Diagnosis will be made by means of structured interviews to enhance diagnostic reliability and interview validity. An assessment battery to establish baseline measures of PTSD symptomatology, mood state and global functioning will be performed approximately two weeks before the onset of treatment and will consist of the following diagnostic instruments:

1. Structured Clinical Interview for the DSM-IV: SCID-IV (First et al, 1994). The SCID is a semi-structured interview that permits accurate diagnosis of life-time and current psychiatric disorders using DSM-IV criteria.
2. Clinician-Administered PTSD Scale: CAPS (Blake et al, 1990). The CAPS is a structured interview designed specifically for the assessment of PTSD. It assesses the seventeen symptoms of PTSD along with eight associated features. Forms 1 and 2 will be given to measure current and lifetime PTSD diagnosis (CAPS-1) and CAPS-2 allows for the assessment of PTSD symptom status over time.
3. Impact of Events Scale: IES (Horowitz et al, 1979). The IES is a 15-item self-report scale designed to measure the extent to which a given stressful life event produces subjective distress.
4. Symptom Checklist 90: This is a standardized instrument used to measure subjective feeling states.
5. NEO Personality Inventory: (Piedmont, 1998). This model of personality structure provides insight as to the internal psychological forces that have resulted in Axis I psychopathology. In the current study of MDMA-assisted therapy with people with PTSD, perceived strength of the therapeutic alliance and the rapport between participant and therapist will be assessed with the measure below. This measure will be administered once during the second introductory session and again during the follow-up therapy session occurring after each MDMA session.
6. Working Alliance Inventory: WAI (Hovrath and Greenburg, 1989). The WAI is a 36-item self-report scale designed to assess the quality of the working alliance existing between participant and therapist. The measure listed below will be used to assess subjective distress during the course of each MDMA-assisted session:
7. Subjective Units of Distress: SUDS. This is a standardized subjective rating scale by which a subject can quickly rate comfort level throughout the session. In the current study, the following measures will be administered at baseline and again after both MDMA-assisted sessions to measure neurocognitive function in specific domains selected to assess memory and attention, two areas found to be affected be regular Ecstasy use (Fox et al, 2001; Gouzoulis-Mayfrank et al, 2000; Morgan, 1999; Rodgers, 2000).
8. The Repeatable Battery for the Assessment of Neuropsychological Status: RBANS (Randolph, 1997). This assessment measures change in a patient's neuropsychological status over time. The domains assessed include: Immediate Memory, Visuospatial/Constructional, Language, Attention, and Delayed Memory.
9. The Paced Auditory Serial Addition Task: PASAT (Roman et al 1991). This assessment is a sensitive measure of information-processing speed and efficiency, concentration skills, and immediate memory.
10. Rey-Osterrieth Complex Figure: (Mitrushina et al, 1999). This measures visuoperceptual skills, spatial organizational skills, and memory.