What is involved in the study?
Participants
About 72 people will take part in this study:
- 48 who have depression and are not on antidepressants (or have stopped antidepressants)
- 24 people who have never had depression
About the study
The study involves:
- having an interview and filling in some questionnaires to get background information and to assess your mood, personality and life experiences (taking 1-2 hours depending on how much information there is).
- a brief physical examination with an ECG (heart tracing) and blood test to make sure that you are fully fit. If you consent, a blood sample for DNA analysis will also be taken because we know that small differences in peoples’ genes can affect how the brain works and how well antidepressants treat depression.
- some computer tests that will give us information about how people react and think in particular ways. This takes about an hour and can be arranged at a different time to the interview or following it depending on your preference.
Brain scan
You will then have a brain scan during which you will carry out some computer-based tasks and have a small dose of the antidepressant citalopram or a placebo (saline) given as an infusion (injection into a vein). We will put a cannula (tube) into a vein in your arm which will stay there through the experiment so that we can take blood tests and give you the drug (citalopram) though it. Blood samples will be taken before and after the scan to allow us to measure the effects of citalopram in the body and we also need to take blood samples for about 90 minutes afterwards. The scan itself takes about 1 hour and the test takes about 2½ hours altogether.
The brain scanning involves lying still in a strong magnetic field and using computers to picture the brain and how it is working during the tasks and when the antidepressant drug is given.
Please note
- The machine is noisy and you have to lie in quite a small tube so you can feel 'closed in'.
- No radiation or x-rays are involved.
- The only known danger is with certain types of metallic objects, either in your body (like a pacemaker, surgical clips, metal implants) or carried with you (like jewellery or watches). In order to check for this we will go through a confidential questionnaire before each examination that asks you about possible metal in your body and you will be asked to take leave anything metal outside the scanning room.
- Anything with a magnetic tape (credit card or audio tape) can be wiped clean by the magnetic field.
- There are no known health dangers from being scanned.
If you are taking part in the study because you are depressed you will then start treatment with citalopram and will be carefully followed up to monitor how your depression is improving and to check for side-effects using brief interviews and questionnaires.
Second brain scan for some volunteers
Eight weeks after the first brain scan we will do another scan in all the depressed people taking antidepressants and in about half of the non-depressed controls (who haven’t been taking any citalopram). On this occasion the scan will be shorter (about 45 minutes) and only involve the computer tasks (not the citalopram infusion and therefore no cannula). You will also repeat the computer tests that don’t involve a brain scan and we will do a brief interview and give you some questionnaires to check your mood.
What happens next?
For the people who have been treated for depression we will discuss with you your further needs for treatment. If your depression has got much better then we will ask your GP to carry on the antidepressant treatment according to standard best practice guidelines for treating depression. If you haven’t improved we will help arrange further treatment either through your GP or by referring you on for further care (for example to a psychologist, psychiatrist or voluntary service).
Time commitment
If you do the full study the total time involved in the interviews, computer tests and brain scans will be about 9 hours over 3-5 sessions (depending on whether you want to do parts of the study on the same or separate occasions).
If you are being treated for depression we would want to contact you each week (4 appointments for 15 to 30 minutes each time and 4 phone calls) to check you are alright and to give you your medication.
You will be compensated for your time (£80 if you take part only in the first interview, computer testing and scan, £120 if you take part in the full study) and reimbursed for any travelling expenses.
