Depression may often precede anxiety

NEW YORK, June 15 (Reuters) Contrary to the prevailing belief, it is nearly as likely that major depressive disorder will develop into a generalized anxiety disorder, as the reverse pattern, according to a study published in the June issue of the Archives of General Psychiatry. Moreover, the lifetime prevalence of both anxiety and depression has probably been underestimated.

''The close association between generalized anxiety disorder and major depressive disorder prompts questions about how to characterise this association in future diagnostic systems,'' write Dr Terrie E Moffitt, of King's College London, UK, and colleagues. Most information about having both of these conditions at the same time ''comes from patient samples and a review of patient records.

Using data from a long-term study, the researchers examined the sequential and cumulative relationship between generalised anxiety disorder and major depressive disorder. Included were 1,037 participants born between 1972 to 1973 in New Zealand, who were followed up to age 32. Diagnoses of anxiety and depression were made at seven time intervals between age 11 age 32.

The researchers report that anxiety began before or at the same time as depression in 37-per cent of depression cases.

Depression began before or concurrently in 32 per cent of anxiety cases.

Forty-eight per cent of lifetime depression cases had lifetime anxiety disorder, and 72 per cent of lifetime anxiety cases had lifetime depression.

Overall, 12 per cent of the subjects had comorbid anxiety disorder and major depressive disorder during adulthood. Of these, 66 per cent had recurrent major depressive disorder and 47 per cent had recurrent generalized anxiety disorder.

Sixty-four per cent of the cohort utilized mental health services and 47 per cent took psychiatric medications. The team reports that 8 per cent of the patients were hospitalized and 11 per cent attempted suicide.

Because of the strong relation between generalized anxiety disorder and major depressive disorder, they could be classified as a single category of distress disorders, Moffitt and colleagues suggest.

They also conclude from their findings that ''generalized anxiety disorder-major depressive disorder comorbidity may affect more of the adult population and constitute a greater health burden than previously thought.'' REUTERS AGL RK0928