Over-the-counter (OTC) acid-reflux drugs may cause depression, new research suggests.
Sufferers of the mental-health condition are significantly more likely to take proton-pump inhibitors (PPIs) every day, a Taiwanese study found.
Although unclear exactly why this association occurs, the researchers believe PPIs may alter guts’ bacterial make-up.
Previous research suggests a link between the microbiome and people’s mental health.
Although generally considered safe, PPIs have previously been associated with dementia, bone fractures, pneumonia and gut infections.
As well as being available without a prescription at pharmacies, corner shops and supermarkets, doctors dole out more than five million bottles and packets of PPIs every year in England alone to treat severe heartburn.
Around three per cent of adults in the UK suffer from depression every year.
Further studies required
Results further reveal the PPIs pantoprazole and lansoprazole are particularly associated with depression.
The researchers, from Taipei Veterans General Hospital, state further studies investigating the link between such drugs and mental-health disorders are required.
They add doctors should also continue to prescribe PPIs when needed.
The researchers conducted the study by analysing 2,366 people who took PPIs and subsequently developed depression.
Some 9,464 people exposed to the acid-controlling drugs who did not suffer from the mental-health disorder were also investigated.
The findings were published in the journal Psychotherapy and Psychosomatics.
‘PPIs are a safe way to manage heartburn and indigestion’
Speaking of the findings, John Smith, chief executive of the Proprietary Association of Great Britain, which represents OTC medicines, said: ‘We welcome any new research on OTC medicines.
‘However, although the authors of this study conclude that the potential interaction between PPIs and depression may be a risk arising from the inappropriate use of PPIs, further research is needed before a clear link to depression can be properly established.
‘The researchers moreover make it clear in their conclusions that healthcare professionals should continue to use and recommend PPIs where appropriate.
‘The study also highlighted that individuals with major depression had a greater prevalence of cumulative daily dose of PPIs than those without.
‘PPIs available OTC are only intended to be used for a short-term period and are not recommended for continuous use.
He added: ‘If used in accordance with the clear on-pack instructions and the patient information leaflet inside, then PPIs available OTC are an appropriately safe way to manage the painful symptoms of heartburn and indigestion.
‘They provide relief to millions of people around the world and allow them to get on with their life.
‘We would advise people to consult a pharmacist if their symptoms don’t improve after 14 days or if they have any concerns about their medicine.’
Depression sufferers are more likely to take proton-pump inhibitors every day (stock)
PPIs are linked to stomach cancer
This comes after research released in October last year suggested indigestion pills taken by millions of Britons significantly increase the risk of stomach cancer.
Regularly taking PPIs makes people twice as likely to develop the gastric disease, a study found.
The risk soars among those who take the drugs long term; rising five-fold after a year to more than eight-fold after three years.
The scientists, from University College London and the University of Hong Kong, suspect the pills stimulate a hormone, known as gastrin, which triggers the growth of cancerous cells.
Yet, they stressed that while the risk is dramatic, few PPI-takers develop stomach cancer, making the actual threat relatively small.
Out of the 63,397 people studied, only 153 (0.24 per cent) went on to get stomach cancer.
The researchers calculated that for every 10,000 people who take PPIs, roughly eight develop stomach cancer annually, which is four more than if none were taking the pills.
They wrote: ‘We found that long-term use of PPIs increased the risk of gastric cancer development.
‘There was a clear dose-response and time-response trend of PPIs uses and gastric cancer risk.
‘Physicians should exercise caution when prescribing long-term PPIs.’