Former Colombian rebel captive John Freddy Diaz knows something that recently freed hostages may just be discovering: The pain of a kidnapping doesn't end with liberation.

Seven years after his release, the tall, 31-year-old former army private hardly works and feels bitterly alienated. He says he's prone to self-injury and fits of violence against strangers.

"I've had lots of crises," said Diaz, who was held captive for three years _ far shorter than most. He sobbed as he admitted to occasionally beating his head against walls and "trying to hit people I don't even know."

Colombians plan a nationwide march Sunday to demand the liberation of dozens of hostages still held by the Revolutionary Armed Forces of Colombia, or FARC, the country's main rebel army. Many have been held for more than a decade.

In the last six months, 21 prisoners have been released or rescued. They include 15 freed July 2 in a dramatic military mission that tricked the FARC into giving up its most valuable hostages _ former presidential candidate Ingrid Betancourt and three U.S. military contractors.

Many will face a life of disorientation, insomnia and panic, not to mention broken marriages and strained family relations, mental health professionals say.

"Victims leave a kidnapping psychologically disoriented in a big way, and it increases according to the intensity and length of their captivity," said Ismael Roldan, former director of the National University's department of psychiatry.

Betancourt has said that she's not yet ready to discuss painful details of more than six years in FARC hands.

"Many things happened in the jungle that we have to leave in the jungle," she said.

The former hostages represent just a sliver of the 12,298 people kidnapped by the FARC and the National Liberation Army, or ELN, in the last 12 years, according to Pais Libre, a kidnap victims' advocacy group. Most were freed for ransom payments that help finance the rebels' military operations.

The government says the FARC still holds about 700 hostages, but no one knows for sure. The count includes people seized as far back as 1996, many of whom were never heard from again.

The FARC captured Diaz in 1998 when it overran a military base in the southern jungle town of Miraflores, killing his younger brother, Diego, among others. He was freed with 241 comrades in 2001.

"They humiliated us, chained us, mistreated us physically and mentally," said Diaz, who in 2006 spent a month in a mental hospital.

"Before he was kidnapped, John was very active, very happy," said his aunt, Lucy Diaz. "When he returned he initially had a lot of spirit, energy to do a lot of things. But little by little he shut down and now he has little motivation."

Diaz celebrated the July 2 military rescue. But when he heard Betancourt might be nominated for the Nobel Peace Prize, he was upset.

"They should nominate all of us," he said.

Sunday's marches, to be held in major cities, were proposed by a newly released hostage, police Sgt. Julio Cesar Buitrago, to call attention to others left behind. Continued...