So now we know that "shell-shocked" was an appropriate description for how investors felt when the financial crisis of 2008 made their portfolios implode.

The question is whether the response was appropriate.

According to research just published in the Journal of Financial Therapy, nine out of 10 financial planners and advisers wrestled with post-traumatic stress disorder in the aftermath of the 2008 financial crisis, with 40 percent of the respondents reporting severe symptoms. Beyond simple negative emotions like anxiety, a clinical diagnosis of post-traumatic stress requires disturbances like the inability to concentrate at work or to sleep fitfully for more than a month.

Functionally, advisers were just like anyone else going through the crisis, they were second-guessing themselves and the moves they made. They had the added stress of angry, upset clients to boot.

In short, according to researchers Bradley Klontz and Sonya Britt of Kansas State University, "The financial planner feels responsible for their clients' financial welfare, is helpless to change economic events, and in many cases is terrified that his or her own financial health and that of his or her employees may be jeopardized as a result of dramatic drops in assets under management."

The researchers said advisers responded to the stress by moving away from buy-and-hold strategies in favor of "tactical asset management" strategies, where effectively they are managing money more actively based on current market cycles and economic conditions.

It also makes them more responsive to clients and customers, as the plaintive cry of "Don't just sit there, do something!" seems to be the popular action plan for every market move, no matter the direction or the cause.

It's precisely the same reaction many individual investors had, and it contributes to the statistics showing that investors have been heavy into bond funds and cash while the market climbed up over investor concerns to reach record highs over the last few years.

The problem with a shell-shocked reaction is that it is borne out of fear, and it creates a real issue for mutual fund investors because it tends to make them want to actively manage the active managers they are paying to run their money.

Say an investor gets into a fund with an active management strategy and high portfolio turnover.

Even if the shareholder hangs onto the fund for a lifetime, the underlying investment is anything but buy-and-hold.

When nervous investors start to act - or when their advisers are driven to act borne out of their fears from the past - the problem isn't so much "active management," but "reactive management."

Specifically, the decision-maker at the fund level starts actively managing their holdings, even as the fund manager is actively managing the market.

That may feel good, but there's a realistic question as to whether it is the best move over time.

After all, most market observers have noted that the twin devils for the average investor are fear and greed, and if post-traumatic stress is driving forward-looking investment decisions, then fear plays a big role in the process.

"Being disciplined is not the same thing as being inattentive, and buy-and-hold is not the same as 'Set it and forget it,'" said Steve Wood, chief market strategist at Russell Investments. "Individual investors can be very often their own worst enemy, so the likelihood that an individual is going to bring value to the portfolio is not terribly high.

The likelihood that an individual will bring damage to their portfolio is rather significant."

Ultimately, the problem is that investors won't know if they have damaged their portfolio until it's too late.

"Damage," of course, is a relative thing. If it means "less than the maximum returns," many investors would accept that if it comes with greater peace of mind and less stress.

If, however, damage means "insufficient returns to reach financial goals," it's not the course most investors want to set.

And the problem is that all investors can know today is that the moves feel good while they make them.

Ultimately, the study showed that financial advisers are, for better or worse, a lot like everyone else. They stress over money problems and not knowing how things will turn out, even as they take strong steps in the right directions.

Alas, it leads an investor, with or without an adviser, back to one basic investment conclusion, namely that since they can't completely avoid risk, and they can't be sure of which ones to take or avoid, they need to diversify and accept different kinds of risk, to balance out their portfolio with a mix of what feels right and what is uncomfortable or disquieting, but can act as insurance in case the comfortable investments prove to be a let-down.

Wood noted that investors must focus on the ultimate goal, namely what the assets are supposed to accomplish, and he worried that additional management based on nervousness would mean "that average investors probably will add a lot of volatility to their results, without adding a lot of acumen."

Sadly, if that's the result, all it's going to do is stress investors out even more.

cjaffe@marketwatch.com