While the underlying causes of depression are wide and varied, this study shows that environmental variables, including chemical exposure, may contribute to depression. The environment is no stranger to population health (Hippocrates dixit) and exposure to chemicals at concentrations considered low is now known to be almost universal.

This cross-sectional study, as well as the measurement of depression, which perhaps overestimates it, has some limitations in its design, as the authors themselves recognise, but this does not in any way invalidate their conclusions: many of the most common environmental pollutants are associated with depressive symptoms. They also suggest that the effect is mediated through inflammatory processes, which opens the door to identifying possible clinical indicators.

The Ministry of Health, in collaboration with the autonomous communities, is promoting a nationwide study to determine the pollution burden of the Spanish population. Without detriment to the numerous studies carried out in Spain by different research groups, this will be the moment when the potential repercussions of these pollutants on psychiatric disorders can be analysed. However, public health is working precisely to reduce, as far as possible, exposure to environmental chemicals in order to avoid these and other harmful effects.