Bullying and PTSD
The traditional definition for post traumatic stress disorder (PTSD) indicates that there is one single traumatic event which caused a threat of or actual death or serious injury. However, recent research has shown that experiencing a series or prolonged episodes of trauma can also cause symptoms of PTSD. This is considered complex post traumatic stress disorder.
According to the Department of Veterans Affairs, victims of complex PTSD are "generally held in a state of captivity, physically or emotionally."  Long term situations involving abuse, concentration camps, prisoner of war camps and prostitution brothels are all situations that leave the victim feeling helpless and unable to get away from the perpetrator.
A recent study in Norway showed victims of bullying can also show long-term symptoms of PTSD. According to the study, approximately one-third of children who were bullied showed signs of PTSD.  Bullying is often carried out over an extended period of time, making the victim feel powerless to stop the barrage of emotional or physical abuse. With the onset of social media, cell phones and other electronic communication devices, cyberbullying often follows a child home, giving him or her no safe refuge.
Symptoms of Complex PTSD
Besides symptoms of avoidance, intrusive memories and flashbacks, chronic PTSD may include the following symptoms:
Persistent sadness, suicidal thoughts
Explosive anger or inhibited anger
Feelings of dissociation
Repression of memories of traumatic events
Reliving traumatic events
Feeling helpless, guilty or feelings of shame
Becoming preoccupied with revenge
Believing the perpetrator has power over him or her
Inability to feel trust for others
Many schools today are more aware of the effects of bullying and have anti-bullying programs in place. Teachers and other school officials are more sensitive to the needs of children who have been bullied and make take steps not only to stop the bullying but to offer support to the victim. But researchers involved in the study in Norway believe that assistance to the victims may stop too soon. Thormod Idsoe, lead researcher states, ""adult responsibility isn't confined to stopping the bullying. It also extends to following up on the victims"PTSD symptoms could persist for a long time with some children"It's important to monitor how pupils develop after being bullied and to be aware of the possibility that they might develop PTSD symptoms." 
Treatments for complex PTSD are the same as those for PTSD - therapy, including cognitive behavioral therapy and exposure therapy and medication if needed. Care should also be given to address any of the additional symptoms, such as interpersonal difficulties. Victims of chronic trauma may need to find ways to feel some control over their lives. In his book, Trauma and Recovery: The Aftermath of Violence from Domestic Abuse to Political Terror, Dr. Herman says, "Survivors can become empowered by healing relationships which create safety, allow for remembrance and mourning and promote reconnection with everyday life." 
  "Being Bullied Can Cause Trauma Symptoms," 2012, Nov 27, Staff Writer, ScienceDaily.com
 "Complex PTSD," Updated 2012, Aug 22, Staff Writer, U.S. Department of Veterans Affairs
"Post-Traumatic Stress Disorder (PTSD)," Date Unknown, Staff Writer, U.S. National Institutes of Health
 Trauma and Recovery: The Aftermath of Violence from Domestic Abuse to Political Terror," 1997, J. Herman, Basic Books, New York