A Wall Street stock market shrink says the mood of the market, which has been manic all year, could be transitioning to a more depressive, downbeat mood.

Story Highlights

Expert in market psychology warns that sure-thing story poses risk History-making run-up is rare, raising odds of a severe correction The markets recent increase in daily price swings could be signaling trouble ahead

NEW YORK — The mood of the stock market, manic and upbeat for most of this year, might very well be transitioning to a more depressing, downbeat state of mind.

That’s the diagnosis from Woody Dorsey, a self-described master of market psychology. Dorsey is president of Market Semiotics, a research firm that analyzes the market’s manic-depressive behavior from a psychological viewpoint from the picturesque New England town of Castleton, Vt. a 243.3-mile drive from Wall Street’s frenetic trading floors.

In many ways, Dorsey is a market shrink. He analyzes what the stock market’s state of mind is during its many cycles.

His goal: decipher if the market is in stable condition and in a good state of mind, or whether it is starting to exhibit signs of unstable behavior that could be pointing to a breakdown.

His line of work is especially helpful during periods like now, when both stock prices and investor sentiment appear to be at, or nearing an extreme. And where price swings start to get wild, as they have in the Dow Jones industrial average, which has seen 100-plus point moves in 17 of the past 18 trading sessions. Friday, it fell 106 points to 15,070 .

It is during major extremes when markets tend to change direction most dramatically. And right now the stock market, after racing ahead 15% this year, its fastest start since 1987, is still trading a tad below record levels. And, not too surprisingly, investor optimism has been on a steady rise, becoming more exuberant.

The combination of a hot market and a growing herd of believers in the rally could be adding up to trouble for stocks, Dorsey warns. The market’s flagging momentum the past few weeks since the Federal Reserve hinted that it could soon start paring back on its market-friendly bond-buying program, coupled with growing volatility both in U.S. markets and foreign markets like Japan, could be signaling that stocks might be carving out a top and the long-awaited pullback is underway.

Dorsey’s diagnosis: The market is in the late stage of a mania. There could be more gains to come. But the resolution will be a very severe correction. And I think it will happen in the next few months.

So what troubling symptoms worry Dorsey?

• Bullish storylines. The market has been melting-up, thanks to a a series of bullish and recurring story lines, or what Dorsey calls rationalizations for why stock prices will keep rising. The script includes concepts such as the notion that central banks will do whatever it takes to ensure the market won’t suffer a 2008-style collapse. That meme went viral last July when European Central Bank chief Mario Draghi used those words in a key speech that reduced fears of a eurozone collapse.

Another popular meme is the notion that with interest rates, or yields, on cash and bonds at or near historic lows, that there is no other place for investors in search of decent gains to put their money. This is the so-called TINA trade, or There Is No Alternative to stocks, coined by investment firm Strategas Research Partners.

Similarly, there’s the FOMO, or Fear Of Missing Out trade. That is the belief among money managers and other investors that if they’re not invested in stocks they will miss out on gains. Or the belief that it’s a no-brainer to own dividend-paying stocks. Or Japanese stocks. Or that interest rates will never rise again.

Dorsey says these themes are similar to the go-go 2000 tech-stock era, which he dubs E-Greed. Or the 2007 period when everyone thought home prices could never go down. Or the exact opposite of 2009 when scared investors were gripped by the fear story line and thought stocks would never rise again.

As a result, You have this whatever it takes, stocks are the only place to be, you can’t lose mentality, Dorsey says.

The problem: It creates a big extreme in prices, which increases market risk. People get very excited. In short, People can see only one side of the equation, says Dorsey.

• History-making moves. Record highs in the stock market, by their nature, are historic. And what is historic is very unusual, in that it doesn’t happen very often. The fact that central bankers around the world have cut interest rates 515 times in the past six years times, according to Bank of America Merrill Lynch, is also very unusual. As is the fact that stocks are off to their best start in more than 25 years.

It is an outlier, says Dorsey, adding that rare occurrences also have consequences or outcomes that are unpredictable.

• Parallels to past drops. Dorsey is not predicting a crash, but rather an extreme re-pricing of stocks or a severe correction. He says there are parallels to 1987, when stocks famously crashed. Back then, yields on the 10-year Treasury note rose sharply, from around 7% at the start of the year to 8% and then 9% that summer as stocks kept rising. By the time the Dow crashed that October the yield on the 10-year Treasury note had topped 10%.

Investors, of course, are currently worried again that rates will rise sharply in anticipation of the Fed dialing back in its bond-buying program, which has been in place for more than four years and which has pushed down rates artificially. The 10-year note last week topped 2.2%, up from around 1.64% in May, and set a 14-month high.

Dorsey says the stock market is in a bubble. He says the risk is that when the market turns everyone has to get out because there is no one else to buy.

For that to happen, he says, you need a change in investor sentiment, a change in the direction of stock prices and the realization that the market has a new story driving it.

When people realize something has changed, that is when they will decide to sell, says Dorsey.