Q.Six months after surviving a serious flood that destroyed her family's home, Lakshmi still gets sudden, vivid flashbacks of the rising water whenever it rains heavily, feels intensely on edge, and finds it hard to concentrate on her studies or daily routine. Identify the condition Lakshmi may be experiencing, and explain, using the chapter's description, why it develops and what its typical symptoms look like.

A disaster — a serious disruption of the normal functioning of human society, resulting in widespread material or environmental loss that cannot be dealt with immediately using the resources already available — can be natural, such as an earthquake, cyclone, tsunami or flood, or man-made, such as war. The trauma an individual experiences during a disaster can range considerably in severity: it may involve merely perceiving that such an event is happening nearby, or it may involve actually encountering the event directly, in a way that is genuinely life-threatening to the person themselves.

Either of these kinds of traumatic experience — mere perception of a disaster, or direct, life-threatening encounter with one — may, in some individuals, lead to the development of post-traumatic stress disorder (PTSD). The defining feature of PTSD, as described in the chapter, is that the person tends to re-experience the traumatic event through flashbacks, and continues to have overwhelming, intrusive thoughts about the event, even after a substantial period of time has passed since it actually occurred — the trauma, in effect, keeps replaying itself in the person's mind well beyond the point when the immediate danger has ended. This ongoing re-experiencing leaves the person emotionally disturbed, and it interferes with their ability to draw on appropriate, adaptive coping strategies in the course of ordinary, everyday activities — the disorder does not stay confined to memories of the original event, but spills over into a person's general day-to-day emotional and behavioural functioning. Clinically, PTSD tends to manifest in a recognisable pattern that combines maladaptive behaviour — such as depression — together with heightened autonomic arousal, meaning the body's stress-response system (linked to the sympathetic nervous system) remains in an unusually activated, 'on edge' state. …