This information is for people with dementia and their carers. It tells you about antidepressants, a treatment for people with dementia who are also depressed. It's based on the best and most up-to-date research.
Do they work?
We don't know. Most studies of antidepressants in people with dementia have been short.  Researchers think that antidepressants can take quite a long time to start working. So there would need to be good long-term studies before we could say if they help with dementia.
What are they?
Antidepressants are drugs that are usually used to help with depression.
Some antidepressants that have been tried as a treatment for people with dementia are:
Studies have looked at whether antidepressants can improve mood in people with dementia and depression. But so far the evidence has found that people with dementia who take antidepressants do no better than people taking a dummy (placebo) treatment.   
A summary of the research (a systematic review) found that the antidepressants sertraline (brand name Lustral), citalopram (brand name Cipramil), fluoxetine (brand name Prozac), and clomipramine (brand name Anafril) didn't help symptoms compared with a dummy (placebo) drug.  Two smaller studies of sertraline also found that it didn't help any more than placebo.  
How do they work?
Antidepressants affect chemicals in the brain called neurotransmitters. These chemicals help messages travel from one nerve to another. Changing the balance of these chemicals in your brain may have effects on mood and the way you think.
All antidepressants have side effects. The side effects vary from one drug to another.
Common problems are a dry mouth, feeling sick, getting an upset stomach, gaining weight, losing weight, or having sexual problems.
One study in people with dementia found that people who took sertraline were about twice as likely as people who took a dummy drug (placebo) to get diahrroea, dry mouth, or dizziness. 
Medicines often have side effects for frail older people. In one study, researchers looked at how long people in nursing homes lived after being prescribed drugs that affect the nervous system, such as antipsychotics, antidepressants and benzodiazepines. They found that all these drugs raise the risk of death in these groups of people. However, we can’t be sure the deaths were caused by the drugs. It may simply be the case that people who needed these drugs were already nearer the end of their lives, compared with people who didn’t need them. Self-harm and suicide
Children, teenagers, and young adults taking antidepressants of all kinds are more likely to think about suicide or try to harm themselves.  The risk of suicidal thoughts is highest if you're under 18. There's also a risk for young adults up to the age of 24, but the risk isn't as big.
The research doesn't seem to show an increased risk of suicidal thoughts or self-harm for people over the age of 24. 
Doctors and carers are advised to keep a careful check on anyone taking antidepressants for signs of suicidal thoughts. If you're taking an antidepressant and are worried about any thoughts or feelings you have, see your doctor or go to hospital straight away.