PTSD is a response to a traumatic event that involves actual or threatened death or serious injury. The magnitude of the threat or harm is subjective and based on the perceptions and interpretations of the individual (Souza & Spates, 2008). In addition, the individual responds to the event with feelings of fear, helplessness, or horror as a prerequisite for PTSD. Exposure to the traumatic event alone does not generate PTSD: there must be both exposure to the event and an emotional reaction that causes the individual to experience high levels of stress. In addition, the traumatic nature of an event depends on the individual because two people may be exposed to the same event but will react differently – one may develop PTSD and the other will not (Souza & Spates, 2008). PTSD manifests in a variety of ways, depending on the individual, and as such, it is difficult to predict the specific ways in which PTSD will affect someone. Police officers are among the occupational groups that have recorded higher rates of PSTD. This is because they are exposed to different traumatic events in the course of their duties. Many PTSD symptoms can impair the ability of police officers to perform their normal duties (Arnetz, Nevedal, Lumley, Backman & Lublin, 2009). The degree of impairment, however, depends on the severity of the PTSD and the specific type of symptom that the police officer exhibits. In most cases, however, PTSD directly or indirectly affects the judgment of police officers and their ability to react appropriately (Arnetz et al., 2009). This essay will explore the cause and effect of PSTD in police officers.