Here's a lesson from Intervention 101: Those in relationships with addicts must stop enabling destructive behavior. Enabling only sends the message that dangerous, negative behavior is fine, and always includes a cushy safety net or even positive reinforcement when things go wrong. What does this have to do with investing? Plenty.

Such principles apply to the relationship between shareholders and those who are charged with the responsibility of being good stewards of the companies that shareholders have ploughed their money into: corporate managements and boards.

When corporate managements and boards become addicted to power, they take advantage of shareholders over and over, even when it's clear they're behaving in ways that destroy shareholder value.

Putting a stop to such behavior requires the will power to quit enabling it. It's time for some tough love in the investing world.

Pushing for rehab
Carl Icahn has quite an interesting bio and history in the investing realm, but he's often gone to bat to try to establish better corporate governance policies at public companies that sorely need a major shareholder intervention.

One of Icahn's current targets is Forest Laboratories (NYSE: FRX), which makes the antidepressant Lexapro. For the second year running, Icahn has nominated a set of four directors to replace current ones on Forest Labs' board.

Icahn's complaints include the company having overcompensated CEO Howard Solomon for years running, despite corporate underperformance that even included lawsuits accusing the company's directors of having breached their fiduciary duties.

Today, Icahn has accused Forest management of hiding poison-pill provisions in licensing agreements. Poison pills help companies attempt to block potential mergers and acquisitions.

Forest claims in a recent Form 10-Q that it's making some real efforts to strengthen its corporate governance policies, such as "measures related to conflicts of interest regarding board discussions, compensation consultants, and executive compensation policy, as well as payment of certain agreed legal fees of the plaintiffs" in shareholder litigation.

Granted, there is one concrete development along these lines so far: CEO Solomon requested no base salary boost this year. Still, there's little reason for any real depression on his part; last year his total compensation was valued at $8.5 million. Beyond that, the company has a lot of work to do to produce some concrete plans to assuage concerned or even outraged shareholders.

Forest's annual meeting takes place next week, so it should be interesting to see whether Icahn's complaints are backed up by shareholder votes. If investors know what's good for them, they'll take the controversy seriously as they weigh the decisions on their proxy ballots.

Battling for better boards
Forest Laboratories isn't the only place Carl Icahn has recently made a ruckus for better boards. He helped in a much-needed shareholder insurrection at Chesapeake Energy (NYSE: CHK), managing to place a director on its board. That company also replaced its chairman after a shocking litany of serious, highly publicized incidents related to CEO Aubrey McLendon's tenure. Icahn also managed to place a director on the board of WebMD.

If board shakeups don't sound like a significant component of long-term shareholder value, think again. A recent study conducted by James Drury Partners showed that stocks of the companies it defined as having better boards outperformed those with weaker boards significantly.

This was illustrated by shares of companies the firm identifying as having stronger boards, such as Mastercard (NYSE: MA), rising 29% over a five-year period, while those it marked as having weaker boards, such as Microsoft (Nasdaq: MSFT), rose only 16% during the same timeframe.

Interestingly, Carl Icahn's own public company, Icahn Enterprises (Nasdaq: IEP) came in at the bottom of this particular report's findings. Icahn pointed out that his company is a general partnership as opposed to a corporation, and therefore is structured differently.

Furthermore, Reuters provided his rebuttal regarding the report's findings: "I do believe that the whole structure of corporate governance in this country needs drastic changing, but not in the way this survey implies. You don't need larger boards. You need better boards."

Vote against abuse
For far too many years, too many corporate managers have seemed drunk on power and money and directors seemed metaphorically passed out in a fog of complacency, rubber-stamping the behavior. Meanwhile, investors weren't helping either; short-term focus and obsessing on near-term stock prices instead of management and board quality are the epitomize enabling bad behavior.

Fortunately, shareholder interventions are taking place and gathering steam. Laying down the rules and voting to end the abuse is the perfect prescription to heal a major component of corporate America's dysfunction.

Check back at Fool.com for more of Alyce Lomax's columns on environmental, social, and governance issues.