What is post-traumatic stress disorder (PTSD) primarily characterized by?

Post-traumatic stress disorder (PTSD) is primarily characterized by a sustained emotional disorder that arises following a traumatic experience. This condition often causes individuals to re-experience the traumatic event through flashbacks or nightmares, leading to severe anxiety, hyper-vigilance, and emotional distress. The symptoms can persist long after the traumatic event has occurred, significantly impacting the individual's daily functioning and quality of life.

In contrast, regular anxiety due to daily stressors does not necessarily stem from a specific traumatic event and is usually more situational or transient. Temporary sadness from life changes reflects normal emotional responses to transitions and does not encompass the persistent and debilitating nature of PTSD. Increased happiness after traumatic events contradicts the fundamental nature of PTSD, which involves distress rather than emotional uplift. Thus, the distinguishing feature of PTSD is its lasting impact as a sustained emotional disorder resulting from trauma, making the first option the correct answer.