Here it explains "complex PTSD" from the link I posted.

It's widely accepted that PTSD can result from a single, major, life-threatening event, as defined in DSM-IV. Now there is growing awareness that PTSD can also result from an accumulation of many small, individually non-life-threatening incidents. To differentiate the cause, the term "Complex PTSD" is used. The reason that Complex PTSD is not in DSM-IV is that the definition of PTSD in DSM-IV was derived using only people who had suffered a single major life-threatening incident such as Vietnam veterans and survivors of disasters.

NOTE: there has recently been a trend amongst some psychiatric professionals to label people suffering Complex PTSD as a exhibiting a personality disorder, especially Borderline Personality Disorder. This is not the case - PTSD, Complex or otherwise, is apsychiatric injury and nothing to do with personality disorders. If there is an overlap, then Borderline Personality Disorder should be regarded as a psychiatric injury, not a personality disorder. If you encounter a psychiatrist, psychologist or other mental health professional who wants to label your Complex PTSD as a personality disorder, change to another, more competent professional.

It seems that Complex PTSD can potentially arise from any prolonged period of negative stress in which certain factors are present, which may include any of captivity, lack of means of escape, entrapment, repeated violation of boundaries, betrayal, rejection, bewilderment, confusion, and - crucially - lack of control, loss of control and disempowerment. It is the overwhelming nature of the events and the inability (helplessness, lack of knowledge, lack of support etc) of the person trying to deal with those events that leads to the development of Complex PTSD. Situations which might give rise to Complex PTSD include bullying, harassment, abuse, domestic violence, stalking, long-term caring for a disabled relative, unresolved grief, exam stress over a period of years, mounting debt, contact experience, etc. Those working in regular traumatic situations, eg the emergency services, are also prone to developing Complex PTSD.

A key feature of Complex PTSD is the aspect of captivity. The individual experiencing trauma by degree is unable to escape the situation. Despite some people's assertions to the contrary, situations of domestic abuse and workplace abuse can be extremely difficult to get out of. In the latter case there are several reasons, including financial vulnerability (especially if you're a single parent or main breadwinner - the rate of marital breakdown is approaching 50% in the UK), unavailability of jobs, ageism (many people who are bullied are over 40), partner unable to move, and kids settled in school and you are unable or unwilling to move them. The real killer, though, is being unable to get a job reference - the bully will go to great lengths to blacken the person's name, often for years, and it is this lack of reference more than anything else which prevents people escaping.