Readers of a certain age may remember standing in line for the nit nurse, one of those classic rituals of British schooling with the risk of humiliation at its core, like the picking of teams in PE. Except that rather than being the sap neither captain wanted on his or her team, you’d be exposed as a harbourer of head lice, an altogether worse mark of shame.

Medical interventions for children are no longer quite so mortifying, but they are still part of the fabric of school life. From learning about dental hygiene to being vaccinated, the need to support children’s physical health is a given. But what about their psychological wellbeing?

Today the government announced a package of mental health measures. The creation of a “minister for suicide prevention” grabbed headlines, although as just another title for already-busy health minister Jackie Doyle–Price it looks a lot like window dressing. More concretely, support for routine mental health checks in schools was promised. The Mail Online reports that “officials envisage … most pupils will be assessed every year from the age of four” – although it points out that the testing itself, which would take the form of a questionnaire, will not be mandatory.

If you believe in “parity of esteem” for mental and physical health, a mantra the government has touted often enough but manifestly failed to achieve, there’s no argument to be had here. The mental health practitioner should be as innocuous as the nit nurse once was. But something in newspapers’ descriptions of the scope of the programme – the Sun’s “Kids as young as four” and the Mail Online’s “EVERY schoolchild” – tells a different story.

The implication is that mental health support is nice, as long as there’s not too much of it, too young – just as there’s a sense that “parity of esteem” is a lovely aspiration, but no one is seriously entertaining it being as easy to access a psychiatrist or psychotherapist as it is to get help for a broken arm.

The reasons for this scepticism are worth examining. They go to the heart of why psychological conditions are still stigmatised.

One of them is “medicalisation”. A fear that people, especially the young, will be unnecessarily drugged-up and given a diagnosis for what might in the past have been called a personality quirk, or merely stroppy teenage behaviour. That seems reasonable. But doctors generally exercise careful judgment before recommending a course of treatment (although if they are time-poor, their judgment won’t be as good, meaning that the risk of medicalisation might actually be higher without parity of esteem). And while it’s important to recognise that all medicines have side-effects, these must be weighed against the harms of doing nothing: untreated mental illness damages the brain and can be fatal.

As for overdiagnosis, there are legitimate questions about how some mental health diagnoses shade into “normal” behaviour. Again, careful, individual judgments need to be made, something that requires proper funding.

In any case, there isn’t the same kind of hand-wringing about the necessity of treating a child with, say, epilepsy. Why not? It is because mental health conditions primarily affect our thoughts and behaviour, faculties that we are taught to view as being under our conscious control. Hence the temptation to say to someone with depression: “If only you’d just stop obsessing about your problems.” Or to someone with anxiety: “Can’t you just try to think of something else?”

If someone falls prey to alcoholism, or ends up on the streets – situations in which untreated mental health problems frequently play a part – there’s often a feeling they could have avoided those fates if they’d tried just a bit harder. If they’d had a stronger will, or taken smarter decisions.

The once widespread view that mental illness comes about through weakness of character lingers on today, although few would now admit to holding it. We live in a society that sees us as almost entirely masters of our own destiny, despite the fact that science increasingly offers evidence to the contrary. And, much as they want to make the right noises, some find it hard to stomach spending vast sums of money on people they suspect might simply have made bad choices.

This cognitive dissonance makes it particularly hard for a Tory government to follow through on parity of esteem. A political philosophy that views individual effort as the solution to personal and social problems will always have a difficult time caring for people whose thoughts and behaviour become disordered through no fault of their own. On the right of the party, transformative provision for mental health from cradle to grave is likely to be regarded as mass mollycoddling.

But these attitudes certainly aren’t restricted to Conservatives. They are something we all bear responsibility for. Stigma doesn’t vanish through good intentions alone: it requires us to carefully examine our underlying assumptions. We’ve got to get better at this, because there’s still more than enough stigma to go around.

• David Shariatmadari is an editor and writer at the Guardian