Major depressive disorder (MDD), also known as clinical depression or major depression, is widely recognised as a mood disorder that may lead to a variety of emotional and physical problems. Globally, MDD is one of the most common psychiatric disorders and is a major burden to individuals and society. However, the mechanisms underlying MDD are still unclear. Family history and other psychiatric disorders play a key role in the development of the disease. Although not widely researched, atopic dermatitis (AD) is also associated with depressive disorder, and recent evidence suggests a 60% increased risk of MDD in AD patients.

According to an April 2022 review study conducted by Long and colleagues and published in The PLOS ONE, globally, AD was significantly positively associated with increased depression risk. This was a large systematic review study that included 20 relevant cohort and case-control studies, comprising 141,910 patients with AD. AD patients had a 1.60-times higher risk of also having depression, compared to the control group. The potential mechanism for this association is unclear, but the hormonal or immunological pathways could be a possible explanation. Social isolation and anxiety from AD might increase the risk of depression as well.

MDD and AD are significant global health burdens. GlobalData epidemiologists forecast that there were 97,890,000 12-month total prevalent cases of AD in the seven major markets (7MM: US, France, Germany, Italy, Spain, UK and Japan) in 2022. This will increase to 98,430,000 diagnosed prevalent cases in the 7MM in 2029. GlobalData epidemiologists also forecast 52,620,000 12-month total prevalent cases of MDD in the 7MM in 2022. This will increase to 53,900,000 12-month total prevalent cases in the 7MM in 2029. The increase in the number of cases of MDD can be attributed to the projected increase in the population in the respective markets during the forecast period and the high prevalence of associated conditions such as AD.

AD is a chronic inflammatory skin disease characterised by itchy skin lesions and rashes. Due to its chronic and relapsing nature, AD presents a global public health concern, with a reported prevalence of approximately 20% in children and 5% in adults. MDD is one of the major contributors to the global burden of disease, with more than 350,000,000 people living with the condition worldwide. Considering the substantial economic and health burden associated with MDD, more research is needed to understand the etiological factors associated with the condition to take preventive measures. The increase in the population with AD will potentially increase the number of people living with MDD, which will have a considerable impact on the healthcare systems. Therefore, it is important to establish effective public health strategies, including further research on the association between AD and MDD.