The Six Subtypes of Depression, According to a New Study

Introduction:

A new study published in Nature Medicine found six subtypes of depression, each of which responds differently to treatment modalities. This is ground-breaking in that it offers a more personalized treatment plan to those struggling with depression. 

How did they find the depression subtypes? 

One theory of mental health, particular depression and anxiety, is that they are primarily conceptualized through brain circuit dysfunctions. The theory, backed by science, says you can tell a depressed person’s brain from a healthy person’s brain based on how their brain circuits operate. With modern technology like fMRIs, researchers can see our brain circuit activity and compare it to others. This is how these researchers determined the six depression biotypes.  

What are the six depression subtypes? 

This is very new research, and as groundbreaking as the study is, needs to be backed up by other studies before conclusive results can be drawn. However, this study is very promising. 

The researchers measured 8 specific brain circuits. These were:

• Default mode (D) is activated when individuals aren’t thinking of anything. 

• Salience (S) is activated to help individuals focus on the most important stimuli.

• Attention (A) is activated when stimuli needs to be paid attention to. 

• Negative mood circuit number 1 (NS) is activated by sad stimuli

• Negative mood circuit number 2 (NTS) that is activated by conscious threat stimuli

• Negative mood circuit number 3 (NTC) that is activated by unconscious threat stimuli 

• Positive mood circuit (P) is activated when positive stimuli are introduced. 

• Cognitive circuit (C) is the thinking circuit activated by thought. 

Essentially, the researchers wanted to know: What does a depressed brain look like when it’s at rest, paying attention, sad, responding to a conscious threat, responding to an unconscious threat, happy, and actively thinking? From there, they found six specific types of depressed brains. 

When naming their subtypes, they used C to denote connectivity and A to denote activity. The plus and minus signs stand for increased or decreased, respectively. The six subtypes they found haven’t been given lay-person names, but they are:

1. DC+SC+AC+ 

Increased connectivity in the default circuit, salience, and attention. Exhibited slowed emotional and attentional responses.

2. AC− 

Decreased connectivity in the attention circuit. Resulting in lapses in concentration and impulsivity.

3. NSA+PA+ 

Increased activity in the negative mood circuit activated by sad stimuli and in the positive mood circuit, indicating heightened activity in processing both sad and happy emotions. Corresponded with prominent anhedonia and negative bias.

4. CA+ 

Increased activity in the attention circuit, results in high threat-related symptoms (paranoia, anxiety, etc.), negative bias, and poorer cognitive control, as well as working memory performance.

5. NTCC-CA− 

Decreased connectivity in the circuit activated by unconscious threat stimuli and decreased activity in cognitive circuit, indicating impaired cognitive control which is also crucial for regulating emotions

6. DXSXAXNXPXCX : Undifferentiated, did not fit a subtype. 

The individual symptomology and personality of these subtypes is yet to be determined. Further research is needed to prove this theory and provide actionable steps to help people with depression. However, it is a very good first step in demystifying depression and providing more personalized treatment to individuals. 

Do different depression types respond to different therapy? 

Although not quite ready to use in the realm of talk therapy, this study did begin testing if these types responded differently to treatment. The result was a definite yes. 

For example, DC+SC+AC+, which has higher activity in problem-solving areas of the brain, responded well to talk-therapy and behavioral therapy, whereas AC− did not respond well. CA+ responded very well to venlafaxine, an antidepressant. 

Further research is needed to sort out the details in how these subtypes respond to treatment.

Why do depression subtypes matter?

Therapy is not a one-size-fits-all approach. Even with the same diagnosis—Major Depressive Disorder, for example—people will exhibit unique symptoms and, importantly, respond to different treatments. The study cites a statistic that around a third of patients diagnosed with MDD and half of the patients diagnosed with general anxiety disorder do not respond to first-line treatment. (Meaning they require a different approach than what is considered “standard”, but are still treatable.)

The study found that each subtype responds differently to different treatments. This research into the different biotypes of depression could help psychiatrists and therapists pinpoint what type of treatment will be the most effective for clients, thereby reducing the time between beginning treatment and symptom relief, saving money on less-than-effective treatment modalities, and increasing recovery rates for those with depression. 

This study could also have revolutionary effects on the efforts to treat treatment-resistant depression, which is a condition that, until recently, is resistant to nearly all types of therapy and mental health practices. Around 30% of people with depression are treatment-resistant. 

Finding a Therapy that works for you

Until further research is done on the subtypes of depression and how different therapeutic modalities may be used to treat them, it’s important to find what works for you. If talk therapy isn’t working, try behavioral therapy or medication. Exercise and lifestyle changes may be key to some people, and they may just be good coping skills for others. 

You are not broken if typical treatment doesn’t work for you. As this research shows, there is not just one way to feel depressed, and there is not just one way to treat it.