False Information in UK Package Inserts for Antidepressants About a Chemical Imbalance

On 20 January 2025, I notified the UK drug regulator, the Medicines & Healthcare products Regulatory Agency (MHRA) that the package inserts for antidepressants—called patient information leaflets (PIL)—contain false statements about depression being caused by a chemical imbalance.

Two years earlier, other people raised similar questions but no changes appear to have been made. I informed the MHRA that,

“It has never been shown that people become depressed because they have low serotonin or any other ‘chemical imbalances’ in their brain. Recently, psychiatrist Joanna Moncrieff and colleagues debunked this false idea in a highly convincing umbrella review. Moreover, the statements are very harmful for the patients who might think that if they have a chemical imbalance a drug can fix, they will need to take this drug for the rest of their lives. I looked up a PIL this month for citalopram from one manufacturer, and the text was ‘These medicines help to correct certain chemical imbalances in the brain that are causing the symptoms of your illness.’ I believe it is the duty of the MHRA to check the package inserts for all antidepressants approved in the UK and to ensure that misleading messages about the cause of depression get removed in all cases.”

Two months later, the MHRA responded. One of my colleagues noted that, “This is the biggest bullshit response I have ever read.” I agree. This reply comes at the top of the bullshit pyramid I have seen during my long career. The MHRA wrote:

“It is widely recognised that depression has a multifactorial aetiology. The wording ‘chemical imbalance’ is one of several terminologies used to explain to patients, in plain English, one of the several scientific paradigms which have been adopted in the psychiatry scientific literature to attempt to provide the basis, in part, for complex psychiatric conditions such as depression.”

To state something that is blatantly false is not a “paradigm,” it is a lie, plain and simple. And depression is not “complex.” There is plenty of evidence that people become depressed because they live depressing lives. Depression is NOT a brain disorder. The diagnosis is defined as an arbitrary collection of symptoms in people who are unhappy.

“We are aware of several recent publications proposing other aetiological mechanisms which may form the basis for depression and related conditions. The totality of evolving evidence remains under close review and forms part of the ongoing benefit and risk balance assessments for the selective serotonin reuptake inhibitor medicines.”

I did not ask the MHRA to provide patients with information on all the evidence on all the different theories of depression, just not to misrepresent the evidence that exists, especially on this crucial issue.  Moreover, in science, we do not review “several” or “recent” publications if we want to become wiser. We do a systematic review of all the relevant evidence, which was what Moncrieff and her colleagues did, and overall there is zero evidence to establish that depression starts with a chemical imbalance. Is it unacceptable and hypocritical that the MHRA postulates that they closely review “the totality of evolving evidence” and then do not comment on Moncrieff’s exemplary review at all.

Next, the MHRA delivered a classic diversion. In The Art of Always Being Right, philosopher Arthur Schopenhauer describes this deplorable tactic: “If you are being worsted, you can make a diversion—that is, you can suddenly begin to talk of something else, as though it had a bearing on the matter in dispute and afforded an argument against your opponent … it is a piece of impudence if it has nothing to do with the case, and is only brought in by way of attacking your opponent.”

The MHRA wrote: “All currently licensed antidepressants have an impact on serotonin and other monoamines and their transporters and shown efficacy in treating depression within clinical trials.”

This has absolutely nothing to do with the issue of whether depression starts with a chemical imbalance. Moreover, the drugs do not have a clinically relevant effect on depression. What is obtained on the Hamilton scale is far below the minimum that can be registered as a change in the condition (see my freely available Critical Psychiatry Textbook).

The MHRA launched another diversion: “There are significant constraints within the patient information leaflets (PILs) to explain the basis for efficacy of medicinal products and it is not possible to describe all the possible mechanisms of effect for each individual antidepressant or the clinical trials data on which the positive benefit risk ratio was determined.”

To provide a lie in a patient information leaflet has absolutely nothing to do with “constraints.”

Most pathetically, the MHRA tries to get off the hook and escape their responsibility by saying that the PILs have undergone “consultation with target patient groups.” The problem with this is that patients believe what they have been told and most patients have been told the lie that depression is caused by a chemical imbalance. In 2019, Maryanne Demasi and I found that 74% of popular websites attributed depression to a chemical imbalance or claimed that drugs could correct such an imbalance.

The MHRA concludes that there are “currently no plans to remove the text referring to a chemical imbalance from the PILs.”

I wonder what it takes to make drug regulators act on false claims. The MHRA’s stance is very harmful, as it contributes to hooking the patients on depression drugs for many years, sometimes even for life. The false narrative is that drugs can fix non-existing chemical imbalances, much like insulin for diabetes. As an example, Danish psychiatry professor Poul Videbech said in 2013 that advising people to stop taking their antidepressant was like advising patients with diabetes to drop their insulin.

If something is wrong in your brain chemistry and a drug can fix that, then why would you ever stop? This is why we must insist that the MHRA changes its PILs so that the public will take less pills.