Pramipexole to Target "Anhedonic Depression" (PILOT-PRAXOL)

December 11, 2025 updated by: Daniel Lindqvist, Region Skane

Pramipexole Augmentation to Target Anhedonia in Depression - a Pilot Study

The heterogeneity of depression suggests that different neurocircuits and pathophysiological mechanisms are involved. Anhedonia - the inability to experience pleasure from, or the lack of motivation to carry out, usually enjoyable activities - is an endophenotype within the depression spectrum, with a distinct pathophysiology of dopaminergic mesolimbic projections. Anhedonia is common in depression and associated with treatment resistance. Pramipexole, an agonist to the dopamine -receptor 3, is an established treatment of Parkinson's disease. Based on its mechanism of action, pramipexole might be efficacious in a subtype of depression characterized by anhedonia and lack of motivation - symptoms linked to dopaminergic hypofunction. In this proof-of-concept pilot study the investigators test the anti-anhedonic and antidepressant effects of add-on pramipexole using an "enriched population study design" including only depressed patients with significant anhedonia. To understand the neurobiology of anhedonia in depression and to identify treatment predictors, the investigators also do assessments of anhedonia-related neurocircuitry using (f)MRI and blood biomarkers.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
13

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Sweden
      • Lund, Sweden, 22358
        • Psychiatry Clinic, Lund, Region Skåne

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Age ≥18 and ≤75.
  2. Diagnosis of unipolar depression; bipolar disorder in depressive phase or dysthymia.
  3. Symptoms of depression; Total-score ≥ 18, measured by Montgomery-Åsberg Depression Rating Scale (MADRS).
  4. Symptoms of anhedonia; Total-score < 27, measured by Dimensional Anhedonia Rating Scale (DARS).
  5. Ongoing treatment with at least one antidepressant drug ≥ 4 weeks without major changes in dosage. Patients with bipolar disorder must have a mood-stabilizing drug treatment.
  6. Must sign an informed consent. -

Exclusion Criteria:

  1. Ongoing pregnancy, breastfeeding or planning for pregnancy.
  2. High suicidality assessed by the researcher with medical degree.
  3. Ongoing substance use disorder (last 12 month).
  4. Diagnosis of psychosis.
  5. Ongoing involuntary psychiatric treatment.
  6. History of Impulse-control disorder or current ADHD diagnosis.
  7. Diagnosis of Intellectual disability, dementia, or other circumstances leading to difficulties to understand the implications of participating in the study and to give informed consent.
  8. Diagnosis of renal failure (eGFR < 50 ml/min/1,73 m2 ) or severe cardiovascular disease (defined as symptoms of heart failure NYHA class 2).
  9. Recently committed to psychotherapy (during the last 6 weeks) or planning for psychotherapy during the participation of the study.
  10. Ongoing ECT-treatment.
  11. Other diseases, disorders or medical treatments that according to the researchers might influence the results of the study or increases the risks of the study. Such as Parkinson's disorder, liver failure, cancer not in remission (for at least over a year).
  12. Confirmed or suspected allergy to the active substance or excipients of the drug used in this study.
  13. Committed to other trials
  14. Other reasons that according to the researcher might prevent the subject to fulfill the obligations of the study. For example insufficient drug compliance. -

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Pramipexole
Drug: Pramipexole Pill
Add-on pramipexole

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Dimensional Anhedonia Rating Scale (DARS) Score
Time Frame: baseline to week 10
Change in anhedonia symptoms (total score on the DARS). The range is 0-68, lower score indicating more severe anhedonia.
baseline to week 10

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Response
Time Frame: baseline to week 10

Montgomery Åsberg Depression Rating Scale (MADRS). The range is 0-60, lower score indicating less general depressive symptoms.

Response definition: reduction of at least 50% Remission definition: MADRS total score equal to or below 10
baseline to week 10
Montgomery Åsberg Depression Rating Scale (MADRS) Score
Time Frame: baseline to week 10
Change in depression symptoms (total score on the MADRS). The range is 0-60, lower score indicating less general depressive symptoms.
baseline to week 10
Snaith-Hamilton Anhedonia Pleasure Scale
Time Frame: baseline to week 10
Change in anhedonia symptoms (total score on the Snaith-Hamilton Anhedonia Pleasure Scale) score 0-1-2-3. Range 0-32. Higher score indicating more intense anhedonic symptoms.
baseline to week 10
Generalized Anxiety Disorder-7
Time Frame: baseline to week 10
Change in anxiety symptoms (total score on the the Generalized Anxiety Disorder-7 scale = GAD-7). Range 0-21. Higher score indicating more anxiety.
baseline to week 10
Insomnia Severity Index
Time Frame: baseline to week 10
Change in insomnia symptoms (total score on the the Insomnia Severity Index scale = ISI). Range 0-28. Higher score indicating more insomnia symptoms.
baseline to week 10
Fatigue Severity Scale
Time Frame: baseline to week 10
Change in fatigue symptoms (total score on the the Fatigue Severity scale = FSS). Range 9-63. Higher score indicating more fatigue.
baseline to week 10
The Apathy Evaluation Scale
Time Frame: baseline to week 10
Change in apathy symptoms (total score on the the The Apathy Evaluation Scale = AES). Range 0-54. Higher score indicating more severe apathy.
baseline to week 10
Change in Inflammatory Biomarkers
Time Frame: baseline to week 10
The investigators will measure blood levels of Interleukin-6 (IL-6), C-reactive protein (CRP), Tumor Necrosis Factor Alpha (TNF), and White Blood Cell count (WBC) at baseline and at study completion. The investigators will test if baseline levels and treatment-associated change in inflammatory markers can predict treatment response
baseline to week 10
Participation in fMRI With MID-task
Time Frame: baseline to week 10 (and baseline data as potential predictor)
fMRI = functional magnetic resonance tomography. Structural imaging, followed by resting-state functional imaging, diffusion tensor imaging and thereafter the MID (monetary incentive delay) task.
baseline to week 10 (and baseline data as potential predictor)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Region Skane

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Lund University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 4, 2019

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 18, 2021

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 18, 2021

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 4, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 8, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 9, 2019

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 12, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 11, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2019-001907-19

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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