First of two parts.

Rosanne Murphy was growing more agitated as she sank deeper into Alzheimer’s disease. Unable to bathe, dress, or feed herself, she would call her daughter in a panic many nights at bedtime, not remembering where she was.

It was time, her daughter, Alison Weingartner, realized - time for her mother, then 80, to move to a nursing home.

Over two months in early 2006, she visited 10 facilities, trying to make sure she picked the right one. Weingartner finally chose Ledgewood Rehabilitation and Skilled Nursing Center in Beverly because it had an Alzheimer’s special care unit and it was near her home. She could visit her mother often.

She knew what she liked about the home; it’s what she had no way of knowing that now haunts her.

Ledgewood is one of many nursing homes that have commonly used antipsychotic drugs to control agitation and combative behavior in residents who should not be receiving the powerful sedatives. Nineteen percent of such Ledgewood residents - those without a diagnosis for which the drugs are recommended - received the medications, anyway, exposing them to the risk of dangerous side effects.

Soon Weingartner’s mother would be one of them, starting a downward spiral that would include an increasing number of falls and seizures.

“There is a lot of guilt about putting your mom in a nursing home, and I felt I made a competent choice,’’ Weingartner said. “I wish that what I know now, I would have known then.’’

The situation she encountered at Ledgewood is alarmingly common in Massachusetts and across the nation, a Globe investigation has found. Federal data show that roughly 185,000 nursing home residents in the United States received antipsychotics in 2010 contrary to federal nursing home regulators’ recommendations - often elderly people like Murphy who have Alzheimer’s or other dementias.