Secret documents reveal that government-funded experts were warned nearly 30 years ago that tranquillisers that were later prescribed to millions of people could cause brain damage.
The Medical Research Council (MRC) agreed in 1982 that there should be large-scale studies to examine the long-term impact of benzodiazepines after research by a leading psychiatrist showed brain shrinkage in some patients similar to the effects of long-term alcohol abuse.
However, no such work was ever carried out into the effects of drugs such as Valium, Mogadon and Librium – and doctors went on prescribing them to patients for anxiety, stress, insomnia and muscle spasms.
MPs and lawyers described the documents as a scandal, and predicted they could lead the way to a class action costing millions. There are an estimated 1.5 million "involuntary addicts" in the UK, and scores display symptoms consistent with brain damage.
The MRC hosted a meeting of eminent experts and government representatives in 1981 after research by Malcolm Lader, now emeritus professor of the Institute of Psychiatry, showed brain shrinkage occurred in some benzodiazepine patients.