Of course, funds basically come with just one warning — "past performance is no guarantee of future results" — rather than the long list of symptoms that consumers are warned about with drugs, often a description so long and detailed that a squeamish consumer might prefer death to the unintended consequences of the medicine.

In funds, side effects typically are an offshoot of the types of funds being purchased or the strategy being followed.

Investors recognizing these symptoms in themselves, however, should sense that something is amiss and that a change in funds, strategy or attitude might solve the problem.

If your mutual-fund investments are giving you any of the following conditions, consider what you might do to feel better about your portfolio:

• Restlessness, insomnia, headache and indigestion. (Also increased sweating.)

These typically are the result of investing in funds that give you the willies. They might be too volatile, concentrated in a single industry or country, built on an asset type that tends to run from feast to famine or in an intriguing-but-scary category such as emerging markets.

Your fund portfolio shouldn't be making you nauseous or keeping you up at night. If it is, look at how you might calm things down so you can rest easier.

• Decreased investment drive (or difficulty picking another investment).

Many investors say they can stomach risk so long as they don't actually lose any money. When they actually see their shares fall in value they lose a lot of their desire to invest, because they question if they have the skills to make money in funds.

When one or more funds in a portfolio are not world beaters, that doesn't mean your fund-picking methods are flawed; it may just confirm the idea that even the best selection methods can't deliver big winners all the time.

• Double vision.

This side effect usually occurs when an investor has success in a fund and wants to diversify but instead adds only funds that buy similar assets. That keeps the portfolio in the investor's comfort zone, but it minimizes diversification and increases overall risk.

An investor who owns four funds within one fund category is likely to get the performance of an index tracking those assets, while paying higher-than-indexing costs. That's a mistake.

• Euphoria, prolonged dizziness.

Sometimes a fund pick goes so right that investors keep piling more and more money into it. This is what happened to many people at the peak of the bull market, when they went overboard on technology believing it would never come down.

As this feeling grows, investors tend to let their portfolio get out of balance. The feeling tends to go away only when the market turns, at which point it becomes more painful than a typical downturn.

Chuck Jaffe is senior columnist at Marketwatch. He can be reached at jaffe@marketwatch.com or Box 70, Cohasset, MA 02025-0070.

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