Is the PHQ-9 valid for screening depression after a concussion?

Yes — the PHQ-9 is commonly used and has been studied in TBI populations, though its somatic items overlap with concussion symptoms and should be interpreted with that overlap in mind, particularly early in recovery.

How soon after a TBI should depression screening start?

Most protocols incorporate it at the first follow-up visit, commonly around one week post-injury, and repeat it at subsequent visits, especially if symptoms persist beyond the expected recovery window.

Does a high PHQ-9 score always mean the patient is depressed?

Not necessarily. Somatic items (fatigue, sleep, concentration) can be elevated by the concussion itself. Weight affective items more heavily and track the score's trajectory over time rather than relying on a single result.

What should a clinician do if the suicidality item on the PHQ-9 is positive?

Follow up directly with the patient about self-harm and suicidal ideation regardless of the overall score, and treat it with the same clinical response as any other positive suicidality screen — this should not be handled as an automated flag alone.

When should a positive depression screen trigger a referral rather than continued monitoring?

When the score is moderate or higher and not improving alongside physical recovery, when item 9 is positive at any level, when there's a prior psychiatric history with clear exacerbation, or when mood symptoms appear to be driving delayed return-to-work, return-to-learn, or return-to-play progress.

How Should You Screen for Depression After Traumatic Brain Injury?

Screen for depression after TBI using the PHQ-9 at baseline follow-up and at any visit where symptoms persist, with a low threshold for patients who have a prior psychiatric history, prolonged recovery, or high acute symptom burden. Because somatic PHQ-9 items (fatigue, sleep, concentration) overlap with concussion symptoms, interpret elevated scores in context rather than at face value, and pair screening with a direct question about self-harm ideation whenever a screen is positive.

Why Depression Screening Belongs in Routine Concussion Follow-Up

Traumatic brain injury, including mild TBI, is a recognized risk factor for new-onset or exacerbated depression and anxiety. That risk appears more pronounced in adults and in patients whose physical symptoms persist beyond the typical recovery window. Treating mood symptoms as an incidental byproduct of concussion — something that will resolve on its own once headaches and dizziness improve — is a common gap in otherwise thorough concussion care. Guideline-consistent practice folds mental health screening into the same visit cadence used for physical and cognitive recovery tracking, rather than deferring it to a separate referral pathway triggered only after a patient volunteers mood complaints.

This matters operationally as much as clinically: patients rarely raise depression unprompted in a visit focused on headache, balance, or return-to-play status, and a missed mood disorder can be the single largest driver of a stalled recovery that otherwise looks physically resolved.

When to Screen

At the first follow-up visit (commonly around one week post-injury), as part of the standard symptom review — not only when the patient reports low mood.
At every subsequent visit for patients with persisting symptoms, particularly once the recovery timeline extends past the expected window (roughly two to four weeks for adults, up to four weeks or more for adolescents).
With a lower threshold to screen early and repeatedly in patients who have any of: a prior psychiatric history, a prior concussion history, high acute symptom burden, prominent dizziness or vestibular symptoms, or a slower-than-expected trajectory. These are the same risk factors associated with prolonged recovery generally, and they overlap substantially with risk for new or worsened depression.
Whenever a return-to-work, return-to-learn, or return-to-play decision is being made for a patient with an extended course — mood symptoms can masquerade as motivational or cognitive complaints and should be ruled out before attributing slow reintegration purely to physical recovery.

Which Instrument to Use

The PHQ-9 is the most widely validated depression screen in TBI populations and is the standard first-line tool in concussion follow-up. It is brief, self-administered, and maps directly to DSM-based depressive symptom criteria, which makes it useful both clinically and for documentation purposes.

The GAD-7 is commonly administered alongside the PHQ-9, since anxiety and depression frequently co-occur post-TBI and share overlapping risk factors. Screening for one without the other misses a meaningful share of affected patients.

For patients with a suspected trauma component to their injury — assault, motor vehicle collision, combat exposure — the PCL-5 adds a PTSD-specific screen that the PHQ-9 and GAD-7 do not capture.

The Somatic-Overlap Problem

The PHQ-9's known limitation in TBI populations is item overlap: questions about fatigue, sleep disturbance, poor concentration, and psychomotor slowing are core PHQ-9 items and are also core concussion symptoms. A patient with an uncomplicated but still-resolving concussion can score in the mild-to-moderate range on somatic items alone, without any true depressive affect.

Practical interpretation approach:

Weight the affective and cognitive-mood items (anhedonia, depressed mood, guilt/worthlessness, and the suicidality item) more heavily than the purely somatic items when the patient is still within an active symptom-recovery window.
Track the score's trajectory over successive visits rather than anchoring on a single elevated score. A somatic-driven elevation should track downward alongside physical symptom resolution; a persistently elevated or rising score — especially on affective items — is more concerning for a true mood disorder.
Do not let symptom overlap become a reason to skip the screen. Under-screening because "it's probably just the concussion" is a more common and more consequential error than over-interpreting a borderline score.

Always Ask About Self-Harm Directly

TBI populations, and patients with prolonged post-concussive symptoms in particular, carry elevated risk for suicidal ideation. Any positive PHQ-9 item 9 response — even a low score elsewhere — warrants a direct, explicit follow-up conversation about self-harm and suicidal thoughts, conducted by the clinician rather than left to the screening tool alone. This should never be treated as an automated flag to route around; it requires the same clinical judgment and safety-planning response as any other positive suicidality screen.

When to Refer

Route to psychology, psychiatry, or integrated behavioral health rather than managing a positive screen within primary or specialty concussion care alone when:

The PHQ-9 or GAD-7 score is moderate or higher and does not track downward with physical symptom improvement.
Item 9 (suicidal ideation) is positive at any severity.
The patient has a prior psychiatric history and the current presentation represents a clear exacerbation.
Mood or anxiety symptoms appear to be driving delayed return-to-work, return-to-learn, or return-to-play progress independent of physical or cognitive recovery.
There is diagnostic ambiguity between a primary mood disorder, an adjustment reaction to injury, and TBI-related cognitive-affective symptoms — a distinction better made through integrated psychological assessment than through a single screening instrument. See when to refer for neuropsych testing for the parallel decision framework on the cognitive side.

Behavioral health should function as a standing member of the concussion care team rather than an occasional referral destination — see multidisciplinary concussion care team roles for how this fits alongside vestibular PT, neuropsychology, and headache specialty care.

How Kavera Handles This

Every concussion patient in Kavera gets a PHQ-9 at the first visit and on schedule after it, with Item 9 flagged for same-day review. Depression after TBI is caught on the calendar, not when the patient brings it up. Self-Serve practices run this with their own staff. On Managed, Juliet Mott's team runs it and bills it under your credentials.