Depression is more than feeling sad or fed up for a few days, it involves persistent sadness for weeks or months. People often downplay the condition by using the term loosely or thinking that depression is not a genuine health condition. However, depression is a real illness with real and debilitating symptoms. If major depressive disorder is left untreated, the lifetime risk of suicide is 20%. Depression can be caused by faulty mood regulation in the brain, genetic vulnerability, stressful life events, medical problems and medications.
Treatments for depression can involve a combination of things, such as lifestyle changes, talking therapies and medication. Cognitive behavioural therapy (CBT) is a commonly used form of talking therapy and can be particularly effective when combined with antidepressants.
However, prescribing antidepressants can be extremely challenging. Psychiatrists and GPs often only get a short session with a patient and have to make a decision within that timeframe. Clinicians typically pick what they think will work best, however they cannot be sure. The patients and doctors must then wait 4-6 weeks before knowing whether it was the right choice or to try something different. Only around 40% of patients respond to the first drug they are given. This means that the timeframe is generally significantly increased, and for patients at risk, this is just too long.
A new study (2020) tried to find a relationship between EEGs (electroencephalograms) and antidepressant efficiency. EEG is a non-invasive technique that measures electrical activity in the brain via external electrodes. The researchers decided to tackle the issue of trial-and-error testing of antidepressants by creating an algorithm that looked at EEG data and could predict whether their 300 patients would respond to the drug sertraline (Zoloft).
Zoloft was selected for this study as it is one of the most popular SSRI (selective serotonin reuptake inhibitor) antidepressants on the market. SSRIs work by controlling the brain’s level of serotonin. Serotonin is a neurotransmitter that affects mood, sleep and learning. Zoloft is primarily prescribed for major depressive disorder, but also for PTSD, premenstrual dysphoric disorder, OCD, social anxiety disorder and panic disorder.
The algorithm was trained on one group, and then successfully predicted the outcomes of the second group! These findings, once developed further, will be extremely useful in psychiatry. Future studies will be needed to improve the accuracy of the algorithm, as well as to start exploring whether this would also work for other drugs. However, this study has enhanced our understanding of antidepressant treatments via EEG-tailored computational models and provides hope for a world with quicker and accurate antidepressant prescriptions!
Study source: Wu, W., Zhang, Y., Jiang, J. et al. An electroencephalographic signature predicts antidepressant response in major depression. Nat Biotechnol 38, 439–447 (2020).
Accessible at: https://www.nature.com/articles/s41587-019-0397-3
Featured image source: Megan Hull. How long does it take for antidepressants to work? The recovery village (2020).
Edited by Cyrus Rohani-Shukla