Short answers, pulled from the story.
A man named Jan-Erik Olsson held four people hostage inside a bank vault in Stockholm starting on the 23rd of August 1973. The hostages developed a strange attachment to their captors and refused to testify against them by the 28th of August 1973. Swedish criminologist Nils Bejerot labeled this behavior as a new psychological condition without ever speaking to the people it described.
Swedish criminologist Nils Bejerot coined the term Norrmalmstorgssyndromet or the Norrmalm Square syndrome in 1973. The original incident began on the 23rd of August 1973 when Jan-Erik Olsson held four people hostage inside a bank vault in Stockholm. Bejerot claimed the hostages were brainwashed by their captors despite never meeting them during or after the incident.
The Diagnostic and Statistical Manual of Mental Disorders has never included Stockholm syndrome as a distinct disorder. A 1999 report by the FBI found that only 8% of kidnapping victims showed signs of Stockholm syndrome and the percentage dropped to 5% when negative feelings toward law enforcement were excluded. Researchers like Namnyak et al. in 2008 found that there has not been much research into the phenomenon and what little has been done is often contradictory.
Patty Hearst was taken by the Symbionese Liberation Army in 1974 and eventually began to denounce her family and the police. Her defense lawyer F. Lee Bailey attempted to use the concept of Stockholm syndrome as a defense in 1975 but the term was too new and the evidence too weak to sway the court. The case highlighted the difficulty of distinguishing between genuine psychological bonding and strategic survival.
Lima syndrome is an inversion of Stockholm syndrome in which abductors develop sympathy for their hostages. The concept was named after an abduction at the Japanese embassy in Lima, Peru, in 1996 when members of a militant movement took hostage hundreds of people. The main example for research on this variation came from the Japanese embassy hostage crisis in Lima where spending time with the captives may have strengthened the bonds between the captor and captive.