ClinicSpeak: limbic system and depression

Are you depressed? There is a biological reason for MSers to be depressed. #ClinicSpeak #MSResearch #MSBlog

"The lifetime prevalence of major depression in MS is ~50%; 1 in 2 MSers get depressed. This is way  and above what one expect in relation to the level of physical disability that MS causes. We know this because when we compare MSers to say people with rheumatoid arthritis with the same level of physical disability the incidence and life-time prevalence of depression is about twice as high in MSers. Why? It is almost certainly due to the fact that MS is a brain disease and affects neuronal circuits linked to mood. The study below using functional MRI shows that depression in MSers is associated with altered regional brain activity and connectivity patterns within the primitive brain system called the limbic system. What this is telling us that there is a biological/anatomical substrate to explain why MSers get depressed. I suspect this is related to damage that occurs as a result of MS inflammatory activity in the brain. In other words if we treat MS early and prevent this damage we should reduce the burden of depression in this disease."

"How do you know you are depressed? If you need help identifying whether or not you are depressed you can download this short questionnaire and complete it. If you find you are depressed can you please bring it to the attention of your family doctor, neurologist or MS nurse specialist. We have a lot of treatments for depression including lifestyle changes (exercise), counselling and behavioural therapies (CBT, mindfulness, etc.) and pharmacological interventions (antidepressants) that help MSers manage their depression."

Beck depression Inventory from Gavin Giovannoni
Riccelli et al. Individual differences in depression are associated with abnormal function of the limbic system inmultiple sclerosis patients. Mult Scler. 2015 Oct 9. pii: 1352458515606987.

BACKGROUND: Depression is common in patients with multiple sclerosis (MS), although the brain mechanisms of this psychiatric condition in MS are poorly understood. Specifically, it remains to be determined whether depression in MS is related to altered activity and functional connectivity patterns within limbic circuits.

METHODS: Seventy-seven MS patients with variable levels of depression (as assessed via the Beck Depression Inventory) underwent functional magnetic resonance imaging while performing an emotional processing task. To conduct the functional connectivity analyses, the bilateral amygdala and hippocampus, two areas critically involved in the pathophysiology of depression, were chosen as 'seed' regions. Multiple regression models were used to assess how depression in MS patients was correlated with the activity and functional connectivity patterns within the limbic system.

RESULTS: Depression scores in MS patients were negatively correlated: (1) with the activity in the subgenual cingulate cortex; (2) with the functional connectivity between the hippocampus and orbitofrontal cortex as well as the dorsolateral prefrontal cortex, and (3) with the functional connectivity between the amygdala and dorsolateral prefrontal cortex.

CONCLUSIONS: Our study showed that individual differences in depression in MS patients were significantly associated with altered regional activity and functional connectivity patterns within the limbic system.

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