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Depression Treatment Changes Brain Structure, Scientists Say

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Strengthening decades of neural connections can make the adult brain stubbornly resistant to rapid change. If the structure of our brain traps us in dark moods and thought cycles, Recovery from chronic depression can be extremely difficult.

Some patients with major depressive disorder (MDD) can ‘rewire’ their brains within weeks when given the right treatment, according to new research.

Anti-depressants, behavioral therapy, and electroconvulsive therapy don’t work for everyone with MDD, but scientists in Germany claim these treatments have the power to change brain structures. How long these changes will last remains to be determined.

People with MDD often have trouble regulating negative emotions and their physiological responses to stress. Under such harsh conditions, it may seem burdensome to enjoy even the most enjoyable activities in life.

In the past, neuroimaging studies have found that severe depression is associated with changes in gray matter (composed of neuron bodies) and white matter (composed of nerve fibers) volumes. It is also associated with increases in amygdala activity, which affects emotional experiences; shrinkage of the hippocampus, which plays an important role in long-term learning and memory; and shrinkage in the basal ganglia that help process emotions.

Treatment-resistant MDD is manifested by changes in the basal ganglia and the lobe that processes sensory information.

If there is a really strong link between the structure of the human brain and the function of depression, it could seriously help improve diagnosis and treatment.

Today, however, researchers disagree on whether this link is consistent or robust enough to be trusted.

Researchers in Germany think so.

Their new work was presented at the 35th annual European College of Neuropsychopharmacology in Vienna. The findings show that some structural brain features found in MDD patients are alleviated when antidepressant treatment is successful.

Before receiving treatment for depression, the brains of 109 patients with MDD were scanned using a magnetic resonance imaging (MRI) machine. Patients were then administered electroconvulsive therapy, psychological therapy, or anti-depressant medications, or a combination of all therapies.

Six weeks after the initial MRI scan, the patients’ brains were scanned again. The ‘before and after’ results were then compared to the brains of 55 healthy participants.

As a result, the authors found that patients with the greatest symptom improvement also showed the most structural brain changes. After six weeks, connectivity between neurons in certain parts of their brains increased, and these effects were independent of treatment choice.

“We were surprised at the speed of response,” says psychiatrist Jonathan Repple of the University of Frankfurt.

“We have no explanation for how these changes occur or why they must occur with such different forms of treatment”.

Randomized controlled trials have shown that electroconvulsive therapy, cognitive behavioral therapy, and antidepressants can all significantly improve depressive symptoms, but it is much more difficult to attribute this improvement to structural changes in the brain.

ECT appears to be the most effective and quickest treatment of the bunch, although it has more side effects and scientists are still trying to find the most successful regimen.

ECT works by passing an electrical current through a patient’s brain while under general anesthesia, and in mouse studies, the therapy seems to improve communication between neurons in certain parts of the brain. In fact, researchers from Johns Hopkins University recently found new brain cells developing in the hippocampus of mice treated with ECT.

Studies in humans have found similar results. For example, in 2015 it was found that ECT ‘molded’ the brain structures of some MDD patients, reshaping the neural connections in their amygdala and hippocampus.

Meanwhile, antidepressant drugs are associated with neural plasticity in the hippocampus and prefrontal cortex, and CBT is associated with altered brain activation in the prefrontal cortex and precuneus associated with mental imagery and memory.

Although evidence-based, these depression treatments are not always equally effective and do not result in consistent levels of structural brain changes.

The brain is an incredibly complex structure, and human emotions are quite complex. Putting the two together is an incredibly challenging task, but that hasn’t stopped scientists like Repple from trying.

Psychiatrist Eric Ruhe, who was not involved in the current study, praises Repple and colleagues for the difficulty of their latest paper.

He says the study still needs to be replicated in independent samples, but the results “are very much in line with our current belief that the brain has much greater flexibility in adaptation (even short) than previously thought.

“This means that the brain structure of patients with severe clinical depression is not as stable as we thought, and we can recover their brain structure in as little as 6 weeks,” Ruhe explains.

“This gives hope to patients who believe that nothing can change and who have to live forever with a disease ‘etched in stone’ in their brains.”

The study was presented at the 35th annual European College of Neuropsychopharmacology in Vienna.