More Treatment, but Not Less Anxiety and Mood Disorders: Why? Seven Hypotheses and Their Evaluation.

Mood and anxiety disorders are not only common and responsible for much functional disability [1], but epidemiological studies also indicate that their prevalence, circa 10% in Western countries, has not fallen since the 1970s despite the development of evidence-based treatments [2–8]. Prevalence refers to the percentage of adults in the general population that meet diagnostic criteria in a defined period, usually the 30 days (point prevalence) or 12 months (12-month prevalence) preceding the examination irrespective of possible earlier episodes. In sharp contrast, multiple studies have documented substantial increases in expenditures on mental health care and in treatment rates in Western countries [9–15]. The evidence on increased treatment rates comes from both general practice [16–18], nation-wide morbidity registrations [19, 20], and repeated population-based surveys [8, 21]. The treatment rate increase was bolstered by the introduction of a new class of drugs in the 1980s, the selective serotonin reuptake inhibitors, aggressively marketed by Big Pharma [22]. In addition, a number of evidence-based psychological treatments became available for people with mood and anxiety disorders. The trend data on prevalence and treatment rate reveal a remarkable paradox: more treatment but not less disorders, the treatment-prevalence paradox. The expectation to see a declining trend in the prevalence of mood and anxiety disorders with an increasing trend in treatment is not unfounded. Treatment seeks to shorten illness episodes, prevent worsening and the development of comorbidity, reduce relapses and curtail recurrences. If effective, increased treatment rates should result in lower prevalence rates in the general population, but this prevalence reduction has not occurred. The increase in the use of statins has led to significant reduction in population cholesterol levels [23]. Likewise, more and better treatment of hypertension has led to less hypertension and associated illness such as heart attacks and strokes illness [24, 25]. At least seven hypotheses can explain why more and better treatments have not reduced common mental disorder prevalence: 1. Increased willingness of individuals to report symptoms and pressures to diagnose distress as anxiety or depression has inflated prevalence rates and masked a true treatment-driven prevalence drop (further: diagnostic inflation).