What is the study about?
Depression (also called unipolar depression or MDD) is common mental disorder affecting about 1 in 6 people across their lifetime. Depression also occurs in bipolar disorder, a potentially lifelong condition in which people experience repeated episodes of depression and elevated mood. It affects about 1.5% of the adult population at some point in their life. Despite the prevalence of these mood disorders, the processes in the brain which bring about depression are poorly understood, and no reliable biological feature can be used to measure the presence or progress of disease or the effects of treatment.
This study has been designed to identify brain markers, which can be used in the future to help diagnose and treat patients and may be used to help in the development of new medications for unipolar and bipolar depression.
We will compare the differences in brain scans between people with bipolar depression, unipolar depression and people without depression. This will allow us to examine how brain function differs between these groups. We hope this study will help us to understand what patterns of activation in the brain are unique to these disorders.
Anhedonia (a loss of interest in activities you used to enjoy and a decreased ability to feel pleasure) is a core symptom for depressive disorders and is a focus of our research. For this research we will ask participants to lie in our MRI scanner while performing tasks requiring effort and motivation, and emotional processing. Depression also affects the stress system in the body and we will measure your stress hormones as well on a separate visit.
If you are interested in taking part in our research or just finding out more, please read on. Full details are available on the Information Sheet which we will provide when you get in touch with us.
What does participation in the study involve?
Taking part in the study involves 3 or 4 visits to our research centre at Kings College London at Denmark Hill.
Visit 1: Screening visit (3½ hours)
This visit will determine whether you are suitable for the study, through questionnaires and some standard tests for safety.
Before this visit and at the beginning of the visit you will be able to ask the team any questions about your participation. If you are okay to continue, we will ask you to sign a consent form. The rest of the visit will include an interview about your health, medical examination (blood test, urine screen, ECG and a physical exam). You will also be able to lie in our mock scanner and experience the tests of mood and motivation we will ask you to complete on the next visit. If you are suitable, you will be given some tubes to carry out a saliva collection at home over 3 days. This is to measure levels of the stress hormone cortisol. We will show you how to use these.
Visit 2: Brain scanning and computerised tests (6 hours)
Before the brain scan we need to confirm you are still suitable. This will involve asking some questions about your recent lifestyle and a urine drug screen and breath alcohol test. The MRI scan will last about 1½ hours. MRI scanning is commonly used to diagnose a number of diseases, but in this case, it will be used to take pictures of the brain while you are at rest and while you are carrying out some tasks. The scanner consists of a powerful magnet, but you will not feel any force or special sensation inside of the magnetic field.
On the same visit we will ask you to complete some questionnaires to assess your mood and other aspects of your mental/emotional functioning. You will complete some tests of your memory, attention, motivation and concentration with a researcher.
We will also take a blood sample and hair sample. The blood sample is to measure inflammation (we measure proteins in the blood that increase in number when you get an infection, are stressed, or damage any tissues in your body.) The hair sample will be used to measure cortisol levels.
Visit 3: A DEX-CRH test visit (7 hours)
Female participants will need to come in for a pregnancy test before this visit (30mins) - see below for details
The combined dexamethasone-corticotropin releasing hormone test, or DEX-CRH test, is a test which is commonly used in the diagnosis of patients with Cushing’s syndrome. This test is sensitive to detecting changes in the stress response system in depressed individuals.
For this part of the study we will ask you to take one tablet of a medication called dexamethasone at home and, on the next day, we will give you a single injection of a hormone called corticotropin releasing hormone (CRH). This is the hormone that your body produces in response to a stressful situation. We will collect some blood samples at regular intervals after you have received the CRH to measure the hormone levels in your blood. Dexamethasone is not a new drug, it is already used to treat a number of health conditions, including various skin diseases, allergies, asthma, and brain swelling.
Female participants who agree to take part in this part of the study will be asked to attend a further visit to complete a urine pregnancy test before this visit, at a time convenient for you.
Please note you can participate in the scanning part of the study without also taking part in the DEX-CRH visits. Further details can be found on the Information Sheet.
Who can take part?
The study is aimed at adults aged 18-55 who are generally in good health or have unipolar depression or bipolar disorder:
- You can take part if you are not on any medications for psychiatric diagnoses
- You can’t take part if you use recreational drugs or are dependent on alcohol or illicit substances
- You can’t take part if you have any major illnesses
- You can’t take part if you have a cardiac pacemaker or other electronic device or metal implants
- You can’t take part if you are left-handed
Will you be compensated for your time?
You will be paid £90 if you complete the first two visits to compensate you for your time. You will also have the opportunity to win up to £20 in the tasks. We will also reimburse reasonable travel expenses and provide you with a light lunch during the imaging visit. If you do not complete all the study visits, we will pay you pro rata for your time. If you decide to take part in the hormone assessment visit you will receive additional £60.
If you are interested in the study and would like more information, please email email@example.com.