Trauma and stressor related disorders include disorders in which exposure to a traumatic or stressful event is listed explicitly as a diagnostic criterion. These include reactive attachment disorder, posttraumatic stress disorder (PTSD), acute stress disorder, and adjustment disorders. Psychological distress following exposure to a traumatic or stressful event is quite variable. In some cases, symptoms can be anxiety or fear but many individuals who have been exposed to a traumatic or stressful event may be exhibit other symptoms like anhedonia, dysphoric, angry, aggressive or dissociative symptoms. Because of these variable expressions of clinical distress following exposure to catastrophic or aversive events, the aforementioned disorders have been grouped under a separate category in DSM-5. Differences between DSM-IV and DSM-5 about PTSD are: The essential feature of PTSD is the development of characteristic symptoms following exposure to traumatic events. Emotional reactions to traumatic event (e.g., fear, helplessness, horror) are no longer a part of Criterion A. The clinical presentation of PTSD varies. In some, fear based re-experiencing, emotional, and behavioral symptoms may predominate. In others, anhedonia or dysphoric mood states and negative cognitions may be most distressing. In some arousal and reactive-externalizing are prominent, while in others, dissociative symptoms predominate. Criterion A4 does not apply to exposure through electronic media, television, movies, or pictures, unless this exposure is work related. Criterion D (Negative alterations in cognitions and mood associated with the traumatic event) was added. PTSD can occur at any age, beginning after the first year of life. Symptoms usually begin within the first 3 months after the trauma but may be delay of months. There is abundant evidence for what DSM-IV called “delayed onset” but is now called delayed expression,” with the recognition that some symptoms typically appear immediately and that the delay is in meeting full criteria.