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Completed

NCT Number: NCT06576440

Effects of Ghrelin Administration on Motivation

Everyday humans are confronted with a plethora of rewards competing for their attention. Nevertheless, to obtain a goal or reward, humans often need to invest effort. When humans are confronted with the challenge to integrate costs of action such as the effort of walking to one's favorite lunch place with its anticipated benefits (i.e., eating one's favorite meal), accumulating evidence suggest that humans might "go with the gut". Ghrelin is a stomach-derived hormone and the only known circulating peptide that stimulates appetite. At the same time, patients with major depressive disorder report deficits in motivated behavior which are oftentimes accompanied by changes in appetite and weight. Based on a wealth of accruing evidence from animal studies, the investigators suggest that the gut acts as an important arbitrator in effort allocation by signaling the energy level of the body. Within this physiological framework, ghrelin is thought to signal a short-term energy deficit to increase reward responsivity and willingness to work for reward as compensatory (allostatic) means. Here, the investigators propose to conduct a follow-up study (to NCT05318924) with subcutaneous administration of ghrelin vs. saline in patients with major depressive disorder and healthy control participants. During each visit, participants will receive a subcutaneous administration of either ghrelin or saline and perform an effort allocation task where they have to exert physical effort to obtain food and monetary rewards. The investigators hypothesize that ghrelin will increase the motivation to exert effort for rewards. The goal of this follow-up study is to test that the motivational effects of ghrelin are similar in patients with depression and healthy control participants. Furthermore, participants resting energy expenditure will be estimated before and after the administration. In line with a role of ghrelin as an energy deficit signal, the investigators expect ghrelin to decrease energy expenditure. During each visit, participants will answer questions about their current mood and physiological state. The investigators hypothesize that ghrelin increases mood state and hunger while decreasing satiety.

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Key information

Conditions

Major Depressive Disorder Anhedonia Depressive Disorder Depressive Disorder, Major Mental Disorders Mood Disorders Nervous System Diseases Neurobehavioral Manifestations Neurologic Manifestations Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

20 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Department of Psychiatry & Psychotherapy, University of Tübingen

Tübingen, Baden-Wurttemberg, 72076, Germany

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Must have participated in the behavioral study arm of NCT05120336

Exclusion criteria

  • participation in the neuroimaging part of NCT05120336
  • breastfeeding
  • pregnancy

Treatment and study plan

Ghrelin

Drug

Participants in this arm will receive a subcutaneous injection of acyl-ghrelin as the active condition.

Other names: Acyl-ghrelin

Saline

Drug

Participants in this arm will receive a subcutaneous injection of saline as placebo control condition.

Other names: Placebo

Primary outcomes

  1. Ghrelin-induced changes in motivation

    Time frame: 15-50 minutes after subcutaneous administration (ghrelin vs. saline)

    Frequency of button presses on a XBox controller to obtain rewards after ghrelin administration vs. saline administration

  2. Ghrelin-induced changes in Resting Energy Expenditure

    Time frame: Pre injection versus 50-65 minutes after injection (compared to saline)

    Changes in energy expenditure after a ghrelin administration (vs. saline) as measured with indirect Calorimetry.

  3. Ghrelin-induced changes in mood

    Time frame: Pre injection timepoints (mean over 40 minutes and 5 minutes before) versus post injection timepoints (mean over 15, 50 and 65 minutes after injection) (compared to saline)

    Changes operationalized via visual analogue ratings (0-100) of the sum score of positive and negative affect schedule mood items after ghrelin administration vs. saline administration. Measures are taken ~40 minutes and 5 minutes prior to injection, as well as 15, 50, and 65 minutes after injection.

  4. Ghrelin-induced changes in hunger and satiety from baseline

    Time frame: Pre injection timepoints (mean over 40 minutes and 5 minutes before) versus post injection timepoints (mean over 15, 50 and 65 minutes after injection) (compared to saline)

    Change in visual analogue scale (0-100) measures of subjective hunger and satiety after ghrelin administration vs. saline administration. Measures are taken ~40 minutes and 5 minutes prior to injection, as well as 15, 50, and 65 minutes after injection.

Sponsors and collaborators

Lead sponsor

University Hospital Tuebingen

Other

Registry information

Official study title

The Effects of Ghrelin Administration on Motivation and Resting Energy Expenditure

Important dates

Study start
2024
Primary completion
2024
Study completion
2024
First posted
Aug 28, 2024
Registry last updated
Dec 22, 2025

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

View the official ClinicalTrials.gov record (opens in a new tab)

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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