Flashbacks

Mak said that while some people return to normal, others don't. They may have flashbacks and general numbness. They may try to block related thoughts, withdrawing to the point where they no longer make eye contact with people.

He recalled a patient who recovered from SARS in 2003, but remained emotionally scarred.

During the outbreak, both the patient and her husband were infected. Her husband was seriously ill and was transferred to the intensive care unit unconscious, while the woman's condition was mild.

Both survived, but years later the woman started having flashbacks.

"Flashbacks are different from ordinary memories," Mak said. With normal memories people just recall what happened and acknowledge that it was in the past. People with flashbacks believe they're right there, going through the most frightening experiences in their lives in real time, he added.

The more the woman tried to force the memories from her mind, the more intense they became and she had bouts of shortness of breath. Flashbacks can lead to physical symptoms, including muscle tension, breathing difficulties, headaches, chest pains and gastrointestinal discomfort, he noted.