2. The modern era: Diagnosis and classification of depression

Although theories about the underlying causes of depression changed over the centuries, there was a remarkable level of consistency in the descriptions of the core symptoms with sadness and despondency accompanied by sleep problems and physical complaints. ‘The modern era: diagnosis and classification of depression’ reviews the contributions of Emil Kraepelin and Sigmund Freud to the current thinking on depression. Love them or loathe them, both men influenced thinking on the definition and boundaries of depression and how depression is diagnosed and classified. In more recent times, there have been international efforts to standardize approaches to diagnosis through the introduction of criterion-based classifications of mental disorders.

3. Who is at risk of depression?

One advantage of the more consistent application of diagnostic criteria for identifying individuals with a depressive disorder is that it allows national and international comparisons to be undertaken. Large-scale studies make it possible to estimate the overall prevalence and distribution of depression cases by country, culture, economic and social status, and other demographic features such as age, gender, and marital status. ‘Who is at risk of depression?’ explores the epidemiology of depression (the distribution and determinants of depression-related states), gives examples of the presentation of depression across the lifespan, and discusses the association between physical disorders and depression. Lastly, it highlights some of the current thinking on prevention of suicide.

1. A very short history of melancholia

In ancient times, ‘melancholia’ rather than ‘depression’ was used to describe mood disorders characterized by despondency. ‘A very short history of melancholia’ highlights the descriptions of melancholia and theories about its causes that held sway from ancient times until about the 19th century. It begins with Hippocrates’ black bile theory in the 4th century bc. From about ad 500 there was a shift away from the notion that mental disorders had similar causes to physical ones and a revival of beliefs that mental disorders were signs of immorality, sin, and evil. From the 1500s new attitudes towards melancholia emerged. The birth of modern psychiatry in the 19th century is also described.