We will never know precisely what was going through Lance Hart’s mind when he shot and killed his wife and their 19-year-old daughter outside a leisure centre in Lincolnshire this week, before turning the gun on himself.

The killings happened just days after his wife, Claire, told him that their 26-year marriage was over.

Of course he would have been traumatised. But what drives a seemingly normal man to have such an extreme reaction and kill his wife and child?

We will never know precisely what was going through Lance Hart’s mind when he shot and killed his wife Claire (right)  and their 19-year-old daughter Charlotte (left) outside a leisure centre in Lincolnshire this week

This was not an isolated incident. We often read cases of men who kill their entire close family.

This kind of murder-spree — and, yes, the vast majority of such cases are carried out by men — is referred to by forensic psychiatrists as ‘family annihilation’.

Women, too, are known to kill family members, but they are far more likely to kill just their children. And research has found that such women typically are suffering severe mental illness — often triggered by childbirth.

(Admittedly, while mental health problems during or after pregnancy are common, the vast majority of women who suffer such issues will never harm their baby.)

Of course Lance Hart would have been traumatised. But what drives a seemingly normal man to have such an extreme reaction and kill his wife and child?

It is a completely different matter with some fathers, however. Indeed, there is often no evidence that men who kill their children have an identifiable mental illness.

While we might take some comfort from this, assuming that men who turn on their families are simply suffering a temporary loss of sanity, there is in fact profound reason for concern.

This is particularly the case in so-called ‘family annihilations’ — such as the case of Lance Hart — which tend to be premeditated and are typically executed with a chilling calmness.

Psychologists have long puzzled over this phenomenon.

Although research in the U.S. has shown that ‘family annihilators’ rarely have a criminal record and will often appear to be mentally stable and dedicated to their family, their psychological profile reveals deep-seated worries about their own sense of self.

This derives from fundamental principles of human nature concerning the very different roles of motherhood and fatherhood.

For mothers, there is the over-riding sense of self-denial — putting their children’s needs above their own. This explains why women have traditionally sacrificed their own interests in favour of the greater good of the family.

For fathers, though, their responsibility concentrates more on providing for the family and being seen as the head of it. This can lead to huge pressure on the man to succeed in life.

By turn, if they fail, they are dogged by feelings of frustration and inadequacy. The tipping point can come when a man is confronted by a catastrophic loss or tragedy that threatens to undermine his sense of self-worth — as may have been the case when 57-year-old Lance Hart was told his marriage was over.

F or such people, whose family is an integral part of their identity, murdering their partner and children is akin to suicide. It is seen, perversely, as a way of regaining control; of obliterating the impending crisis.

Of course, such men are often motivated by anger and a desire to punish the spouse.

But while killing their partner as an act of revenge may be understandable, for a man to kill his children (who are innocent bystanders in a marital breakdown) is a very different matter.

I believe it is often a twisted act of love, as the man crassly believes that the crisis in their lives is so great that the children would be better off dead.

And while it is, inevitably, hard to sympathise with such men, psychologists are divided as to whether they can be held truly culpable for their actions.

Those charged with murder are quite rightly sent to prison for long periods, but others are considered in need of professional help and are treated in secure psychiatric hospitals.

Regardless of whether these men are ‘bad’ or ‘mad’, what can be done to prevent such atrocities happening in the future? The truth is that while many attacks will be pre-dated by a pattern of domestic abuse, predicting with any reliability who will behave like this is notoriously difficult.

After any such incident, questions are inevitably asked about whether anything could have been done — if someone could have spotted the signs or intervened.

Tragically, in most cases, experts agree that the answer is no.

Kate Granger is 34 and a doctor, specialising in the care of older people. She’s also dying of cancer.

In August 2011, she was diagnosed with an aggressive form of sarcoma, a type of cancer affecting the supporting tissues in the body, such as muscles, nerves, fat and fibrous tissue.

Kate Granger’s #hellomynameis campaign has proved wildly popular and has won the backing of 400,000 doctors, nurses, therapists and porters across 90 NHS organisations

Despite her terminal diagnosis, she has been fundraising for her local charity, Yorkshire Cancer Centre. Her target was £50,000, but this week she was in the news because she’s managed to raise £250,000. What a wonderful thing.

But actually this is not Dr Kate’s greatest achievement. When she was told the cancer had spread, the doctor who broke the news didn’t introduce themself or even look her in the eye.

Kate vowed to make sure that no one else would ever experience this cold-hearted treatment.

So, she set up a campaign with the slogan #hellomynameis to encourage all health professionals, from consultants to porters, to say hello and introduce themselves.

Knowing someone’s name is a fundamental aspect of making a human connection. It is the start of a therapeutic relationship between the professional and patient.

It’s such a simple thing, but it makes all the difference — it changes the patient’s entire experience of being unwell.

Kate’s campaign has proved wildly popular and has won the backing of 400,000 doctors, nurses, therapists and porters across 90 NHS organisations.

She’s single handedly managed to raise the standard of care in the NHS. What an incredible achievement. Dr Kate can be proud that she will leave this world a slightly better place than she found it.

Going under the surgeon’s knife is always a gamble — a delicate balance of potential risk and benefit. But how do you ensure that the odds are in your favour?

A few years ago, it was decided that to help with this, patients would be able to see surgeons’ survival rates and choose the person who operates on them accordingly.

Of course patients have every right to know that the surgeon operating on them is proficient, but I’ve never been convinced that league tables based on survival rates were the right way to do this. And new research confirms my suspicions.

The study shows that surgeons are more wary of operating on patients who are sicker or higher risk because they fear it will affect their mortality rates and therefore their ranking on the league tables.

So the unintended consequence of trying to improve surgical outcomes is that some of the sickest patients aren’t getting the operations they desperately need.

Without incorporating operations’ different risk levels into the statistics, mortality data is not just useless, but also potentially dangerous because it can result in very misleading conclusions.

A friend told me a colleague of hers was recently the subject of an internal investigation after his mortality statistics were analysed for one particular procedure.

The procedure involved inserting a catheter — known as a picc line — into one of the main blood vessels in the body. His mortality rates for this procedure were 100 per cent. When his managers saw this, they panicked. He was clearly a danger to the public, they reasoned.

But what they had failed to appreciate was that all his patients had a terminal illness in the first place.

The fact is that data is only as good as the people who are interpreting it. We need to know the context surrounding the statistics. Mortality rates don’t give us an idea of the inherent risk associated with operating on an individual patient.

A simple league table for surgeons is far too blunt an instrument to be of real use.

My curiosity has got the better of me: this week, I downloaded Pokemon Go.

For the uninitiated, this is an ‘augmented reality’ game that users download onto their smartphones.

Pokemon Go is being played in 30 countries around the globe and there have been claims that it will help fight childhood obesity because users have to walk about

They then amble around hunting for little monsters (virtual ones, obviously) that they can see through the camera on their phone. The game is being played in 30 countries around the globe and there have been claims that it will help fight childhood obesity because users have to walk about.

Come off it! This game is never going to solve the obesity crisis.

For starters, walking isn’t that great at helping you lose weight — you need to break into a sweat if you want to burn significant calories.

Wandering around looking for monsters is just not enough.