A new epidemic has broken out, and it’s not CoVID-19.  The symptoms are an inability to subtract, and a tendency just to add.  It’s sweeping through physicians around the world who, instead of weaning patients off antidepressants, continue to layer on two or even more psychoactive drugs, despite evidence that this strategy is ineffective.

Depression is a global problem and is difficult to manage medically. In the past, physicians have been slow to recognise and treat depression. In one study conducted last century, one in ten patients self-diagnosed depression but fewer than half of these patients were identified by their physicians as depressed.

Pruning psychoactive drugs is essential to prevent depression re-emergence and serious side effects.

This century the pendulum has swung the other way. Modern screening techniques now err of the side of diagnosing higher rates of depression and antidepressant prescribing has increased – disturbingly in the elderly and adolescents, where adverse events can be deadly.

Depression is a chronic condition. More than one third of patients experience recurrent episodes within a year. Although antidepressants reduce relapse rates, there is no consensus on how long drug treatment should last, how antidepressants should be stopped, or when.

Given the lack of medical consensus, it is no surprise then that patients are kept on treatments for long periods of time. Long enough to see the rates of re-emergence of symptoms, or what is called “breakthrough depression”, increase.

Rather than attempting the difficult task of weaning patients off antidepressants, it is now more common to simply add more psychoactive medications. Sixty percent of adults taking antidepressants are prescribed two or more such medications. The second most common medication after an antidepressant is a sedative, followed by mood stabilizers, anti-anxiety agents, antihistamines and anticholinergics.

Physicians are competent in changing medications and adding them but very reluctant to reduce the number of medications – despite good evidence. Recent studies have shown that polytherapy (the prescribing of more than one antidepressant agents), is no better than monotherapy ((the prescribing of one antidepressant agent) and monotherapy may even be better.

Pruning psychoactive drugs is essential to prevent the re-emergence of symptoms and serious side effects, particularly in the two ends of the age spectrum. We now have “hyperpolypharmacy” to worry about. The proportion of older people taking 10 or more medicines has more than tripled. Similar high numbers of psychotrophic drugs are prescribed in adolescents in foster homes.

Two drugs have nearly 20% more side effects, which doubles when one more drug is added to make three.

Guidelines recommend staying on antidepressants for at least a year. They are often slow to change. For example, new evidence shows that the relapse rates from depression remained unchanged after six months despite the number of medications, or absence of them. As clinicians we need to review a patient’s medications at six months, prune and deeply.