Whether or not antidepressants benefit us humans, we are not the only species exposed to them. Much of the medication we swallow is excreted, either unchanged or as chemically active metabolites. Sewage treatment plants aren’t designed to filter out antidepressants, and though levels in UK drinking water are apparently too low to affect humans, research has shown that shrimps kept in water containing a concentration of fluoxetine found in their natural habitat change their behaviour. Instead of sheltering from predators under rocks they are attracted to the light [1]. How many other species are affected by the ever-increasing range and volume of medications which are prescribed for humans, and what effects will this ultimately have on our environment and on us [2]?

Relatively little is known about this subject, which seems to merit some serious consideration. For a start, doctors should be as clear as they can be that their prescriptions are at the very least benefitting those for whom they are prescribed.

1. Guler Y, Ford A. Anti-depressants make amphipods see the light. Aquatic Toxicology 2010; 99 (3):397-404.

2. Harvey J. Prescribing for Shrimps. 11 August 2012 http://nasgp.wordpress.com/2012/08/11/prescribing-for-shrimps/#more-1213

Competing interests: None declared