Reacción a "A quarter of people with depression showed circadian disturbances in an Australian study"

This is a rigorous study of scientific interest, based on a large sample of over 11,000 people with a history of depression, which combines clinical and genetic information to advance our understanding of the heterogeneity of this disorder. The results are consistent with previous evidence regarding the relationship between circadian rhythm disturbances and depression. Approximately 23 per cent of participants exhibited a profile characterised by various sleep- and circadian rhythm-related disturbances, associated with an earlier onset of the illness, greater clinical severity, genetic predispositions and a lower perceived efficacy of certain antidepressants.

However, rather than identifying a completely new subtype, the study provides further evidence for a clinical profile that had already been proposed in previous research. The main limitations are its cross-sectional design and the use of self-reported and retrospective data. The classification is based on sleep and behavioural characteristics, without direct physiological measurements of circadian rhythms, and differences in response to antidepressants are derived from subjective assessments rather than comparative clinical trials. Furthermore, the genetic associations are generally modest, and the sample exhibits characteristics that limit the generalisability of the results.

Therefore, it cannot yet be concluded that this profile constitutes a distinct biological subtype, nor that individuals exhibiting it respond better to treatments targeting the biological clock. It will be necessary to replicate the findings in independent populations and verify their ability to predict therapeutic response. Although the study opens up interesting possibilities for progress towards more personalised treatments, for the time being it does not justify changing standard clinical recommendations.