Post-Traumatic Stress Disorder

How Do We Diagnose PTSD?

Brain scans help us understand the PTSD brain, but not diagnose PTSD.

Posted Apr 15, 2019

Celebrities and public figures have recently been more open about mental health conditions they deal with. This is a positive sign of vanishing stigma of mental illness and is also helps in reducing it. The most recent in this line was Ariana Grande’s mention of Posttraumatic Stress Disorder (PTSD). And a brain scan. 

I am a psychiatrist and neuroscientist specialized in the research, diagnosis, and treatment of PTSD, and I see this as an opportunity to discuss PTSD, how it is diagnosed, and its treatments.

What Is Posttraumatic Stress Disorder?

PTSD is a clinical condition, and a consequence of exposure to extreme traumatic experiences such as motor vehicle accidents, assault, robbery, rape, combat, torture; situations that are threatening to the integrity of the person. Trauma may happen to the person or be witnessed happening to others. As a result, the brain switches to “survival mode”, doing its best to avoid another exposure to such experiences. The person is always anxious and hyper-vigilant, and constantly screens for danger. This leads to avoidance of any situation, cue, or memory that can be relevant or reminders of the traumatic experience. The person also experiences repetitive nightmares, flashbacks (as if the trauma is happening in here and now, experiencing the visions, voices, smells, and the touch), and intrusive memories. PTSD is very often comorbid with depression, and a high level of anxiety.

PTSD is very common, affecting 8 percent of the US population, up to 30% of the combat-exposed veteran, and 30-80 percent of refugees and victims of torture.

What are brain scans?

A “brain scan” is a general term that covers a diverse group of methods of imaging the brain. In psychiatric clinical practice, brain scans are mostly used to rule out visible brain lesions that may be causing psychiatric symptoms. However, in research, we use them to learn about the pathologies of the brain in mental illness. A common method is magnetic resonance imaging (MRI) that allows us to look at the changes in the volume, structure of different areas of the brain and integrity of the pathways connecting them.  Functional MRI (fMRI) examines blood flow in different areas of the brain as a measure of their dynamic function mostly in response to a task or event (thinking about trauma, or view of a trauma-related image). I use fMRI in my research, to look at the brain circuitry involved in how people can be instructed to learn fear and safety. Positron emission tomography (PET), Single Photon Emission CT (SPECT) are also used in looking at brain function. 

At the current stage of the technology and research, we only use these methods for researching the brain changes in mental illness, and NOT making diagnoses. In other words, we have to combine data from tens of people with a mental illness, to determine how on average, different areas of their brain may differ in volume or function from others.

How do we diagnose PTSD?

Like most other psychiatric conditions, PTSD is a clinical diagnosis. That means we diagnose PTSD by the symptoms presented by the patient. Clinicians look for a constellation of symptoms for a diagnosis: 1) History of exposure to trauma; 2) Intrusive symptoms such as frequent flashbacks, nightmares, intrusive memories; 3) avoiding any reminder of trauma (e.g. veteran avoiding watching Saving Private Ryan), and its memories; 4) hyperarousal (e.g. hypervigilance, sleep disturbances, being easily startled); 5) negative emotions and affect; and 6) significant distress or dysfunction. When enough number of the above criteria is met, a diagnosis of PTSD is made. 

We use the above criteria for mostly consistency in research, as we want to be sure that across different studies, what we call PTSD, passes the certain severity, and diversity of symptoms threshold. However, the effects of trauma may not reach the “diagnostic threshold” for PTSD, but can still be very stressing. A traumatized person who has frequent nightmares and flashbacks, and avoids leaving their house out of fear, is seriously stressed even though they may not meet the required number of “negative symptoms” per diagnostic manual. From a clinical perspective, we still address their symptoms and treat them. In other words, what matters in clinical practice, is helping with the symptoms that are distressing and cause dysfunction.

What do brain scans tell us about PTSD?

Although we do NOT use brain scans to diagnose PTSD in the clinic, we use them to understand what happens in the PTSD brain. There is abundant evidence for changes in the structure and function of different areas of the brain involved in fear response and anxiety, regulation of emotions, cognitive processing, and memory. For example, there is consistent evidence for reduced volume in the hippocampus (involved in memory and context processing), leading to difficulties differentiating cues that resemble trauma (slamming door) from the trauma cue itself (gunshot). Abnormalities of the hippocampus also lead to impairments of differentiating the safe context from the context in which trauma happened (fear response to a road kill in Ann Arbor, which may resemble an IED in Iraq). We also know from fMRI research, that the amygdala (involved in fear response), has larger activity in response to viewing or memory of trauma reminders, or viewing of negative facial affect. These findings are possible in studies of averaging across brain scans of many people, and not useful in one-person diagnosis. 

To summarize, brain imaging is an extremely useful tool in understanding the aberrations in the structure and function of a PTSD brain but does not diagnose the condition.

How do we treat PTSD?

We have effective treatments for PTSD. Treatment mostly involves psychotherapy and medications. Psychotherapy helps to detach traumatic memories from the severe emotional response, changing the thoughts that lead to distress and avoidance, and helping the person get back to adaptive ways of coping with life. There is evidence that talk therapy can help reverse negative changes in brain function and structure. Our team has been using body-based mindful methods of yoga and dance therapies for helping traumatized refugees, showing positive effects. We need more evidence from larger groups to comfortably offer these methods as established treatment.

Medications mostly include antidepressants, and help in reducing the high level of emotional arousal, allowing the person to more effectively use their cognitive and rational brain in dealing with stressful conditions. Benzodiazepines, including Xanax, are NOT recommended for treating PTSD.

Finally, lifestyle changes and physical activity are as important in addressing PTSD and other fear and anxiety related disorders. I have detailed these helpful life changes here.

This also appears in The Conversation.