The blurred line between anxiety and depression: hesitations on comorbidity, thresholds and hierarchy

The delineation of anxiety and depression as well as the relation between anxiety and depression are still subject of debate. Many patients suffering from depression also suffer from anxiety, and many patients with anxiety suffer or will suffer from depression. The co-occurrence or co-morbidity is higher than what could be expected based on their respective prevalences, and even pushed some authors to call it cothymia. This epidemiological and clinical reality results in many conceptual hesitations. We first will summarize how the different (versions of the) classification systems do not seem to have been successful in their attempts to delineate the blurred line between depression and anxiety, before questioning whether a dialogue with a more phenomenological or psychopathological approach could be helpful in understanding the articulation between both affective phenomena, as well as in bridging neurobiological research and clinical practice.