Anti-inflammatory drugs could help treat symptoms of depression, study suggests

Anti-inflammatory drugs similar to those used to treat conditions such as rheumatoid arthritis and psoriasis could in future be used to treat some cases of depression, a new study led by the University of Cambridge suggests. The research further implicates the immune system in mental health disorders.

Researchers from the Department of Psychiatry led a team that analysed data from 20 clinical trials involving the use of anti-cytokine drugs to treat a range of autoimmune inflammatory diseases. By looking at additional beneficial side-effects of the treatments, the researchers were able to show that there was a significant antidepressant effect from the drugs compared to a placebo based on a meta-analysis of seven randomised controlled trials. Meta-analyses of the other types of clinical trials showed similar results.

Immune system implicated in mental health disorders

When we are exposed to an infection, for example influenza or a stomach bug, our immune system fights back to control and remove the infection. During this process, immune cells flood the blood stream with proteins known as cytokines. This process is known as systemic inflammation.

Even when we are healthy, our bodies carry trace levels of these proteins – known as ‘inflammatory markers’ – which rise exponentially in response to infection. Previous work by the same team found that children with high everyday levels of one of these markers are at greater risk of developing depression and psychosis in adulthood, suggesting a role for the immune system, particularly chronic low-grade systemic inflammation, in mental illness.

Inflammation can also occur as a result of the immune system mistaking healthy cells for infected cells and attacking the body, leading to autoimmune inflammatory diseases such as rheumatoid arthritis, psoriasis and Crohn’s disease. New types of anti-inflammatory drugs called anti-cytokine monoclonal antibodies and cytokine inhibitors have been developed recently, some of which are now routinely used for patients who respond poorly to conventional treatments. Many more are currently undergoing clinical trials to test their efficacy and safety.

The team of researchers carried out a meta-analysis of these clinical trials and found that the drugs led to an improvement in the severity of depressive symptoms independently of improvements in physical illness. In other words, regardless of whether a drug successfully treated rheumatoid arthritis, for example, it would still help improve a patient’s depressive symptoms.

 Dr Golam Khandaker, who led the study, says: “It’s becoming increasingly clear to us that inflammation plays a role in depression, at least for some individuals, and now our review suggests that it may be possible to treat these individuals using some anti-inflammatory drugs. These are not your everyday anti-inflammatory drugs such as ibuprofen, however, but a particular new class of drugs.”

“It’s too early to say whether these anti-cytokine drugs can be used in clinical practice for depression, however,” adds Professor Peter Jones, co-author of the study. “We will need clinical trials to test how effective they are in patients who do not have the chronic conditions for which the drugs have been developed, such as rheumatoid arthritis or Crohn’s disease. On top of this, some existing drugs can have potentially serious side effects, which would need to be addressed.”

Dr Khandaker and colleagues believe that anti-inflammatory drugs may offer hope for patients for whom current antidepressants are ineffective. Although the trials reviewed by the team involve physical illnesses that trigger inflammation and hence potentially contribute to depression, their previous work found a connection between depression and baseline levels of inflammation in healthy people (when someone does not have an acute infection), which can be caused by a number of factors such as genes and psychological stress.

“About a third of patients who are resistant to antidepressants show evidence of inflammation,” adds Dr Khandaker. “So, anti-inflammatory treatments could be relevant for a large number of people who suffer from depression.

“The current approach of a ‘one-size-fits-all’ medicine to treat depression is problematic. All currently available antidepressants target a particular type of neurotransmitter, but a third of patients do not respond to these drugs. We are now entering the era of ‘personalised medicine’ where we can tailor treatments to individual patients. This approach is starting to show success in treating cancers, and it’s possible that in future we would use anti-inflammatory drugs in psychiatry for certain patients with depression.”

The results of the study are published in the journal Molecular Psychiatry.

 

 

 

 

 

 

 

 

 

Has a sudden onset. Full medical glossary
Any drug that suppresses inflammation Full medical glossary
Special proteins in the blood that are produced in response to a specific antigen and play a key role in immunity and allergy. Full medical glossary
Inflammation of one or more joints of the body. Full medical glossary
Any condition caused by the body’s immune response against its own tissues. Full medical glossary
A fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. Full medical glossary
Abnormal, uncontrolled cell division resulting in a malignant tumour that may invade surrounding tissues or spread to distant parts of the body. Full medical glossary
The basic unit of all living organisms. Full medical glossary
A disease of long duration generally involving slow changes. Full medical glossary
Feelings of sadness, hopelessness and a loss of interest in life, combined with a sense of reduced emotional well-being Full medical glossary
A viral infection affecting the respiratory system. Full medical glossary
The basic unit of genetic material carried on chromosomes. Full medical glossary
The organs specialised to fight infection. Full medical glossary
Invasion by organisms that may be harmful, for example bacteria or parasites. Full medical glossary
The body’s response to injury. Full medical glossary
A viral infection affecting the respiratory system. Full medical glossary
A chemical that helps the communication between nerve cells (neurons). Full medical glossary
Compounds that form the structure of muscles and other tissues in the body, as well as comprising enzymes and hormones. Full medical glossary
A chronic skin disease causing red, scaly patches that may be intensely itchy. It is sometimes associated with arthritis (psoriatic arthritis). Full medical glossary
A severe mental disorder in which the person affected loses contact with reality. Full medical glossary
A study comparing the outcomes between one or more different treatments for a disease (or in some instances, preventive measures against that disease) and no active treatment at all (the placebo group). Study participants are allocated to the various groups on a random basis. May be abbreviated to RCT. Full medical glossary
Studies comparing the outcomes between one or more different treatments for a disease (or in some instances, preventive measures against that disease) and no active treatment at all (the placebo group). Study participants are allocated to the various groups on a random basis. May be abbreviated to RCT. Full medical glossary
A microbe, such as a type of bacteria, that is able to resist the effects of antibiotics or other drugs. Full medical glossary
A type of autoimmune arthritis featuring chronic inflammation of the small joints, especially in the hands and feet, and eventually leading to joint destruction and deformity Full medical glossary
the organ or the body where food is stored and broken down Full medical glossary
Relating to injury or concern. Full medical glossary
Affecting the whole body. Full medical glossary