There are dangers associated with horse riding. Anybody who has ever ridden will know that.
In hunting, point-to-point and eventing, often quite sizeable obstacles are jumped, opening up the possibility of a bad fall.
"It is one of the more dangerous sports, even though the safety equipment is very good," says Lucy Higginson, editor of Horse and Hound magazine.
"There have been quite a few fatalities in Britain over the years. Most people accept riding is a risk sport. The reward and the thrills more than make up for it."
In his paper earlier this year, Prof Nutt noted that riding in the UK was associated with 10 deaths and 100 traffic accidents a year. He coined the tongue-in-cheek "equine addiction syndrome" or "equasy" when suggesting it might be more harmful than ecstasy.
Dr John Silver, emeritus spinal injuries consultant, researched serious injuries in professional rugby union, gymnastics and trampolining, and horse riding, over a period of many years.
A complete statistical overview is not possible but a figure of 10 deaths a year has been cited
This is over 3-4 million riders
Many more suffer head and spinal injuries
Drug experts' warning to Johnson
He found many serious accidents resulted from a "mismatch between the skills of the participant and the task attempted".
"It wasn't necessarily that the task was too difficult for a top international rider. A lot were occurring in eventing, people were attempting cross country tasks against time and they couldn't do them against time."
Many other serious accidents happened on the roads.
"Cars, horses and riders are a lethal combination," he adds.
Higginson agreed that eventing was perhaps the most dangerous part of riding. Many television viewers will be familiar with the daunting height of some of the obstacles jumped.
"They are just very large, very heavy animals. If the horse falls over that's when it's most worrying."
But, she emphasises, accidents happen in more mundane circumstances.
Competitors now wear helmets and, often, body armour
"It can happen to people out hacking [riding at a walking pace]."
Safety equipment has become more widespread with many riders not countenancing the idea of jumping without a helmet and chest protector. There are even air bags for horse riders which are strapped to the person's body and triggered by a release cord when a rider begins to fall.
In his paper Hazards of Horse-riding as a Popular Sport, Dr Silver cited a study from 1985 that suggested motorcyclists suffered a serious accident once every 7,000 hours but a horse rider could expect a serious incident once in every 350 hours.
Dr Silver also cites a figure from 1992 of 12 equestrian-related fatalities from 2.87 million participants. He also notes that in the period from 1994-1999, 3% of all spinal cord injury patients admitted to Stoke Mandeville Hospital were the result of horse riding. The majority of people admitted to hospital in such circumstances are women.
It is not easy to gain a complete overview about the dangers of horse riding.
The British Horse Society says there are no centrally collated figures on horse riding injuries. There is no obligation to notify the society about any incident.
And of course, to fans of the sport, many of whom regard it as as much of a way of life as it is a mere hobby, any recognition of the dangers must be tempered by the positives of the sport.
WHO, WHAT, WHY?
A regular part of the BBC News Magazine, Who, What, Why? aims to answer some of the questions behind the headlines
At the time Prof Nutt's controversial paper was published, the British Horse Society pointed out the health benefits of the sport, in terms of providing good exercise and therefore prolonging life, in its attack on the comparison to ecstasy.
Mark Weston, director of Access, Safety and Welfare said: "The health benefits of horse riding are well known, how anyone can maintain that taking a class A drug has such benefits beggars belief."
After all... ecstasy isn't all that dangerous. It's dangerous insofar as, often stuff being sold as "ecstasy" is a different substance entirely.
A lot of people taking MDMA are doing so in club settings, which means that they in a particularly warm environment, shouting, and dancing. Deaths associated with it are generally related to dehydration or overheating (which makes sense given where people take it). There's also the risk that a person consuming the drug will develop a very dry mouth and will drink enough water to die of water intoxication (dissolving the sodium in their brain). I know it can cause serotonergic neurotoxicity under the right circumstances as well, but I think that's a highly unusual outcome.
But mostly, IMO it's WAY less dangerous than most illicit drugs (e.g. meth, cocaine, heroin) and a lot of legal ones too (e.g. alcohol). And unlike horses , MDMA isn't addicting.
That being said, I've never tried the stuff, and I can say with certainty I'd take a nice dangerous hack in the ring that pop a pill someone told me was MDMA.
Answer: It depends on the horse. It depends on the rider. And logic does not necessarily apply. My trainer is coming back from an accident and we were giggling about the fact that my 4 year old stallion will be the first horse she starts riding again because he is the safest one in the barn. Conversely, my worst accident was on a totally safe (behaviorally), very well broke middle aged horse who fell.
*shrug* It's all a crap shoot. I mean, a drunk driver can take you out on the way home from work. I think people need to stop being obsessed with risk and just live their lives. Take whatever safety precautions you think make sense and then realize that ultimately it is up to luck. You might make it to ten. You might make it to 100. None of us knows.