What is the study about?
Bipolar disorder is a potentially lifelong and disabling condition in which people experience repeated episodes of depression and elevated mood. It is estimated that 1% of the adult population at some point in their life will experience bipolar I disorder (mania and depression), and 0.4% will experience bipolar II disorder (hypomania and depression). Despite this, the processes in the brain which bring about depression are very poorly understood, and no reliable biomarkers exist. A biomarker is a biological feature that can be used to measure the presence or progress of disease or the effects of treatment.
This study has been designed to try and identify brain scanning biomarkers 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.
We will compare the differences in brain scans between people with bipolar depression (both bipolar I and II disorder), people with Major Depressive Disorder (MDD) 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 bipolar depression.
Anhedonia (a loss of interest in activities you used to enjoy and a decreased ability to feel pleasure) is a core symptom for both MDD and bipolar depression and so the study will include tasks and assessments that assess the different components of anhedonia.
We will also look at the emotion processing areas in the brain which are known to be associated with mood disorders, so we will ask people taking part in the study to perform thinking and mood tasks whilst being scanned in an MRI scanner.
What does participation in the study involve?
Taking part in the study involves two visits to the Centre for Neuroimaging Sciences, Kings College London at Denmark Hill:
Visit 1: A screening visit which will last approximately 3.5 hours to assess whether you are suitable for the study.
At this visit you will be asked to sign a consent form and we will ask you some questions about your past and current medical and mental health. We will carry out a urine drug test and breath alcohol test and, if you are a woman who is able to get pregnant, a urine pregnancy test. We will ask you to complete some questionnaires about your mood, memory performance and personality. If you are suitable, we will also show you the tasks that you will be asked to complete at your next visit and you will be given some saliva collection tubes to carry out a saliva collection to measure cortisol levels when you wake on the morning of you next visit - the procedure for doing this will be explained at your screening visit. Cortisol is a steroid hormone made by your adrenal glands. It helps your body respond to stress, regulate blood sugar, and fight infections.
Visit 2: An imaging visit which will last approximately 5 hours.
At this visit we will carry out urine drug screens and breath alcohol tests and take a blood sample to measure inflammatory markers - these are proteins in the blood that increase in number when you get an infection, are stressed or damage any tissues in your body. We will ask you to complete some questionnaires which assess your mood and other aspects of your mental/emotional functioning. You will complete some detailed tests of your memory, attention and concentration with a researcher, and will complete some computer-based motivation tasks. You will have an MRI scan which will last about 1.5 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 whilst at rest and whilst carrying out some tasks. In order for us to take pictures of your brain, you will have to lie as still as possible whilst you are in the MRI scanner. The scanner consists of a powerful magnet, but you will not feel any force or special sensation inside of the magnetic field because your body is insensitive to it.
What could make you ineligible for the study?
The following reasons are likely to mean you can’t take part in the study:
- If you have, or have had, any serious medical or neurological conditions, or severe head injury.
- If you have a history of major psychiatric disorder (with the exception of bipolar disorder and major depressive disorder for participants with those conditions).
- If you have taken part in a research study involving administration of an experimental drug within the last month or plan to do so in the next month.
- If you are currently regularly using recreational drugs such as cannabis or cocaine.
- If you have recently had a flu vaccination.
- For women: if you are trying to get pregnant, or if you are currently pregnant or breast feeding.
- If you have a history of claustrophobia or are unable to lie still in a MRI scanner for a period of around 1.5 hours.
- If you weigh more than 126kg (19 stone 12 pounds).
- Because of the powerful magnetic field in the MRI scanner, you must not have a scan if you;
- have had any metal injuries to your eyes;
- have had metallic objects (including clips) inserted into your body during an operation;
- have a tattoo on your head/neck;
- have received a gun-shot injury; or
- have a heart pace maker.
The radiographer will go through a list of possible risks with you before you go into the scanner
- For people with bipolar and major depressive disorder: if there is likely to be a change in dose or type of your regularly prescribed mental health medications the month before the screening visit or a likely change during your participation in the study.
- For people without bipolar or major depressive disorder: if you have a family history of severe mental illness such as psychosis, bipolar disorder or schizophrenia.
Will you be compensated for your time?
You will be paid £80 if you complete both 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 imaging sessions. If you do not complete all the study visits, we will pay you pro rata for your time.