Money can’t buy happiness, as the adage goes. And a lot of us want to believe it. I’ve written two books about money, and over and over again, people cite to me a study from a decade ago that found earnings in excess of $75,000 annually had little impact on people’s daily state of mind.

As it turns out, people who trumpet that research ignore a major finding in it: People do express more satisfaction with their overall lives the more money they have on hand. They also ignore a more recent survey of millionaires, which found those with $8 million banked were happier than those with less than that amount.

A fascinating study released last month offers us another angle to consider in the money and happiness conundrum: It’s quite possible that the age of inequality has come for our happiness.

In a paper released last month by the journal Emotion, researchers Jean Twenge and A. Bell Cooper studied responses to questions about happiness from the General Social Survey. Looking at decades of people’s answers to questions such as whether someone was “very happy,” they found that “money and prestige do appear to buy happiness, and more is continuously better.” But there is a kicker: This was not a stable finding.

In the 1970s, people with different amounts of money experienced similar levels of happiness. But over time a gap developed, one that turned into something of a chasm. When Twenge spoke to The Post earlier this month, she speculated that inequality is a major reason.

Income inequality was not much of an issue in the early to mid-1970s, when the top 1 percent of households earned less than 10 percent of total income in the United States. But the income gap between the 1 percent and the rest is now at the highest level in 50 years, driven by everything from the decline of union representation among workers — unions not only bargain for better pay, but also for workplace protections — to the offshoring of jobs to increasing CEO pay.

The necessities of life didn’t come down in price to make up for the difference. Instead, they went up. Adjusted for inflation, the cost of attending college — either public or private — more than doubled. The same is true for buying a home. The price of health care soared so high that the typical employer-provided family plan now costs more than $20,000, and comes with a four-figure deductible. (The typical family only pays about $6,000 of it, but you can think of that other $14,000 as something you might otherwise see in your paycheck, if you are lucky enough to still have one.) And as two-earner families became the norm, there was a new, backbreaking expense that needed to be accounted for: child care, something that has risen in price such that in a majority of states, it costs more than attending public college.

What we call a “good life” got harder and harder for many to afford, leaving many to borrow more and more money — mortgages, student loans, credit cards, you name it. But it should surprise no one to discover that struggling with debt is correlated with greater levels of depression. One study, published in Social Science & Medicine in 2015, found those with student loans are more likely to experience “poorer psychological functioning.”

It’s not just that, as research shows, using money to buy our way out of tasks we find unpleasant — like housekeeping or cooking — increases our happiness level. It’s also that money buys privilege — the privilege of health (yes, the wealthy are healthier, and, yes, good health increases happiness), or, say, the privilege of working from home during a pandemic.

In the United States, we buy books on happiness, and we download apps that claim they will improve our mood. Yet all too many of us live in denial of the impacts of income and wealth inequality. When asked, we routinely overestimate the middle and lower classes’ share of the money pie, and we are more likely than those in countries with less inequality to tell pollsters that working hard is key to getting ahead in life.

In a society that is all but obsessed with the idea of happiness, I suspect it’s simply too painful to admit that our chances of achieving it are greater when our literal fortunes are greater, too.

Read more: