Millions of Brits could be at risk of medication-induced depression from taking heartburn pills and range of other common routine medications. 

Proton pump inhibitors (PPIs), a type of medication that helps reduce stomach acid, are one of Britain's most commonly taken medications with over 74million prescriptions in England alone in 2023.

But they are just one of a host of routine medications that could cause symptoms of depression among those who take them.

This is because PPIs, two examples being omeprazole and lansoprazole, can stop the body from properly absorbing vitamin B12 — a vital nutrient found in meat, fish, dairy, eggs and  some fortified cereals that keeps the nervous system healthy.

A lack of it is a known cause of psychological problems which the NHS says can range from 'mild depression or anxiety to confusion and dementia'. 

Leaflets that come with the drugs also acknowledge the risk, urging people to contact their doctor if they start experiencing problems with their memory, confusion or depression while taking it.

One small study, published in 2017 and based on some 350 elderly people, found about a sixth of cases of depression could be attributed to PPI use.

'PPIs can block anything from 80 per cent upwards of our stomach acid production,' Deborah Grayson, pharmacist and expert in PPI medication told MailOnline. 

She added: 'This means the amount of nutrition that we can take from the food that we've eaten is reduced.

'The body needs all our nutrients to be able to generate the 'happy hormone' serotonin — and if we're not absorbing them from our food, then the body can't create the hormone.

It's this lack of serotonin that can trigger depression and low mood. 

But PPIs are not the only commonly taken drug linked to depression risk.

Some types of antibiotics, medications given to combat bacterial infections, have also been linked to low moods.

These links are specifically focused on a class of antibiotics called fluoroquinolones of which two notable drugs are levofloxacin and ciprofloxacin.

Depression risk is acknowledged for both, with the NHS specifically stating it can trigger low mood in about one in every 100 people prescribed ciprofloxacin.

Scientists have suggested the drugs could alter the community of good bacteria in the gut, which may influence the production mood-affecting hormones in the brain, theoretically increasing risk of depression.

Antibiotics kill all bacteria, both the bad pathogens they are meant to target and, as collateral damage, the good ones in our gut.

This is why some patients are recommended to take probiotics, supplements that contain samples of good bacteria, to help boost their microbiome following a course of antibiotics. 

Anti-seizure drugs are another class of medication linked to depression risk. 

Drugs like topiramate and gabapentin, sold as Topamax and Neurontin respectively, prescribed about 700,000 times a month, are known to trigger depression or mood changes in about one in 100 people who take them.

Experts suspect the drugs may be triggering depression due to how they suppress electrical activity in the brain and nerves to help treat conditions like epilepsy. 

Steroids, prescribed some 70,000 times in England per month to treat a whole range of conditions, are another routine medication linked to depression.

These drugs, also called corticosteroids, are used to dampen inflammation in asthma, allergies and arthritis. 

Experts suspect the drugs could influence how the brain chemically responds to stress and this could cause a range of psychiatric issues, including depression.

Some studies have put the risk of suffering severe psychiatric issues from steroid medications as high as one in 20, though there is thought to be considerable variation depending on dosage and in the type of mental health problem that emerges.

NHS advice states mental health problems linked to steroid tablets typically only occur when people are on the medications for longer than three weeks.

Drug related to depression can be difficult to diagnose because of the inherent complexities of the condition.

Medics must consider if a drug is causing depression or if a patient is suffering it for a separate unrelated reason to their medication, such as problems in their personal life. 

Ms Grayson urged people to not stop taking medication when they experience a side-effect like depression, but instead to speak to their GP or pharmacist.

'A GP or pharmacist can intervene in some way, change it to a different medication, or check B12 and folate levels, which are both seen in depression and find ways of compensating for what is happening,' she said. 

She added it was important people seek help with depression in all circumstances, including if it was related to their medication.

'Often patients will look at the leaflet and notice one of the side-effects is depression and assume because it's written in the leaflet, they should juts put up with it, which is obviously not the appropriate course of action,' she said. 

If you are feeling depressed and those symptoms have been consistent for more than two weeks, the NHS advises to speak to a GP about your symptoms. 

It's particularly important to do this if your symptoms are not improving, if it is affecting your work or relationships and if you have thought of suicide or self-harm.