In this pharmacological study, we will examine the influence of two so-called neurotransmitters on the stress response, dopamine and noradrenaline. We will look at the specific roles of these neurotransmitters on this stress response, which might help to develop more effective treatment for patients with stress-related disorders. To this end, we will use medication to temporary block the effects of these neurotransmitters on the brain. Additionally, we will make detailed images of your brain by means of an MRI-scanner, and use a standardized stress procedure to induce stress.
What to expect?
In this study we will use different groups. In each group, participants will be treated with different medication: haloperidol, propranolol, or placebo. The dose of this medication is very low, so that the risks of participating are negligible. If you are going to participate, you will be randomly organized in one of these groups. You will get an expense allowance of €153.75 – €163.75 for taking part in the entire study, based on your performance.
How this unfolds?
This study consists of three parts. First, we will approach you for a phone call, in which we will explain all the study procedures. Also, we will then ensure your health before participation, and there is room for questions about the study. When you decide to participate, you will be asked to visit the research center twice, with 2-5 days in between. During the first visit, which will take 215 minutes, you will be asked to perform a few tasks, fill in some questionnaires, and we will make a detailed image of your brain by means of an MRI-scanner. This MRI scan will take 45 minutes. During the second visit, you will be treated with the study medication (haloperidol or propranolol) or a placebo. Also, you will be asked to perform a few tasks, you will or will not take part in a stress procedure, and perform tasks inside the MRI-scanner. This MRI scan will take about 70 minutes. Lastly, you will be asked to stay at the research center for a while, during which we will monitor you on possible side effects of the treatment. During this waiting period (~4.5h), you could do something for yourself. In total, this will take 570 minutes.
In order to participate in this study, we require participants to meet the following criteria:
- Age: between 18 and 40
- Right handed
- BMI between 18.5 and 30
- Normal vision, or corrected to normal vision
- Speaking and understanding of the English language
Participants with any of the following are excluded from the study:
- Incompatibility with the MRI scanner (due to metal in upper body, claustrophobia, epilepsy, pregnancy, breastfeeding, or active implants)
- A history of brain surgery
- Color blindness
- Any relevant current or past psychiatric or psychotic disorder, including suicidality
- First degree family member with schizophrenia, bipolar disorder, or major depressive disorder
- Neurological disorder
- Endocrine disorder
- Endocrine treatment
- Glaucoma or increased risk for glaucoma
- Melanoma or undiagnosed skin lesion
- Any other clinically significant hepatic, metabolic, obstructive respiratory, renal, cerebrovascular, cardiovascular, oncological, ocular, or pulmonary disease/disorder
- Raynaud’s syndrome
- Hypersensitivity to Haloperidol or Propranolol
- Hypertension (i.e. diastolic blood pressure > 95 mmHg at rest, or systolic blood pressure > 180 mmHg at rest)
- Hypotension (i.e. diastolic blood pressure <50 mmHg at rest, or systolic blood pressure < 95 mmHg at rest, or heart rate < 45 bpm)
- A-V block (PR interval longer than 0.20sec or irregular PR intervals)
- Abnormal QTc-interval (QTc-interval time higher than 450 for males, and 460 for females)
- Frequent autonomic failure (fainting, dizziness, blurry vision)
- Use of any prescribed medication within the one month before the start of the study (excluding contraceptives)
- Use of ‘over the counter’ medication within three days before the start of the study (excluding paracetamol)
- Dependence on alcohol or drugs
- Average alcohol consumption of 3 beverages or more daily
- Use of alcohol 24 hours before the start of test sessions
- Weekly Cannabis use for a duration of at least 3 months in the last 6 months
- Use of Cannabis within 2 weeks before the start of the study
- Weekly or more use of recreational drugs or psychotropic medication
- Use of drugs within 72 hours before the test sessions
- Habitual smoking (more than one pack in a week)
- Smoking within 24 hours before the start of the test session
- Irregular sleep/wake rhythm
- Intense daily physical exercise
- English as native language