An U.S. survey indicates depression or anxiety to be the main reason older adults -- baby boomers age 50 and older -- say they abuse drugs or alcohol.

A survey conducted by the Hanley Center found additional factors such as economic and financial stress and retirement were also cited as contributing factors to substance dependency. Nearly half of the respondents named prescription drugs and alcohol as their substances of choice, the survey said.

"Older adults face a distinct set of challenges as they enter their golden years," Dr. Barbara Krantz, medical director of Hanley Center, said in a statement. "This transitional period of life is unique and leads to difficulty in dealing with stressful situations, such as an early retirement or financial strains, which in turn may lead to serious anxiety and depression. Without the proper tools to manage their emotions, older adults turn to quick fixes such as alcohol and drugs, creating the perfect storm for dependency."

The survey, conducted anonymously among Hanley Center alumni, showed:

-- 79 percent of adults 48 and older said their first experience with drugs/alcohol occurred before the age of 25, 40 percent said they considered themselves to be substance abusers after the age 48.

-- More than 90 percent of respondents named alcohol as one of the substances they abused; 49.5 percent of respondents reported prescription drug abuse.

-- More than 40 percent of respondents said their families influenced their decision to seek treatment.