Proposals to give more rights to people with learning disabilities, autism and mental health conditions are to be unveiled by the government.
Care Minister Norman Lamb said the changes would put people in charge of their care, and promote community support as an alternative to hospital.
Mr Lamb admitted many families felt "their concerns are ignored".
Ministers pledged to move patients out of hospitals and into community care after the Winterbourne View scandal.
At Winterbourne View, a private hospital near Bristol, the BBC's Panorama programme exposed abuse of patients by staff in 2011.
Last month the National Audit Office said the government had failed to honour its pledge, because it had underestimated the "complexity and level of challenge" involved in discharging so many patients into the community.
Mr Lamb said his proposals, which are being put out to consultation, would strengthen people's rights to challenge decisions made about their care, and make it "much harder" to admit people to hospital when there was better support available in the community.
The consultation, to take place in England only, will also consider changes to the way the Mental Health Act applies to people with learning disabilities and autism.
Other measures could include having a named professional in charge of sharing information with an individual and their relatives, and a new duty for local authorities to check the amount of community support available for people at risk of being sent to hospital.
The Lib Dem minister said the reforms would improve accountability in the system, "so there can be no excuse for people falling through the gaps between services".
The Mental Health Act applies to England and Wales and any changes to the legislation would need to be agreed by Welsh government if they were to apply in Wales.
Future changes unrelated to the Mental Health Act would apply to England only.
He added: "This is fundamentally about transferring power to people and away from institutions.
"We have to end the horror of families feeling that they aren't listened to, that their concerns are ignored.
"Just because an individual is sectioned under the Mental Health Act shouldn't mean that the family is excluded."
In a joint statement, Jan Tregelles, chief executive of Mencap, and Viv Cooper, chief executive of the Challenging Behaviour Foundation, said: "We welcome the government's recognition that a serious imbalance of power exists within the system, leading to the voices of individuals and their families often being ignored, with devastating consequences."
But they warned that changes in the law "could take years" and are not guaranteed.