Which of the following is a symptom of Post-Traumatic Stress Disorder (PTSD)?

Flashbacks and nightmares are hallmark symptoms of Post-Traumatic Stress Disorder (PTSD). Individuals who have experienced a traumatic event may relive that experience through intrusive memories or vivid recollections, leading to intense emotional distress. Nightmares about the event can disrupt sleep and contribute to anxiety and hyperarousal, which are also common in PTSD. These symptoms are key indicators of the disorder, as they signify the profound impact that trauma can have on an individual’s mental health and daily functioning.

The other options represent emotional or behavioral states that are generally not associated with PTSD. Increased focus and productivity, consistent happiness and satisfaction, and improved communication skills suggest a state of well-being that is contrary to the experiences of those suffering from PTSD, who often struggle with various negative emotions and disruptions in daily life.