatment and study plan

Citalopram 20mg

Drug

Doses were delivered in gelatine capsules filled with microcrystalline cellulose.

Placebo

Drug

Doses were gelatine capsules filled with microcrystalline cellulose

Primary outcomes

  1. relative neural interoceptive response - heart

    Time frame: 15 minutes

    Neural response, inferred via functional magnetic resonance imaging from focusing attention on the heart, minus the response during focus on a visual stimulus

  2. relative neural interoceptive response - stomach

    Time frame: 15 minutes

    Neural response, inferred via functional magnetic resonance imaging from focusing attention on the stomach, minus the response during focus on a visual stimulus

  3. State Anxiety

    Time frame: 5 minutes

    State Trait Anxiety Inventory

Secondary outcomes

  1. Metacognitive Interoceptive Insight

    Time frame: 45 minutes

    Ability of confidence to predict accuracy when making decisions about whether heartbeat is in sync with an auditory tone. This is an exploratory measure.

  2. Physiological and Psychological state

    Time frame: Measured twice, for 2 minutes, before and after scanning. Average taken to estimate state inside scanner.

    Three scales (from 0-100) were given to assess three somatic side effects (nausea, headache and dizziness). Five anxiety-related effects (pairs of antonyms: alert-drowsy, stimulated-sedated, restless-peaceful, irritable-good-humoured, anxious-calm) were used to confirm other anxiety measures and alert the researchers to excessive side effects. Used to confirm anxiety measure detect side effects.

  3. Positive and Negative Affect Scale

    Time frame: Measured twice, for 2 minutes, before and after scanning. Average taken to estimate state inside scanner.

    Measures affective state, confirming anxiety measure

  4. Heartrate

    Time frame: Before scans of each session, 2 minutes

    Participants had their heartrate recorded with the participant relaxed and sitting.

  5. Cerebral Blood Flow Change

    Time frame: 2 minutes, at scan

    Perfusion imaging, to control for effects of citalopram on blood flow

  6. Anatomical scan and fieldmaps

    Time frame: 6 minutes, at scan

    For coregistration of functional magnetic resonance images

Sponsors and collaborators

Lead sponsor

University of Sussex

Other

Registry information

Official study title

General and Anxiety-Linked Influence of Acute Serotonin Reuptake Inhibition on Neural Responses Associated With Attended Visceral Sensation

Important dates

Study start
2018
Primary completion
2018
Study completion
2018
First posted
Jan 18, 2024
Registry last updated
Jan 25, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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