To clarify the time course of immune system activity during and after acute stressor exposure, this study collected immune measures from 31 men at 6 times (before. during, and after 2 common laboratory stressors: mental arithmetic with harassment or a cold pressor task). The 6-min stressor period was associated with increased self-report of pain and distress in both stressor groups and with increased systolic and diastolic blood pressure and heart rate in the mental arithmetic group. Increased natural killer cell activity in this group was observed during the task (2 and 5 min into the task) and 5 min after the task ended. A significant Group × Time effect was observed for lymphocyte proliferation to pokeweed mitogen, and a significant Group × Time × Dilution effect was observed for proliferation to concanavalin A. Inspection of the data suggested that this interaction was due to a reduction in proliferation in both stressor groups during the task period.

Background Projected changes to post-traumatic stress disorder (PTSD) diagnostic criteria in the upcoming International Classification of Diseases (ICD)-11 may affect the prevalence and severity of identified cases. This study examined differences in rates, severity, and overlap of diagnoses using ICD-10 and ICD-11 PTSD diagnostic criteria during consecutive assessments of recent survivors of traumatic events. Methods The study sample comprised 3863 survivors of traumatic events, evaluated in 11 longitudinal studies of PTSD. ICD-10 and ICD-11 diagnostic rules were applied to the Clinician-Administered PTSD Scale (CAPS) to derive ICD-10 and ICD-11 diagnoses at different time intervals between trauma occurrence and 15 months. Results The ICD-11 criteria identified fewer cases than the ICD-10 across assessment intervals (range −47.09% to −57.14%). Over 97% of ICD-11 PTSD cases met concurrent ICD-10 PTSD criteria. PTSD symptom severity of individuals identified by the ICD-11 criteria (CAPS total scores) was 31.38–36.49% higher than those identified by ICD-10 criteria alone. The latter, however, had CAPS scores indicative of moderate PTSD. ICD-11 was associated with similar or higher rates of comorbid mood and anxiety disorders. Individuals identified by either ICD-10 or ICD-11 shortly after traumatic events had similar longitudinal course. Conclusions This study indicates that significantly fewer individuals would be diagnosed with PTSD using the proposed ICD-11 criteria. Though ICD-11 criteria identify more severe cases, those meeting ICD-10 but not ICD-11 criteria remain in the moderate range of PTSD symptoms. Use of ICD-11 criteria will have critical implications for case identification in clinical practice, national reporting, and research.