Post-traumatic stress disorder (PTSD) is characterized by symptoms such as flashbacks, anxiety, insomnia and depression. It results from the experience or witnessing of a tragic event. The event can be any kind of tragedy, from an assault to a car accident resulting in injury. Those diagnosed with PTSD may have varying symptoms. Some individuals are severely disabled in everyday activities while others are able to experience a lessening of symptoms through treatment. Symptoms for PTSD are generally assessed using the PTSD Checklist (PCL). The tool is considered effective at measuring the severity of symptoms that are known to be negative stress reactions. The PCL is useful in aiding clinicians with the process of diagnosis, as well as establishing a strategy for treatment. There are some patients, however, who do not meet the criteria for PTSD using the PCL but are at an increased risk for certain risky behaviors, such as substance abuse and aggression. While the PCL is effective at determining which patients have PTSD, it may not adequately address the needs of patients with borderline symptoms. Recently Dr. Janie M. Brown of the Research Triangle Institute International in North Carolina completed a study that attempted to evaluate the effectiveness of the PCL in identifying patients susceptible to negative stress responses. The study's focus was on the PCL's role in diagnosing military personnel. The study was conducted based on the understanding that soldiers who have been engaged in a battle zone are at a higher risk for experiencing a traumatic situation when compared with soldiers who have not had a deployment. The study involved 6,074 reservists and 8,354 active-duty military personnel. Each of the soldiers enrolled had been in a combat zone during the last two years. Each participant was evaluated for risk taking, alcohol consumption habits, impulsiveness, in addition to other behaviors often seen with negative stress reactions. The analysis showed that when a participant had a lower PCL score, they also exhibited lower levels of negative behaviors, such as violence, aggression and impulsivity. The finding was consistent across both reservists and active-duty personnel. One important finding from the study showed that even when patients did not meet criteria for PTSD, they might have significant levels of negative behaviors. The researchers found that it was possible for patients to be far below meeting the criteria and still have major issues with substance use and aggression. In addition, the findings showed that among the participants evaluated, the active-duty soldiers were more likely to exhibit negative behaviors than the reservists. The authors of the study note that even when military personnel do not meet the screening criteria for PTSD, they should still be screened for high-risk behaviors. The findings of the study are published in a recent issue of the journal Military Medicine.