The Medicines and Healthcare products Regulatory Agency [MHRA] is responsible for regulating medicines.
This is a recent response by this Agency in relation to antidepressants: 
For four decades, the chemical imbalance theory has permeated our cultural understanding of depression [at least in the Western world].
Nearly 1 in 4 adults in the UK are now being prescribed antidepressants.
The Royal College of Psychiatrists seems to be increasingly defensive about the ever rising level of prescribing of psychiatric drugs.
It is revealing that a regulatory Agency should anonymously sign-off a letter that specifically relates to the subject of informed consent.
Like many others, I was prescribed an antidepressant by a doctor who explained to me that it would “correct a chemical imbalance“. I was told this in “plain English”!
The MHRA has a vital role in patient safety. The sophistry of the language used in this latest MHRA response might leave one to conclude that other factors are at ‘play’?