PTSD: National Center for PTSD

Co-occurring PTSD and Neurocognitive Disorder (NCD)

Matthew Yoder, PhD, and Sonya Norman, PhD

Research findings over the past decade have shown a connection between posttraumatic stress disorder (PTSD) and neurocognitive disorders (NCD) among older adults and survivors of traumatic brain injuries. However, we do not have sufficient longitudinal data to fully understand the pathways through which PTSD and NCD alter one another's risk and expression.

NCD and Dementia

NCD refers to the group of disorders in which the primary clinical concern is acquired cognitive impairment rather than developmental cognitive impairment. With the release of DSM-5, the term "dementia" has been subsumed by the classification NCD (1). It is noted in DSM-5 that "dementia" may be retained for use in settings where the term is customary and understood by patients and clinicians. However, NCD is preferable, especially for conditions that affect younger individuals and are not degenerative (e.g., secondary impairment to traumatic brain injury or HIV). As cognitive deficit can occur in a number of domains (i.e., complex attention, executive function, learning and memory, language, perceptual-motor, and social cognition), the broader definition of NCD is also useful when decline occurs in a single domain, rendering the term "dementia" inaccurate (1).

Mild NCD Versus Major NCD

The diagnoses categorized as NCD exist on a continuum from mild to major cognitive and functional impairment. Decline at any level of the continuum can be acquired from a number of sources including traumatic brain injury (TBI), substance or medication use, HIV infection, Alzheimer's disease, or other brain diseases. Major NCD, regardless of the manner in which it was acquired, is characterized by significant cognitive decline relative to a previous level of functioning as well as high impairment in daily functioning. Mild NCD involves moderate cognitive deficits that do not interfere with basic daily functioning but is associated with greater effort or accommodation to maintain functioning (1).

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PTSD and NCD Co-occurrence

Bi-directional relationship between PTSD and NCD

The pathways through which PTSD and NCD affect each other are unclear. Most studies that assess risk for NCD among those with PTSD are cross-sectional, so while research shows that having PTSD makes acquiring a co-occurring NCD diagnosis more likely, a causal relationship has not been established. In a study of Veterans ages 55 and older enrolled in VA health care, those with PTSD were found between 1.77 and 2.31 times more likely to receive a first-time diagnosis of dementia over a seven year period than those without PTSD (2). Preliminary evidence also suggests that PTSD symptoms may be more severe in persons with dementia (3), cognitive impairment in general (4), and TBI (5), compared to samples without those conditions.

Possible risk factors for concurrent PTSD and NCD

One common shared risk factor for the development of PTSD and NCD is the presence of a mild traumatic brain injury (mTBI). Most research on TBI and PTSD suggests that experiencing mTBI places one at greater risk for PTSD and NCD. For example, among injured patients admitted to a trauma hospital, those who sustained a mild TBI were 1.92 times more likely to have PTSD than those injured without a mild TBI (6). Similarly, in a sample of soldiers three to four months after returning from deployment to Iraq, 43.9% who reported loss of consciousness met criteria for PTSD compared with 16.2% who sustained other physical injury and 9.1% who were not injured (7). While it is well established that as TBIs become more severe the risk of cognitive impairment also increases (8), several studies have suggested that PTSD is less likely to occur in the context of moderate and severe, compared to mild, TBI possibly due to the hypothesized protective nature of loss of consciousness during or directly following a traumatic event (9,10).

Substance use also may increase the risk for both NCDs and PTSD. A recent study found that Veterans with substance use disorder (SUD) who were residents of a VA residential nursing home had higher rates of PTSD, dementia, and physical problems compared to those without SUD (11).

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Conclusions

PTSD and NCD often co-occur and having one increases the risk of developing the other. The two conditions also share several risk factors including mTBI and SUD. While research has identified a connection between PTSD and NCD, the direction and specific nature of the relationship between them has not been established. For more information about assessment and treatment considerations, see Assessment and Treatment for PTSD with Co-occurring Neurocognitive Disorder (NCD).

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References

1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed). Washington, D.C.: Author.
2. Yaffe, K., Vittinghoff, E., Lindquist, K., Barnes, D., Covinsky, K. E., Neylan, T., Kluse, M. & Marmar, C. (2010). Posttraumatic stress disorder and risk of dementia among US Veterans. Archives of General Psychiatry, 67, 608-613. doi: 10.1001/archgenpsychiatry.2010.61
3. Hamilton, J. D., & Workman Jr., R. H. (1998). Persistence of combat-related posttraumatic stress symptoms for 75 years. Journal of Traumatic Stress, 11, 763-768. doi: 10.1023/A:1024449517730
4. Mittal, D., Torres, R., Abashidze, A., & Jimerson, N. (2001). Worsening of post-traumatic stress disorder symptoms with cognitive decline: Case series. Journal of Geriatric Psychiatry and Neurology, 14, 17-20. doi: 10.1177/089198870101400105
5. Vasterling, J. J., Braily, K., Procter, S. P., Kane, R., Heeren, T., & Franz, M. (2012). Neuropsychological outcomes of mild traumatic brain injury, post-traumatic stress disorder and depression in Iraq-deployed US Army soldiers. The British Journal of Psychiatry, 201, 186-192. doi: 10.1192/bjp.bp.111.096461
6. Bryant, R. A., O'Donnell, M. L., Creamer, M., McFarlane, A. C., Clark, C. R., & Silove, D. (2010). The psychiatric sequelae of traumatic injury. American Journal of Psychiatry, 167, 312-320. doi: 10.1176/appi.ajp.2009.09050617
7. Hoge, C. W., McGurk, D., Thomas, J. L., Cox, A. L., Engel, C. C., & Castro, C. A. (2008). Mild traumatic brain injury in U. S. soldiers returning from Iraq. The New England Journal of Medicine, 358, 453-463. doi: 10.1056/NEJMoa072972
8. Dikmen, S. S., Corrigan, J. D., Levin, H. S., Machamer, J., Stiers, W., & Weisskopf, M. G. (2009). Cognitive outcome following traumatic brain injury. Journal of Head Trauma Rehabilitation, 24, 430-438. doi: 10.1079/HTR.0b013e3181c133e9
9. Joseph, S., & Masterson, J. (1999). Posttraumatic stress disorder and traumatic brain injury: Are they mutually exclusive? Journal of Traumatic Stress, 12, 437-453. doi: 10.1023/A:1024762919372
10. Glaesser, J., Neuner, F., Lutgehetmann, R., Schmidt, R. & Elbert, T. (2004). Posttraumatic stress disorder in patients with traumatic brain injury. BMC Psychiatry, 4, 5. doi: 10.1186/1471-244X-4-5
11. Lemke, S., & Schaefer, J. A. (2010). VA nursing home residents with substance use disorders: Mental health comorbidities, functioning, and problem behaviors. Aging & Mental Health, 14, 593-602. doi: 10.1080/13607860903586169

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