More than 200 of the most commonly prescribed drugs—ranging from heart medications, painkillers, and indigestion pills—are linked to depression and suicidal ideation (thoughts) as side effects.
This means that one in three people are unwittingly taking a prescription drug that can cause these mental health problems, say researchers from the University of Illinois.
The risk could be greater still as many older people are taking more than one of the drugs at the same time. Depression has affected around 15 per cent of people who were taking three or more of the drugs, 9 per cent of those taking two drugs, and 7 per cent of those taking just one of the drugs.
A similar pattern was seen in the rates of suicide in people taking one or more of the drugs, the researchers discovered when they analysed medication use among more than 26,000 people in the US over a nine-year period to 2014.
Even over-the-counter (OTC) medications that don't need a prescription—such as common painkillers or indigestion aids—can increase the risk of suicide and depression, the researchers warn.
The drugs don't just make the patient feel depressed—they can lead to a clinical diagnosis of depression that may trigger a prescription for antidepressants, says lead researcher Dima Qato.
Prescriptions for the 200 drugs that are linked to depression and suicide increased by 3 per cent in recent years, while use of antacids for indigestion, such as proton pump inhibitors and H2 antagonists, doubled.
Few of the drugs that can cause depression and suicide list the possible side effects, and so neither the prescribing doctor nor the patient is aware of the increased risk.
"People are increasingly using these medications, yet very few of these drugs have warning labels," said Dr Qato.