The Relationship of Anxiety and Depression: A Review of the Literature

The nature of the relationship between anxiety and depression has been much debated. The research in the past 15 years is reviewed in the context of three conceptual models: (a) anxiety and depression differ quantitatively; (b) anxiety and depression differ qualitatively; and (c) combined anxiety and depression syndromes (anxious depressions) differ both quantitatively and qualitatively from either pure anxiety or pure depression. The major areas of research—phenomenological, treatment, course and outcome—are considered and findings in support of each position reviewed.