[More treatment but no less depression. An uncomfortable paradox].

Background: Treatments for depression have improved, and their availability has markedly increased since the 1980s. Mysteriously, the prevalence of depression in the general population has not decreased. This ‘treatment-prevalence paradox’ (TPP) raises fundamental questions about the diagnosis and treatment of depression.

Aim: To clarify the TPP.

Method: We discuss seven explanations for the TPP, based on an integrative narrative review.

Results: The first two explanations assume that improved and more widely available treatments did reduce the prevalence, but that the reduction has been offset by an increase in: 1. misdiagnosing distress as depression, yielding more ‘false positive’ diagnoses; or 2. an actual increase in the incidence of first episodes. The remaining five explanations assume prevalence did not decrease, but suggest that 3. acute phase treatments and 4. relapse prevention are less efficacious than believed; 5. trial efficacy doesn’t generalize to real-world settings; 6. expansion of treatment was not optimally targeted at recurrent-chronic cases which account for most prevalence; and 7. treatments have sometimes counterproductive effects.

Conclusion: Our analysis suggest that there is little evidence that false positives or first incidence have increased as a result of error or fact but rather strong evidence that (a) the published literature overestimates treatment efficacy, that (b) treatments are considerably less effective as deployed in ‘real world’ settings, and (c) that treatment impact differs substantially for chronic-recurrent cases relative to non-recurrent cases. Collectively, these three explanations probably account for most of the paradox. Further exploration of counterproductive effects of treatment is critical. Significant prevalence reduction requires not only better treatment but foremost long-term structurally funded prevention targeting powerful determinants.