New Study Finds Long-Lasting Depression Reduces Brain Volume

A new study involving a representative sample of people with chronic depression found a direct correlation with reduced brain volume.

The study found the affected regions involved brain areas critical for attention, cognition, learning and memory, behaviour, and emotion regulation. 

The study provides critical information on the diagnosis and treatment of depression. For many patients, the course of the disease remains the primary source of burden, with most experiencing a relapse within two years. 

Before, the correlation between disease progression and changes in brain dimensions only considered one clinical variable. For example, researchers will only look at the age at which the first symptoms started or the number of depressive episodes. Due to this, the findings were inconsistent, making it harder for clinicians to follow a multivariable approach to diagnosis and treatment.  

In the US, 2020 data shows that at least 4.1 million individuals aged 12 to 17 experienced one major depressive episode. 

What is depression?

Major depressive disorder (MDD) is a mood disorder that can cause feelings of sadness, hopelessness, and irritability. However, this disorder is often misunderstood. No single test or symptom can tell you whether one has depression.

The symptoms vary with each person, and they may change over time. Some people experience most or all of them at once. Others experience just one or two symptoms over weeks or months before their condition worsens enough to require medication treatment.

MDD often develops into more severe forms, such as major depressive episode (MDE), which lasts for at least two weeks. There can also be periods during which your symptoms seem to go away entirely without treatment.

The causes of MDD are likely multifactorial and may involve genetic, biological, environmental, and psychological factors. Some people may be more prone to depression due to family history or upon experiencing a traumatic event.

However, before clinicians can say that one is suffering from MDD, the presentation must meet the disorder’s criteria. They should refer to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).

Based on the DSM-5, individuals must present five or more of the A criteria as shown in the table below: 

Image Source: National Institute of Mental Health

Notably, these symptoms must persist for two weeks straight. They shouldn’t be due to medical conditions, mood-incongruent hallucinations, or delusions.

Depression and Its Effects on the Brain Volume

Depression can affect a person’s ability to work, socialize, and enjoy life. It can make it hard for others to get out of bed in the morning and do things they used to enjoy. Meanwhile, some may find it hard to concentrate on their tasks.

Data collection

In the study, Lemke and her associates studied the health data of 681 patients from the Marburg-Muenster-Affective-Cohort Study (MACS). This pool helped them establish the correlation between disease progression and brain structure. 

During the clinical diagnostic interview, patients answered several questions to get the following data:

• Duration of hospitalizations
• Number of hospital visits
• Disease duration
• Current medication program

Participants also completed depressive symptom assessments using the Hamilton Depression Rating Scale (HDRS) and underwent brain imaging. 

Results

Given the findings, researchers established the importance of having an adequate description of depressive disorder. This should focus on two things:

• Hospitalization: number and length of hospital visits
• Illness duration: onset of first symptoms and the number and duration of depressive episodes in a lifetime. 

The study found that longer illness duration directly affects lower grey mass volume. The change in volume is apparent in the dorsolateral prefrontal cortex and left hippocampal regions. Higher hospitalization scores affected the volume of the left insula regions and the dorsolateral prefrontal cortex on both hemispheres. 

What is particularly significant about the study is its diverse representation of patient data. 

Effect of reduced brain volume

When brain volume decreases, it results in the loss of brain cells. Ultimately, this condition can lead to problems in cognition, memory, and even the ability to perform everyday tasks. This becomes problematic for people with depressive symptoms. As it is, many of those with MDD already find it hard to concentrate and carry out tasks. 

The study found that the affected brain region is primarily the prefrontal cortex. This part of the brain is mainly responsible for behaviour regulation. Individuals with long-term depression may become trapped in an unending cycle of symptoms. 

The study was published in Neurobiology and Treatment of Depression.

Early Diagnosis and Treatment of MDD 

Major depressive disorder is a common and manageable condition. However, many people with MDD do not seek treatment. Either they don’t realize they have it or think their symptoms are just part of being human. 

The blues, sad moods, fatigue, and trouble sleeping may seem normal for them. Others don’t see any reason to bother with therapy or medication when there’s no apparent physical cause for their symptoms. However, this study suggests that early diagnosis and treatment can significantly impact one’s life. 

Stakeholders should collaborate and increase awareness about MDD to encourage those with symptoms to seek immediate consultation. 

This way, they can have early access to treatment options. People with depression and their loved ones can also address.

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