ABSTRACT
Assessing PTSD by questionnaire can lead to false positive diagnosis after severe traumatic brain injury. Sumpter and McMillan, reported quantitative data on 34 people with severe TBI; 59% were PTSD 'cases' by questionnaire assessment, but only 3% using a structured interview. The present paper describes ways in which these individuals made errors on questionnaires. Some did not follow questionnaire instructions because of inattention and concrete thinking or instead reported effects of brain injury. Symptom overlap between TBI and PTSD, including insomnia, irritability and impaired concentration can cause errors. Brain injury can also provoke curiosity about loss of memory (during coma, retrograde and post-traumatic amnesia), decreased participation, social withdrawal and difficulty adjusting to injury that may be mistaken for fear-associated PTSD symptoms. Assessment of PTSD by questionnaire can lead to erroneous conclusions and factors related to brain injury must be carefully considered when investigating PTSD.
