The International Classification of Diseases (ICD) identifies complex PTSD as a separate condition, though the DSM-5 currently does not.
Complex PTSD is a relatively recent concept. Because of its variable nature, healthcare professionals may instead diagnose another condition. They may be especially likely to diagnose (BPD).
Some researchers have areas of substantial overlap between complex PTSD and BPD.
However, the conditions may also have differences. Authors of a reported that, for example, people with complex PTSD had consistently negative self-conceptions, while people with BPD had self-conceptions that were unstable and changing.
People with complex PTSD may experience difficulties with relationships. They tend to avoid others and may feel a lack of connection.
BPD can cause a person to swing between idealizing and undervaluing others, resulting in relationship difficulties.
It is possible for a person with BPD to also experience complex PTSD, and the combination may result in additional symptoms.