'If anything good is to emerge from the tragedy in Cavan, it might be that more people will safely confront the disturbing behaviour of their loved ones' Picture: Colin Keegan/Collins Dublin.

Why do it? Why would any parent kill their loved ones and then kill themselves?

In many cases, a potent mix of total despair and acute anger seems to be the reason.

Sometimes there can be a triggering event and the person cracks under the pressure that has been building up for some time. A mental switch is then turned on and they, quite simply, 'go mad' - and with tragic results.

Once the terrible decision is made, then the perpetrator can go into an altered state where absolutely anything can happen to those around them.

This mental state can last some time, as the individual may take some time to execute the plan in their heads.

There is little point in ordinary people trying to fathom the intricacies of one person's extreme mental state.

Instead, it is much more beneficial to try to understand what we can do to help people who may be thinking about suicide - and we also need to learn to address serious warning signs so that we can become more aware of impending danger.

Vaguely hoping that dangerous behaviour will stop is useless. Warning signs tend to be a precursor to more significant problems - ignore them at your peril.

Talking about death or dying is a huge warning sign for suicide, excessive control and possessiveness is more indicative of murder-suicide.

Sometimes a highly controlling individual can feel that their control is slipping from their hands and they react violently in a desperate attempt to regain control of their situation.

In this scenario, perhaps a relationship is breaking down and an individual believes that they cannot abide their partner living without them.

The person might punish their partner as an act of emotional revenge and then feel compelled to murder the children so they will never have to contemplate the awfulness of the situation.

Other perpetrators can take the decision to murder their family as a result of a genuine belief that they cannot take care of their family, and so murder is the only way out. Hopelessness about the future and a feeling that the world is against them is another warning sign that should be confronted with care and sensitivity.

Many of us can pick out from our family and friends who it is that is more sensitive and more emotionally volatile; these are the people who need extra emotional support, care and attention from their family, friends, support services and doctors.

We help the sick, the disabled and the elderly, similarly we need to help the sensitive ones and the troubled ones; those who cannot manage to live a healthy life very well and who make repeated bad decisions.

Who cares if a person is 'mad' or 'bad'? What difference does it make? What really matters is that the appropriate help is obtained before something awful, something truly terrible, happens.

Lots of people think that once an individual enters the mental health services that the person will one day get 'better' but, in many ways, we are still swinging from the trees in terms of our knowledge of the brain's health.

For every theory on the causes of mental breakdown there is another that contradicts it. For every drug that works for one person, there is another person for whom it has no effect.

A psychotherapist can achieve spectacular results and success with one client, while another client can be left feeling misunderstood and helpless. It's not always that science or the support services are failing us - although they often are - sometimes the solution is so complex and multifaceted that an enormous level of time and commitment from both the patient and the doctor is necessary.

Doctors do not know whether one method or drug will work and it is only through trial and error that an individual's issues can even hope to be resolved.

Sadly, because of the pressures from society, very often the sufferer isn't willing to commit the time and energy required for their recovery and the doctor doesn't have the spare time to devote to just one client.

How can a supposed loving parent, great teacher and upstanding member of the community decide to kill his wife and children?

Murder-suicide is a very different thing to suicide - it is extremely rare and it receives lots of sensationalist media attention. Suicide isn't so rare and so if you are concerned by the behaviour of a loved one then you need to get them help.

If anything good at all is to emerge from the terrible tragedy in Co Cavan this week it might be that more people will choose to safely confront the disturbing behaviour of their loved ones.

Stella O'Malley is a psychotherapist

Irish Independent