Most of the people I work with inside my therapy practice have more than one mental health diagnosis. And this is not something specific to my clients; 75 percent of people with an anxiety disorder will also meet criteria for clinical depression at some point in their lives.
Take my client, Kay, for example. During our first session, I asked her about the symptoms she’d been experiencing and learned that she struggled with social anxiety disorder (SAD), bulimia nervosa (BN), and borderline personality disorder (BPD).
Despite the fact that most people show symptoms of more than one condition, most proven treatments have been developed and tested for a single diagnosis. That means the traditional way of helping someone like Kay would be to create a treatment plan that daisy-chained the separate therapy protocols for each individual disorder.
We might start with six months of dialectical behavior therapy to address her BPD, followed by another three months of cognitive-behavioral therapy (CBT) focused on her social anxiety and an additional three months of CBT for her eating disorder.
This year-long treatment plan is incredibly inefficient, and that’s assuming I even have expertise with each of these unique treatment protocols.
My frustrations as a clinician have informed the research I do as a professor. For the past 15 years, I’ve been trying to make treatment more potent and parsimonious for people like Kay. To do this, I’ve been developing and testing interventions that target personality-based risk factors for mental health conditions, instead of the disorders themselves.
What Kay’s Diagnoses Have in Common
When researchers look across separate diagnoses for shared risk factors, the same culprit keeps showing up: neuroticism. That’s the technical name for a personality trait many of us know intimately: the tendency to feel negative emotions strongly and often, and to interpret ambiguous situations as threatening. A landmark review by Benjamin Lahey (2009) showed that neuroticism predicts the onset of anxiety, depression, posttraumatic stress disorder (PTSD), and eating disorders better than almost any other single factor.
For Kay, the connection was easy to see once we named it. Her panic before a work presentation, her urge to binge after a stressful day, and the intensity of her response when a friend canceled plans all had different surface features but the same engine underneath. She was wired to feel emotions intensely and to do whatever she could to make those feelings stop, even when the strategies she reached for tended to backfire.
That insight reframes the treatment plan. If neuroticism is the shared root, then the question is no longer which protocol for which diagnosis. The question is how to work with the underlying trait that’s driving all of it.
Treating the Trait, Not Each Diagnosis
This question has shaped my research for the past two decades. With my mentor David Barlow at Boston University, I co-developed the Unified Protocol, a single CBT-based treatment that targets neuroticism directly. Across more than a dozen randomized trials, it produces meaningful reductions in anxiety, depression, PTSD, and related conditions in 12 to 16 weeks, regardless of the specific diagnosis someone walks in with.
My National Institute of Mental Health-funded team has since extended this approach to additional traits, including the emotional sensitivity that often shows up in people diagnosed with BPD. In our recent trials, an 18-week, trait-focused protocol delivered by generalist therapists produces outcomes on par with a full year of dialectical behavior therapy.
For Kay, that meant one shorter treatment instead of three back-to-back ones. We worked on how she related to her own emotions, building tolerance for distress, identifying the avoidance moves that kept the cycle going, and slowly shifting how reactive her nervous system was to ordinary triggers. Her symptoms across all three diagnoses softened in parallel.
Neuroticism Essential Reads
A Shorter, Wider Path Forward
Most people in mental health treatment have collected more than one label. The system tends to respond by stacking treatments on top of each other. The science suggests we can do better by going underneath them.
If you’ve been cycling through diagnoses and protocols, ask your therapist about the personality traits driving your symptoms, not just the symptoms themselves. The skills that help with one condition often help with the others, because at the trait level, they really are the same thing.