As patients and partisans of all stripes take a deep breath after the latest Republican effort to dismantle Obamacare, they might consider how trying to save health-care dollars can have unintended consequences.

In the Netherlands,  the government sought to give people more "skin in the game" in its national health system. The idea —  long supported by U.S. conservatives, even for poor people on Medicaid — is that when patients have to shell out some cash for their care, they won't seek  unnecessary services.

In 2012, the Dutch government imposed mandatory co-payments for mental-health care on adults but not children, effectively creating two groups that researchers could compare.

The result: Adults' use of regular mental-health services abruptly dropped 13.4 percent for both severe and mild disorders. The decline was even sharper for poor people. For children, who had no co-pay, there was no appreciable change.

The next development: Involuntary commitments for mental-health crises in adults doubled.

The net effect: Just of three-tenths of 1 percent was saved the first year, and the national health system abandoned the co-pays.

What's the takeaway for American health care?

"Without careful planning and oversight, mental-health cost-sharing programs may exact a steep price," Benjamin G. Druss, a professor at Emory University's Rollins School of Public Health, wrote in a commentary that accompanied the research article in  JAMA Psychiatry on Wednesday.

Changes to the Affordable Care Act as well as the long-standing Medicaid program that many Republicans in Washington want to make would lead to sharp cuts in federal spending. That would force states into some mix of boosting taxes, cutting enrollment in Medicaid, and requiring beneficiaries to pay more.

The GOP proposals, currently on life support after key defections this week by both moderates and conservatives, did not get as specific as raising cost-sharing, which could include co-payments (specific dollar amounts that patients pay for each office visit or prescription), co-insurance (the same thing but based on a percentages), or deductibles (the amount patients must pay before insurance kicks in). But increasing patients' skin in the game has long been part of the GOP emphasis on personal responsibility.

And while the party's plans were imploding in Washington, House Republicans in Harrisburg last week quietly passed and sent to the Senate a bill of their own that could increase co-payments for Medicaid recipients as well as impose work requirements and make other changes that health-care advocates worry would discourage enrollment. Gov. Wolf opposes the bill, but a veto could disrupt legislation on the budget, which already is at a standstill.

The latest study, from researchers at Harvard and in the Netherlands, adds to growing findings that there's no simple way for consumers to drive down health-care costs by shopping for the best price. It typically is impossible for Americans to determine prices of many medical services ahead of time. Nor can they always tell which problems require urgent treatment, which can be skipped, or even which treatments are best.

Previous studies have found that increasing cost-sharing causes consumers to skip medical care somewhat indiscriminately. The Dutch research was the first to examine the impact of cost-sharing changes on specialty mental health-care, the authors wrote.

Jalpa A. Doshi, a researcher at the University of Pennsylvania's Leonard Davis Institute of Health Economics, has examined how Americans with commercial insurance respond to cost-sharing for antidepressants.

"Because Medicaid is the largest insurer of low-income individuals with serious mental illnesses such as schizophrenia and bipolar disorder in the United States, lawmakers should be cautious on whether an increase in cost sharing for such a vulnerable group may be a penny-wise, pound-foolish policy," Doshi said in an email after reading the new study.

Michael Brody, president and CEO of Mental Health Partnerships, formerly the Mental Health Association of Southeastern Pennsylvania, had an even stronger reaction about the possible implications for Medicaid patients.

"Folks in Harrisburg and in Washington continue not to recognize that the reason you are on this benefit is you meet certain economic tests," Brody said.  "Having to make choices" between mental-health care that requires co-pays "or food or keeping the lights on, the likelihood is that they are going to choose the latter and because they are not getting routine care their condition is going to deteriorate and they are going to make use of higher-cost services," he said.