Spare a Thanksgiving Day thought for the starvation that made us mad, literally. Maternal malnourishment red-lined rates of insanity in Ireland and, I believe, may be responsible for the schizophrenia that struck my two sisters 130 years later.

Sounds far-fetched? Now comes a book that steamrolls all doubt about what happened on my mother’s side, arguing that the mental illness that was encouraged by the Great Irish Famine churned epigenetically through the generations for the next 150 years.

My sisters–whose onset of schizophrenia was triggered 130 years later, in the mid-1970s, five generations after my ancestors arrived in Boston in 1847, having fled what’s known to history as the Irish holocaust, the Great Hunger, An Gortar Mor–may be suffering from the epigenetic results of in-vitro starvation from those earlier, famine-ravaged generations.

This was the takeaway of my memoirish 2008 book Stalking Irish Madness, so the rigorous academic work of Oonagh Walsh, who spoke last week in County Sligo, Ireland, about the release of her new book, Insanity, Power and Politics in Nineteenth Century Ireland: The Connaught District Lunatic Asylum, is a welcome reminder that famine packs a hidden mental illness sucker punch–and that yesterday’s masses are the makers of our genetic identities today.

‘You’ll Drive Yer Mudder to Ballinsaloe’

I visited the asylum that is the topic of Walsh’s book. Known more casually as Ballinasloe, for where it sits, on the outskirts of a medium-sized town of colorfully painted shop fronts right across the Roscommon County line, the place remains a stubborn byword for stressed-out Irish mothers: “You’ll drive yer mudder to Ballinasloe,” is still heard, as ever, by Irish kids today.

History wasn’t that long ago in Ireland. I reached it by following a back-country route along the Suck River, through the Suck Valley Way, and to me that was the perfect location for a bedlam for what was known as Ireland’s peasant province, surrounded by five acres of marshy ground. Between the Suck River and the bog, escape was well-nigh impossible.

The history here is not pretty. While British lords and ladies feasted on venison, and exported Irish grain, nothing less than an organic holocaust was imposed on the Irish going mad in record numbers. What’s mind-bending is the notion that my family may still be feeling the medical trauma today.

While it’s no secret that the Great Irish Famine left its mark on the tiny island nation–a million died and a million emigrated–less well known is the hard data on what happens to subsequent generations of famine victims. Downstream generations are swept away in much greater numbers, with rates of psychosis more than doubling.

Famine Boosts Future Mental Illness

Walsh said at a Science Week event in Ireland’s County Sligo last week that severe malnutrition between 1845 and 1850 caused “epigenetic change” that surely boosted rates of mental illness in successive generations.

Epigenetics, which literally means “around the gene,” is the fascinating study of changes in gene expression: it gives us a glimpse of how “nurture” gets written into the “nature” of our DNA code.

While others have speculated about long spells of starvation having caused big population bulges of madness among the Irish on both sides of the Atlantic, we’ve had to view our history through the more modern epidemiological studies of famine in Holland and China.

Their data reveal a doubling of rates of schizophrenia in offspring of mothers carrying children through famine, particularly during the second trimester of pregnancy.

So it turns out that famine data from a famine around Rotterdam in the 1940s and in Great Leap China in the 1960s inform colorful anecdotal evidence in Ireland about an outbreak of insanity among the undernourished Irish.

Famine is the epigenetic smoking gun here, folks. My own Irish-American family took only six heritable cycles of genes—six generations—for the schizophrenia to pool in our immediate family, streaming down from County Roscommon on mom’s side, the county hit hardest by famine. It’s no coincidence that the National Famine Museum is found in the bogs of Roscommon.

If anything, Walsh errs on the side of caution in making her famine-insanity claims. The smoking gun for her is the increase of patients in asylums after the Great Irish Famine. Yet we know that, by the 1830s, so many poor people were suffering from bipolar disorder and schizophrenia—lunacy in the parlance of the day—that a report that year on the pauper insane noted the many complaints about “wandering lunatics” who had been “dispersed over the country in the most tragic and disgusting state.”

A Century of Mini Famines Before Big One

A series of famines (in 1740, 1755, 1766, 1783, 1800, 1816, 1819, and 1822) that were unleashed in the wake of Cromwell’s invasion were, it turns out, only the warm-up for the big one that walloped the Irish in the 1840s.

The Great Irish Famine, as it’s known in America, would last much longer and hit much harder, largely because there was no export ban on Irish grain. The British were not only starving the Irish out, they were also fetchng their grain to sell off to the European armies. Not very neighborly of those Brits. How very impolite.

When the Connaught madhouse (now named St. Brigid’s) opened in Ballinasloe, just down the road from where my ancestors were in the parish of Cam-Kiltoom, it did much to relieve the local stress. Yet demand for services kept growing during the famine and continued with a sevenfold increase over the next 65 years, even as the population fell by half by emigration and death.

Ballinasloe was by no means the only madhouse in Ireland. St. Patrick’s in Dublin was the world’s first national mental institution, and a system of county asylums that sprouted all over Ireland was the single largest public works project under the British.

‘Never Again in a World of Plenty’

There were other factors conspiring to drive rates higher. Ireland had the oldest age of paternity among nations that recorded such things, and this was yet another direct consequence of the famine economy.

What people didn’t realize at the time was that late age of paternity can more than double risk of developing schizophrenia in the next generation.

The third leg of what I like to call my three-legged stool theory of Irish madness was, of course, alcohol. As strong as it was, drink was not nearly the driver that maternal malnourishment and older fathers were.

Of all three legs of my slightly wobbly three-legged stool theory of Irish madness, the alcohol leg is the shortest. All in all, it probably took all three to consummate our epigenetic warp.

It’s a worthy discussion if only because famine prevention can head off madness in future generations now. I’m reminded of that every time I ride my bicycle through Cambridge Common in Harvard Square.

There, in one corner, is a memorial to An Gortar Mor, inscribed with the chilling words: Never Again in a World of Plenty.