Depressive disorder, commonly referred to as depression, is a mental health condition that affects people from all backgrounds and communities. It is characterized by persistent low mood or a clear loss of pleasure or interest in activities over an extended period. A depressive episode involves symptoms lasting most of the day, nearly every day, for at least two weeks. Individuals experiencing depression may find that their sleep is disturbed, their appetite changes, and they suffer from poor concentration or overwhelming tiredness. Feelings of hopelessness about the future and low self-worth are also common symptoms. Globally, depression tends to be more common among women than men. The condition often arises from a complex combination of social, psychological and biological factors. In 2021, depression is estimated to have affected 332 million worldwide.

In the WHO Eastern Mediterranean Region, 1 in 5 people were affected by depression and anxiety as a result of armed conflict, insecurity, and displacement in 2017. The prevalence rate for depressive disorders in the Region was estimated at 4.7% in 2023.

Depression can severely compromise a person's ability to participate fully in daily life, causing difficulties with relationships, productivity at work and performance at school. Depression is a major contributor to the overall burden of disease globally. In 2021, depressive disorders alone were identified as the second leading cause of global years lived with disability (YLDs), contributing 6.2% of all YLDs worldwide. The economic consequences of depression and anxiety are substantial; estimates suggest 12 billion productive work days are lost every year, resulting in an annual cost of approximately US$ 1 trillion in lost productivity worldwide.

People with depression are at an increased risk of suicide. For adolescents and young adults aged 15–29 years, suicide was the second leading cause of death globally in 2015. There is also a recognized strong relationship between depression and serious physical health challenges, such as cardiovascular disease, cancer, diabetes and respiratory diseases. Successfully increasing access to effective treatment for depression and anxiety offers a return of US$ 4 for every US$ 1 invested in scaling up treatment.

The World Health Organization (WHO) works with Member States and partners to address depression and strengthen mental health interventions. The Organization's commitment is guided by the Comprehensive Mental Health Action Plan 2013–2030, which outlines the steps necessary to provide appropriate care. Despite the availability of effective treatments, the global treatment gap is substantial; only 9% people with depression received minimally adequate treatment globally in 2021. This gap is particularly acute in low- and middle-income countries, where more than 75% of individuals with mental disorders receive no treatment.

WHO has developed effective psychological interventions that can be delivered by non-specialists, such as Problem Management Plus and the self-help Step-by-Step programme. For example, the digital intervention Step-by-Step was found to be effective in reducing depression among Syrian refugees in Lebanon. Following positive results in the WHO Eastern Mediterranean Region, Lebanon's National Mental Health Programme has since scaled up this intervention to be accessible nationwide. These innovative approaches are vital for closing the existing treatment gap and promoting better health outcomes for populations across the world.