Facilitated acquisition of the classically conditioned eyeblink response in active duty military expressing posttraumatic stress disorder symptoms.

OBJECTIVE: Learning diathesis models underscore the role of hyper-conditioning in the development of PTSD following trauma exposure. Eyeblink classical conditioning is one method of examining associative learning biases independent of fear and threat produced by trauma. Facilitated learning is apparent in individuals self-expressing PTSD symptoms, as well as behaviorally inhibited (BI) temperament, a vulnerability factor for PTSD. Here, we examine eyeblink conditioning in active duty military personnel and relate learning with PTSD symptomology. METHOD: Volunteers were 83 active duty United States Coast Guard personnel (18 females) recruited from small boat stations. Personnel were administered the PTSD Checklist (PCL) to assess current PTSD symptoms using DSM-IV criteria. BI temperament was assessed with the Adult Measure of Behavioural Inhibition (AMBI). Eyeblink conditioning was conducted using a partial reinforcement schedule, whereby paired trials (500-ms pure tone conditioned stimulus co-terminating with a 50-ms air-puff unconditional stimulus) were interpolated with 50% CS-alone trials. RESULTS: Consistent with previous work, there was a high degree of concordance between BI and incidence of PTSD. Further, PTSD was associated with faster learning during the acquisition period, with conditioned responding sustained through the extinction period. CONCLUSIONS: These results reinforce the relationship between BI and PTSD in an active duty military sample, supporting previous observations in veteran and civilian samples. The conditioning data are consistent with predictions derived from a learning diathesis model of stress and anxiety, suggesting facilitated associative learning may represent an additional vulnerability for the development and maintenance of stress-related pathology.

Stress-Related Mental Health Symptoms in Coast Guard: Incidence, Vulnerability, and Neurocognitive Performance.

U.S. Coast Guard (CG) personnel face occupational stressors (e.g., search and rescue) which compound daily life stressors encountered by civilians. However, the degree CG personnel express stress-related mental health symptoms of posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) is understudied as a military branch, and little is known concerning the interplay of vulnerabilities and neurocognitive outcomes in CG personnel. The current study addressed this knowledge gap, recruiting 241 active duty CG personnel (22% female) to assess mental health, personality, and neurocognitive function. Participants completed a battery of scales: PTSD Checklist with military and non-military prompts to screen for PTSD, Psychological Health Questionnaire 8 for MDD, and scales for behaviorally inhibited (BI) temperament, and distressed (Type D) personality. Neurocognitive performance was assessed with the Defense Automated Neurobehavioral Assessment (DANA) battery. Cluster scoring yielded an overall rate of PTSD of 15% (95% CI: 11-20%) and 8% (95% CI: 3-9%) for MDD. Non-military trauma was endorsed twice that of military trauma in those meeting criteria for PTSD. Individual vulnerabilities were predictive of stress-related mental health symptoms in active duty military personnel; specifically, BI temperament predicted PTSD whereas gender and Type D personality predicted MDD. Stress-related mental health symptoms were also associated with poorer reaction time and response inhibition. These results suggest rates of PTSD and MDD are comparable among CG personnel serving Boat Stations to those of larger military services after combat deployment. Further, vulnerabilities distinguished between PTSD and MDD, which have a high degree of co-occurrence in military samples. To what degree stress-related mental healthy symptoms and attendant neurocognitive deficits affect operational effectiveness remains unknown and warrant future study.