Summary: A large brain imaging study suggests that insomnia, depression, and anxiety, often co-occurring, share overlapping brain abnormalities. Researchers found reduced cortical surface area, smaller thalamic volume, and weaker brain connectivity across all three disorders, while each also displayed unique neural patterns.
When mapped together, these differences pointed to a shared amygdala–hippocampus–medial prefrontal cortex circuit that may underlie vulnerability to all three conditions. These insights could help explain why treatments targeting one disorder sometimes improve others and may guide future therapies.
Key Facts:
- Shared Brain Changes: All three disorders show reduced cortical area, smaller thalamus, and weaker connectivity.
- Unique Patterns: Insomnia, depression, and anxiety each also have distinct neural abnormalities.
- Common Circuit: Despite differences, all appear linked through a shared brain circuit affecting vulnerability.
Source: KNAW
Insomnia, depression, and anxiety are the most common mental disorders. Treatments are often only moderately effective, with many people experiencing returning symptoms. This is why it is crucial to find new leads for treatments. Notably, these disorders overlap a lot, often occurring together.
Could there be a shared brain mechanism behind this phenomenon?
Siemon de Lange, Elleke Tissink, and Eus van Someren, together with their colleagues from the Vrije Universiteit Amsterdam, investigated brain scans of more than 40.000 participants from the UK Biobank.
Elleke Tissink: ‘In our lab, we explore the similarities and differences between insomnia, anxiety, and depression. Everyone looks at this from a different perspective: some mainly look at genetics and in this study, we look at brain scans. What aspects are shared between the disorders, and what is unique to each one?
Overlap and differences
‘We investigated many different aspects, like the structure and connectivity of the brain tissue. In all three disorders, we observe a reduced surface area of the cerebral cortex, a smaller thalamic volume, and weaker connectivity between different brain regions.’
‘In addition, some abnormalities are unique to each disorder. For example, the severity of insomnia appears to be more closely related to smaller volumes in the brain areas associated with reward.
The severity of depression, on the other hand, seems to be more strongly related to a thinner cerebral cortex in brain areas associated with language and emotion. Instead, anxiety is more severe with weaker amygdala reactivity and functional connectivity between regions where dopamine, glutamate, and histamine play a crucial role in communication.
Similar brain circuit
But what can we ultimately do with this information? Tissink continues: ‘The regions seem separate from each other, but when you map them out together, they all turn out to be part of the same circuit (amygdala–hippocampus–medial prefrontal cortex circuit).
‘So, even though they are distinct areas, they all appear to represent different pieces of vulnerability within the same puzzle.’
‘A lot of research has been done on the overlap between anxiety and depression, but insomnia is often forgotten. This is the first time that we have investigated all three disorders at the same time, on such a big scale.
‘De comorbidity is extremely high: people may experience these disorders in different stages of their lives, or experience them all at once. There is a lot of discussion about the underlying mechanisms.
‘The treatment of insomnia, for example, sometimes also improves depression – but why? By further investigating this question, we hope to find new leads for follow-up research, as well as better treatments.’
About this insomnia and mental health research news
Author: Eline Feenstra
Source: KNAW
Contact: Eline Feenstra – KNAW
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Multimodal brain imaging of insomnia, depression and anxiety symptoms indicates transdiagnostic commonalities and differences” by Elleke Tissink et al. Nature Mental Health
Abstract
Multimodal brain imaging of insomnia, depression and anxiety symptoms indicates transdiagnostic commonalities and differences
Insomnia disorder, major depressive disorder and anxiety disorders are the most common mental health conditions, often co-occurring and sharing genetic risk factors, suggesting possible common brain mechanisms.
Here we analyzed multimodal magnetic resonance imaging data from over 25,604 UK Biobank participants to identify shared versus symptom-specific brain features associated with symptom severity of these disorders.
Smaller total cortical surface area, smaller thalamic volumes and weaker functional connectivity were linked to more severe symptoms of all three disorders.
Disorder-specific symptom severity associations were also observed: smaller reward-related subcortical regions were associated with more severe insomnia symptoms; thinner cortices in language, reward and limbic regions with more severe depressive symptoms; and weaker amygdala reactivity and functional connectivity of dopamine-, glutamate- and histamine-enriched regions with more severe anxiety symptoms.
These symptom-specific associations were often in parts of the amygdala–hippocampal–medial prefrontal circuit, highlighting the interconnectedness of these disorders and suggesting new pathways for research and treatment.
