Approved Research

Examining grey matter volume in psoriasis and associations with depression comorbidity and peripheral inflammation: a cross-sectional study

Lay summary

Psoriasis is an incurable inflammatory skin disease affecting 2% of people. There is significant interest in the interaction between the nervous system, immune system and skin, i.e. the 'brain-skin' axis and its role in psoriasis. This is crucial, as people with psoriasis are at high risk for several mental disorders, predominantly depression, which significantly increases disability in this population. Patients may experience significant distress, including suicidal thoughts.

Recent research links depression to inflammation, as evidenced in both the blood and the brain. Psoriasis is widely recognised to cause inflammation beyond the skin; it is feasible that brain inflammation may be implicated in depression observed in those patients. Furthermore, immune-modulating treatments for psoriasis may benefit both the skin and mood.

There is evidence that inflammatory changes of the body and brain are linked to changes in brain structure. Brain volume changes are observed in several other inflammatory diseases. In psoriasis, functional imaging studies have shown changes in emotional processing in some areas of the brain. However, there are no data about whether there are also changes in the structure or volume of the brain of these patients.  

The primary aim of the study is to investigate whether there are brain (grey matter) volume changes in patients with psoriasis compared to healthy controls and whether these changes are associated with coexistent depression. We also aim to test whether brain volume and presence of depression are mirrored by levels of blood inflammatory markers. 

In order to do this, we will compare structural Magnetic Resonance Imaging (MRI) data of patients with psoriasis to healthy controls. We will also collect information about serum inflammatory markers and coexistent disease. We will use voxel-based morphometry, which is a widely used technique for the analysis of neuroanatomical images, to analyse imaging data as well as classic statistical tests for further statistical analysis.

To the best of our knowledge, brain structure and its potential association with depression and inflammation has not been investigated in patients with psoriasis. It is anticipated that the findings will inform about the neurobiological mechanisms underlying this chronic inflammatory skin disease. This will ensure appropriate and earlier treatment interventions for these complex patients, tailored to their psychiatric comorbidity. This is important to reduce illness-related distress and psychiatric mortality, improve quality of life and influence the often life-ruining disease course.