While disaster-preparedness training is generally seen as a good idea in terms of improving the immediate physical safety and logistical issues involved with a traumatic event, such training may also provide important preventive factors against developing PTSD. That is as evidenced by the fact that those with more professional-level training and experience (for example, police, firefighters, mental-health professionals, paramedics, and other medical professionals) tend to develop PTSD less often when coping with disaster than those without the benefit of such training or experience. People who have been traumatized but are not members of those professions have been found to be less likely to develop PTSD if they receive imaging exposure and therapeutic processing by trained professionals within a day of the trauma and weekly sessions for at least two weeks thereafter. There are medications that have been found to help prevent the development of PTSD. Some medicines that treat depression, decrease the heart rate, or increase the action of other body chemicals are thought to be effective tools in the prevention of PTSD when given in the days immediately after an individual experiences a traumatic event.