Four types of depression have been identified by researchers using brain scans, which revealed different types of activity corresponding to each type.
Dr. Conor Liston, the lead researcher on the 2016 study, said:
The four subtypes of depression that we discovered vary in terms of their clinical symptoms but, more importantly, they differ in their responses to treatment.
We can now predict with high accuracy whether or not a patient will respond to transcranial magnetic stimulation therapy, which is significant because it takes five weeks to know if this type of treatment works.
The study, published in the journal Nature Medicine, surveyed over 1,100 fMRI brain scans of people with depression, compared to controls.
They found the four types were as follows:
- Biotype 1 - characterised by anxiety, insomnia and fatigue.
- Biotype 2 - characterised by exhaustion and low energy.
- Biotype 3 - characterised by anhedonia (inability to feel pleasure), slow movements and speech.
- Biotype 4 - characterised by anxiety, insomnia and anhedonia.
Dr Liston said:
Depression is typically diagnosed based on things that we are experiencing, but as in election polling, the results you get depend a lot on the way you ask the question.
Brain scans are objective.
It is hoped that scans will be used to identify different types of depression in future, instead of self-reported symptoms.