FORT WORTH, Texas (AP) _ First lady Nancy Reagan, in Texas for a visit by Britain's Prince Charles, handed out 11 diplomas Tuesday to graduates of a drug rehabilitation program, saying ''the best things in life don't come easy.''

''The past two years have been tough for you graduates ... but in sticking it out to the end, each of you has learned a lesson ... the best things in life are worth working for,'' Mrs. Reagan said.

Mrs. Reagan visited the Cenikor Foundation, a non-profit program that provides treatment and education for people with drug and alcohol problems.

Before the ceremonies, the first lady participated in a group session with 10 members of Texas War on Drugs, an anti-drug abuse group, and clients at Cenikor.

''If we can get all the young people involved (in preventing drug abuse), we've got a big leg up,'' Mrs. Reagan said. ''We need all these young people, but we need you clear-eyed and clear-headed. We don't need you all drugged up.''

Members of Texas War on Drugs are mostly high school students who visit schools to speak against using drugs.

Karl Dunn, a Cenikor resident, said solving the drug abuse problem is his chief goal in life.

''It's nice to know that someone is running the front line, because it's needed,'' he said.

Kathy Weatherford, another resident, said she was a longtime drug user before entering the program. ''I ended up in Cenikor because I had been convicted of felony theft,'' she said.

About 50 percent of Cenikor residents are referred to the program by courts, said Tyrone Evans, assistant to the president of Cenikor. The program currently has 450 residents, who receive up to 30 months of treatment, Evans said.

Mrs. Reagan also was given an honorary degree by Ed Fresquez, Cenikor president, for her efforts against drug abuse. During the ceremony, she read a letter from a woman whose daughter had died of drug abuse.

''Our beautiful 24-year-old was so powerfully influenced by drugs that she took her own life ... So sign me off as a mother who never has to worry about her phone ringing in the middle of the night. What a price we paid for sleep,'' Mrs. Reagan quoted from the letter.