Post-Traumatic Stress Disorder (PTSD) is a debilitating mental health disorder that can occur in individuals who have experienced or witnessed a traumatic event. While the symptoms of PTSD are well documented, the underlying biochemistry of the disorder is less understood. In this article, we will explore the current understanding of the biochemistry of PTSD and how it may inform future treatments.
The Neurobiology of PTSD
The neurobiology of PTSD is complex and involves a number of different systems in the brain. The amygdala, hippocampus, and prefrontal cortex are three key areas that have been implicated in the development and maintenance of PTSD symptoms.
The amygdala is responsible for the processing of emotional stimuli and is thought to play a central role in the development of fear and anxiety responses. In individuals with PTSD, the amygdala appears to be overactive, leading to an exaggerated fear response to stimuli that are not actually threatening.
The hippocampus is involved in the formation of memories, particularly memories related to spatial and contextual information. In individuals with PTSD, the hippocampus appears to be smaller in volume, potentially leading to difficulties in processing and integrating traumatic memories.
The prefrontal cortex is responsible for higher-order cognitive processes such as decision-making and emotion regulation. In individuals with PTSD, the prefrontal cortex appears to be less active, potentially contributing to difficulties in regulating emotional responses to trauma-related stimuli.
Neurotransmitters and PTSD
In addition to structural changes in the brain, the neurotransmitter systems involved in regulating mood and anxiety are also thought to play a role in the development of PTSD. The neurotransmitters serotonin, dopamine, and norepinephrine have all been implicated in PTSD.
Serotonin is a neurotransmitter that regulates mood and is often targeted by antidepressant medications. Studies have shown that individuals with PTSD have lower levels of serotonin compared to healthy controls.
Dopamine is a neurotransmitter that is involved in reward processing and motivation. Studies have shown that individuals with PTSD may have altered dopamine function, potentially contributing to symptoms such as anhedonia.
Norepinephrine is a neurotransmitter that is involved in the stress response. Studies have shown that individuals with PTSD have higher levels of norepinephrine compared to healthy controls.
Cognitive Behavioral Therapy (CBT)
Cognitive Behavioral Therapy (CBT) is a form of psychotherapy that focuses on changing negative thoughts and behaviors. CBT has been shown to be effective in the treatment of PTSD (1). CBT for PTSD typically involves exposure therapy, in which the individual is gradually exposed to the traumatic event and learns to cope with their emotions in a safe environment.
Eye Movement Desensitization and Reprocessing (EMDR)
Eye Movement Desensitization and Reprocessing (EMDR) is a therapy that involves using eye movements to help process traumatic memories. EMDR has been shown to be effective in the treatment of PTSD. The exact mechanism of action of EMDR is not yet fully understood, but it is thought to help reduce the emotional intensity of traumatic memories.
Pharmacotherapy involves the use of medications to treat PTSD symptoms. Antidepressants such as selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) have been shown to be effective in the treatment of PTSD. Other medications, such as antipsychotics and anticonvulsants, may also be used to treat specific symptoms of PTSD, such as hyperarousal or nightmares.
Complementary and Alternative Medicine (CAM)
Complementary and Alternative Medicine (CAM) refers to therapies and practices that are not typically part of conventional medical treatment. CAM therapies that have been shown to be effective in the treatment of PTSD include yoga, meditation, and acupuncture. While the exact mechanism of action of these therapies is not fully understood, they may help to reduce stress and promote relaxation.
While our understanding of the biochemistry of PTSD is still evolving, it is clear that multiple systems are involved in the disorder. As a result, future treatments may need to be multimodal and target multiple pathways simultaneously. For example, medications that target both serotonin and norepinephrine have shown promise in the treatment of PTSD. Additionally, therapies such as cognitive-behavioral therapy and exposure therapy may help to normalize activity in the amygdala and prefrontal cortex, respectively.
PTSD is a complex disorder that involves multiple systems in the brain. While our understanding of the biochemistry of the disorder is still evolving, it is clear that multiple neurotransmitter systems are involved in the development and maintenance of symptoms. Future treatments for PTSD may need to be multimodal and target multiple pathways simultaneously to effectively treat the disorder.
Koenen KC, Ratanatharathorn A, Ng L, McLaughlin KA, Bromet EJ, Stein DJ, et al. Posttraumatic stress disorder in the World Mental Health Surveys. Psychol Med. 2017;47(13):2260-74.
Shin LM, Rauch SL, Pitman RK. Amygdala, medial prefrontal cortex, and hippocampal function in PTSD. Ann N Y Acad Sci. 2006;1071:67-79.
Smith ME. Bilateral hippocampal volume
Bisson JI, Roberts NP, Andrew M, Cooper R, Lewis C. Psychological therapies for chronic post-traumatic stress disorder (PTSD) in adults. Cochrane Database Syst Rev. 2013;12:CD003388.
Cusack K, Jonas DE, Forneris CA, Wines C, Sonis J, Middleton JC, et al. Psychological treatments for adults with posttraumatic stress disorder: A systematic review and meta-analysis. Clin Psychol Rev. 2016;43:128-41.
Stein DJ, Ipser JC, Seedat S. Pharmacotherapy for post traumatic stress disorder (PTSD). Cochrane Database Syst Rev. 2006;1:CD002795.
Niles BL, Mori DL, Polizzi C, Pless Kaiser A, Weinstein ES. A systematic review of randomized trials of mind-body interventions for PTSD. J Clin Psychol. 2018;74(9):1485-5