Posttraumatic stress disorder (PTSD) is a severe anxiety disorder triggered by experiencing or witnessing a traumatic event, such as an accident, war, unexpected death of a loved one or serious assault. The intense fear and horror associated with such traumatic events is expected to cause strong reactions in most people, including nervousness, anger and fear. Usually, these reactions decrease over time. For people suffering from PTSD, however, these reactions persist or even increase over time, causing a significant impairment in daily functioning and social interactions. Mental health experts estimate that approximately 25-30% of individuals exposed to a traumatic event go on to develop PTSD.
Symptoms of PTSD
Symptoms of PTSD usually start within three months of the traumatic events. These symptoms fall into three general categories: reliving, avoiding and increased arousal.
‘Reliving’ refers to the frequent re-experiencing of the event, typically through flashbacks, nightmares and hallucinations. There may also be an intense response to any reminder of the original event, such as the anniversary. ‘Avoiding’ refers to a number of behaviors aimed at avoiding the memory of the initial trauma and the associated strong feelings. This may include avoiding specific people, places and situations reminiscent of the trauma, leading to feelings of detachment and isolation. ‘Increased arousal’ refers to excessive anxiety and emotion, resulting in nervousness, difficulty sleeping, and angry outbursts. Physiological responses such as increased pulse and blood pressure are also common.
The physiology of PTSD
Human beings, like all animals, demonstrate a ‘fight or flight’ response when faced with a threatening situation. This immediate stress response involves the release of hormones such as adrenaline, which cause a number of physiological responses including increased heart rate and increased blood flow to the muscles, preparing the body to meet the perceived threat.
In the setting of severe trauma, a small structure in the brain called the amygdala may be responsible for linking the emotional memory of the event to a hyperactive fear response, a process known as fear conditioning. This hyperactive response allows nonthreatening reminders of the original traumatic event, like a flashback or the sight of a particular place, to unleash the full fear response elicited by the original trauma.
Current therapies for PTSD
The current strategy for the treatment of PTSD includes two major components, psychotherapy and medication. Psychotherapy refers to specialized counseling designed to reduce the severity of PTSD symptoms. This includes exposure therapy, which involves reliving the experience in a safe, controlled environment. Over time, this helps individuals confront their fear and develop coping strategies for dealing with stressful situations. Another strategy, cognitive behavioral therapy, teaches individuals to recognize and change dysfunctional thought patterns that lead to anxiety.
The mainstay in drug therapy for PTSD is antidepressants, particularly SSRIs (selective serotonin uptake inhibitors) including fluoxetine (prozac) and sertraline (zoloft). These drugs increase the level of serotonin, a neurotransmitter (chemical messenger) in the brain. Research has shown that individuals with PTSD have a low level of a subtype of serotonin, serotonin 1B.
Common blood pressure drug holds promise for PTSD
Scientists in the US have been studying civilian (nonmilitary) PTSD with the Grady Trauma Project. This project follows low income residents of Atlanta, Georgia who have high rates of PTSD related to widespread exposure to violence and physical and sexual abuse. Many individuals with PTSD within this group were also taking drugs called ACE (angiotension converting enzyme) inhibitors, generally prescribed for blood pressure control. Those patients taking ACE inhibitors had a 30 percent decrease in PTSD symptoms, while individuals taking other blood pressure drugs saw no effect. In particular, ACE inhibitors appear to decrease hyperarousal and nervousness.
ACE inhibitors interfere with a hormone called angiotensin II, known to control blood pressure. Preliminary research suggests that ACE inhibitors may decrease the symptoms of PTSD both by blocking physiological responses to stress such as increased blood pressure and by decreasing the brain’s response to stress in crucial areas such as the amygdala. Since this is the first time angiotensin has been linked to PTSD, this opens up an important new avenue for research both into the causes and treatment of PTSD. This is a benefit those suffering from PTSD may feel sooner rather than later; unlike brand new drugs that have to undergo a lengthy trial period, ACE inhibitors have been safely prescribed for hypertension for years. This could give doctors an exciting new way to treat PTSD relatively soon.