For millions of people around the globe, antidepressants are vital medications. Unfortunately, once those pharmaceuticals have done their job inside our bodies, their biochemical effects don't stop there.

Two researchers from the University of Portsmouth are calling for greater awareness of the risks posed by our prescriptions once they've been flushed into the environment, in the hope we might find ways to reduce their ecological impact.

"Our aquatic life is bathing in a soup of antidepressants," says marine biologist Alex Ford from Portsmouth's Institute of Marine Biology.

"Antidepressant and antianxiety medications are found everywhere, in sewage, surface water, ground water, drinking water, soil, and accumulating in wildlife tissues."

And there's a growing pile of evidence suggesting this 'soup' of antidepressants and their break-down products is taking its toll on marine life.

More frightening still are indications that it doesn't take a high concentration for effects to appear.

"Laboratory studies are reporting changes such as how some creatures reproduce, grow, the rate at which it matures, metabolism, immunity, feeding habits, the way it moves, its colour and its behaviour," says Ford.

Several years ago, the researcher showed how low levels of selective serotonin reuptake inhibitors such as fluoxetine – the key compound in the antidepressant Prozac – altered the behaviour of amphipod shrimp, causing them to leave sheltered spots more often and risk being preyed upon.

Working with Helena Herrera, an expert in ethical pharmacology, Ford is calling for more research into the risks and benefits of psychotropic prescriptions for the environment in addition to human health.

There's little question that mood medications help many people deal with chronic levels of clinical depression and anxiety. What is of concern is a growing number of people are turning to pharmacological treatments, increasing levels of psychotropic drugs in the environment.

A study published in 2016 found a 26 percent increase in the use of antidepressants among children and adolescents in the US from 2005 to 2012. The UK saw a 54 percent jump during the same period.

With roughly one in ten people across the Western world on long term courses of antidepressants, this upward trend has the potential to spark an environmental catastrophe.

Without adequate measures for eliminating these chemicals from our waste, we need to ask a hard question – do all of us really need to be medicated, or should we be encouraging alternatives in the name of healthier marine ecosystems?

Swapping pills for therapy or reducing their use won't work for everybody, but as part of a multipronged approach it could help keep a cap on that growing concentration of psychotropic waste.

Disposal programmes that are tasked with collecting unused medications from patients are already active in many parts of the world, yet vary in their popularity. Improved education could make a significant difference there as well.

"Could educating the medical profession help improve the utility of take back programmes and patient behaviour with regard to drug waste?" the researchers ask.

They're confident that even small steps would make a big difference.

Other contributions to a solution could include pharmacological companies themselves stepping up and taking a leading role in a 'cradle-to-grave' strategy for managing the journey beyond a medication's delivery.

UK waste management services could also upgrade their infrastructure to reduce the levels of synthetic oestrogens in waste water, they suggest.

"These substances are not currently covered by existing regulations with regards to sewage management, and analytical methods for detection are just now becoming available," the researchers write.

However we manage it, it's clear that action is needed, and it's a problem we can all do something about.

Getting a prescription to antidepressants is a big step forward for many people with a life-changing disorder. Sadly, it means our waterways and estuaries are getting a prescription as well.

This report was published in BJPsych Bulletin.