Prior Mental Health Problems May Increase Risk of PTSD, MDD Following mTBI

Certain patients who experience mild traumatic brain injury (mTBI) may be at especially increased risk for developing posttraumatic stress disorder (PTSD) or major depressive disorder (MDD) following injury, according to a study published this week in JAMA Psychiatry.

“We observed that having an antecedent mental health problem prior to TBI [traumatic brain injury] was an exceptionally strong risk factor for having PTSD or MDD postinjury,” wrote author Murray B. Stein, M.D., M.P.H., of the University of California, San Diego and colleagues. “[T]his finding underscores the importance of clinicians being aware of the mental health history of their patients with mTBI, as this information is central to expectations regarding both short-term and long-term outcome.”

For this large, multisite study, Stein and colleagues included some 1,200 civilian patients whose head injury occurred within 24 hours of emergency department admission, who received a CT scan, and who scored 13 to 15 on the Glascow Coma Scale. About 20% of these patients reported having a psychiatric history (patients with what the authors referred to as “major debilitating mental disorders—for example, schizophrenia, bipolar disorder”—were excluded from the trial). Patients took the PTSD Checklist for DSM-5 (PCL-5) and the Patient Health Questionnaire-9 (PHQ-9) at the start of the trial and again at two weeks and three, six, and 12 months postinjury. The researchers also included a comparison group of 230 patients who experienced orthopedic trauma, but not head injury; six months of follow-up data on this group was included in the analysis.

Nearly 1 in 5 participants with mTBI had probable PTSD (19%) six months postinjury, compared with 8% of those with orthopedic injuries. Major risk factors for PTSD at six months after an mTBI included being black, having an mTBI caused by assault or violence, or history of psychiatric disorder—each of which was associated with a four to five times greater risk of PTSD.

About 9% of those with mTBI had probable MDD six months postinjury, compared with 3% of those with orthopedic injuries. Major risk factors for MDD at six months after an mTBI included being black and having a history of psychiatric disorder—each of which was associated with a three to four times greater risk of moderately severe to severe depression.

Stein and colleagues noted that they were uncertain how to characterize the finding that black patients were at increased risk for PTSD and MDD following a mTBI, but wrote that it did not appear to be due to the cause of injury or socioeconomic status, such as education, employment status, or health insurance status. They called for further study of this finding.

“Some individuals, on the basis of antecedent mental health status and—in the case of PTSD—context of injury (i.e., assault or other violence), are at substantially increased risk of mental health problems following mTBI,” Stein and colleagues concluded. “These findings should influence recognition of at-risk individuals following mTBI and inform efforts at surveillance and intervention.”

For related information, see the Psychiatric News article “Sertraline May Help Prevent Depression Following Traumatic Brain Injury.”

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Researchers Propose Rethinking Fear May Advance Treatment of Anxiety Disorders

A new neuroanatomical model for understanding fear and anxiety could have implications for how drugs are tested for anxiety disorders and could lead to new treatments, Joseph LeDoux, Ph.D., and Daniel Pine, M.D., wrote in a recent article in AJP in Advance.

While the physiological and behavioral responses to an imminent threat that comprise the `fight-or-flight’ phenomenon are regulated by subcortical neural networks centered on the amygdala, LeDoux and Pine propose that the subjective experience of fear is regulated by higher order cortical networks responsible for cognitive processes such as attention and working memory.

This new model would replace the long-accepted “fear circuit” model, in which both physiological reactions and the subjective experience of fear are regulated by one circuit centered on the amygdala. LeDoux and Pine make the same distinction for anxiety and other emotions—different circuits underlie the conscious feelings of these emotions and those that underlie the behavioral and physiological responses that occur in tandem.

If LeDoux and Pine are correct it suggests that animal models used to test medications for treating anxiety disorders—founded on the more traditional unitary fear circuit theory—may not adequately capture the subjective experience of fear and anxiety as felt by humans.

“This is a really important paper,” Murray Stein, M.D., vice chair for clinical research in the Department of Psychiatry at the University of California, San Diego, told Psychiatric News. “[L]eDoux and Pine suggest we have been going down the wrong path ... because what we are modeling in animals isn’t what we are measuring, assessing, and trying to treat in humans.”

“Animal research is important and useful, especially if we know how to use it,” LeDoux said. “Our ability to understand the brain is only as good is our understanding of the psychological processes involved. If we have misunderstood what fear and anxiety are, it is not surprising that efforts to use research based on this misunderstanding to treat problems with fear and anxiety would have produced disappointing results.”

For related information, see the Psychiatric News article “Humans, Rodents Pay Close Attention to Fear, Anxiety Expressed by Parents.”

(Image: andreiuc88/Shutterstock)