Effects of Ghrelin Administration on Dopamine and Effort

What Was Tested

This registered phase 1, phase 2 trial tested Ghrelin.

Ghrelin is a stomach-derived hormone and the only known circulating peptide that stimulates appetite.

However, similar evidence on the putative role of ghrelin in humans is still lacking.

It had three arms (groups): Ghrelin infusion (experimental), Placebo infusion (placebo comparator) and Patients with MDD (no intervention).

Saline.

Patients with major depressive disorder will be enrolled for comparison to healthy participants on the reward task battery, but not randomized to the ghrelin vs. saline infusion.

The registry classes the interventions as drug and other.

Who Took Part

26 actual participants took part.

It was open to people of any sex aged from 20 years up to 50 years.

Healthy volunteers could join, not only people with the condition.

Examples of who could join: Healthy control participants: never fulfilled the criteria of any mood or anxiety disorder (except specific phobia). Patients with major depressive disorder: diagnosis according to DSM-5 within 12 months before enrollment and presence of at least mild symptoms at enrollment (BDI II \>= 14).

The full record lists 2 inclusion and 3 exclusion criteria; among the exclusions: lifetime history of a brain injury, schizophrenia, bipolar disorder, and a severe substance use disorder according to dsm-5; obsessive-compulsive disorder, trauma- and stressor-related disorder, somatic symptom disorder, and eating disorder within a 12-month interval before the test day; neuroimaging study involving ghrelin infusion: contraindication for pet/mr (e.g., metal implants or prostheses, pregnancy, claustrophobia).

How the Study Was Run

It was run as a randomized, crossover and triple-blind study.

Because people in this Ghrelin study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

In the crossover set-up each of the participants took both Ghrelin and the comparison in turn, acting as their own control.

Blinding on both sides kept the participants and researchers unaware of who received Ghrelin.

Those kept unaware of assignments: participant, investigator and outcomes assessor.

It started in 2022-02-21 with completion listed for 2024-08-06.

It ran at 1 site in Germany.

Its stated primary purpose is basic science.

What Was Measured

Researchers chose this as the main measure: Ghrelin-induced changes in dopamine release (time frame: During the infusion (up to 90 min)). Ghrelin-induced changes in motivation (time frame: During the infusion (60-90 min after start of the infusion)). Ghrelin-induced changes in functional connectivity and perfusion (time frame: During the infusion (up to 90 min)).

It also tracked 1 secondary outcome, for example Ghrelin-induced changes in mood.

What This Means in Plain Language

Put simply, this is a phase 1, phase 2, randomized trial of Ghrelin in 26 people.

Its size is small, so on its own it can only give an early look.

The trial is marked completed; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Ghrelin compound page, all human trials.