In the face of danger, our minds are supposed to sharpen. But what if, for many people, stress doesn’t heighten focus—it hijacks it?

A sweeping new review from Edith Cowan University offers a sobering update to the classic story of stress and the brain. Instead of simply preparing us for fight or flight, acute stress may cripple mental processes essential for emotional control—particularly in people already grappling with depression, anxiety, or borderline personality disorder.

A Breakdown in the Brain’s Control Center

The study, published in the Journal of Affective Disorders Reports, reviewed 17 international experiments examining how acute stress impacts what psychologists call “executive functions.” These include working memory (our ability to juggle information), response inhibition (resisting impulsive actions), and cognitive flexibility (adapting to change).

All three are crucial for managing our inner emotional world. “These executive functions are vital for controlling emotional responses, especially in challenging situations,” said Tee-Jay Scott, lead author of the study.

But when stress hits hard and fast, these mental abilities may falter—especially in those with mental health vulnerabilities. The researchers found that in people with symptoms of depression, working memory takes a hit. In those with borderline personality disorder, the ability to inhibit impulsive reactions seems to slip under stress.

These kinds of vulnerabilities are often identified with the aid of mental health assessments, which use standardized tools to evaluate emotional and cognitive functioning. But even when people don’t meet the clinical threshold for a diagnosis, their brains may still respond to stress in ways that disrupt daily life.

Why Common Therapies Sometimes Fall Short

Executive functions are the mental scaffolding that many therapies rely on. Cognitive behavioral therapy (CBT), for instance, teaches patients to challenge unhelpful thoughts and replace them with healthier ones, a process that demands planning, inhibition, and mental flexibility.

But if stress undercuts these cognitive tools in real time, it could help explain why many people with distress disorders don’t respond well to such treatments.

“Many psychological therapies are cognitively demanding,” said Professor Joanne Dickson, co-author of the study. “If acute stress is interfering with the mental processes that support emotion regulation, it could undermine a person’s ability to benefit from these treatments—especially during periods of heightened distress.”

Indeed, the team suggests this could be one reason why up to half of patients with generalized anxiety disorder or major depressive disorder show little or no improvement with standard talk therapies.

Rethinking Therapy: Timing, Tailoring, and Tolerance

Rather than throw out cognitive therapy, the researchers argue, clinicians should refine it. That might mean bolstering executive functions before diving into emotionally demanding sessions, or tailoring interventions based on how a person’s brain reacts to stress.

“It’s not just about what therapy is used, but when and how it’s delivered,” said Scott. “Therapy may need to be more flexible, or even paused during periods of high stress to preserve its effectiveness.”

One intriguing clue emerged from the review: even people with mild depressive symptoms—not enough to qualify for a formal diagnosis—showed signs of executive function impairment when stressed. That suggests the brain’s stress response exists on a continuum, not an on-off switch triggered by pathology.

The study also taps into a growing movement in psychiatry to move beyond traditional diagnostic categories. Instead of discrete “disorders,” researchers are focusing on dimensions of dysfunction—like emotional distress and cognitive control—that cut across many conditions.

In this case, the researchers used the Hierarchical Taxonomy of Psychopathology (HiTOP) model, which groups depression, anxiety, and borderline personality disorder under a shared umbrella of “distress disorders.” These conditions are often comorbid and share a core difficulty: altered stress reactivity.

Studies show that people with these disorders often have unusual stress hormone patterns, like blunted or exaggerated cortisol responses, and show reduced prefrontal brain activity during stress—a sign that their mental brakes may be failing just when they’re most needed.

Next Steps: Precision Mental Health

The findings open new avenues for research and treatment. Could simple cognitive exercises help buffer executive functions before a therapy session? Could stress resilience be trained like a muscle? Could biomarkers like cortisol or heart rate help determine the best moment to begin—or pause—therapy?

“Understanding how stress interacts with brain function is key to improving mental health outcomes,” Scott said.

For now, the message is clear: mental health is more than just mood or diagnosis. It’s also about timing, context, and the hidden fault lines in our mental architecture. And in a world that’s not getting any less stressful, knowing how stress reshapes our thinking might be the most important therapy of all.