Measuring depression and anxiety in autistic college students: A psychometric evaluation of the PHQ-9 and GAD-7.
The PHQ-9 suicide item is biased in autistic students—add a second screener for accurate risk checks.
01Research in Context
What this study did
Mackenzie et al. (2024) asked if the PHQ-9 and GAD-7 work the same way for autistic and neurotypical college students. They gave both groups the two short checklists and ran math tests to see if each question measures the same trait in both groups.
The goal was to find out if we can trust score differences between autistic and non-autistic students.
What they found
Most questions behaved the same, but the PHQ-9 suicide item did not. Autistic students answer that item differently, so equal scores do not mean equal suicide risk.
The GAD-7 held up well for anxiety. The PHQ-9 works for depression severity, yet the suicide item needs backup probes.
How this fits with other research
Hedley et al. (2023) extends this finding. After learning the PHQ-9 suicide item is biased, they built the SIDAS-M, an autism-friendly suicide screener for verbal adults. Use SIDAS-M when you need a clear risk picture.
Garwood et al. (2021) is a predecessor that used the same scales. Their 2021 survey showed autistic students already scored higher on both tools. Mackenzie now tells us those higher scores are mostly real, except for the suicide item.
Davidovitch et al. (2018) warned us in a systematic review that generic mental-health tools might misread autistic adults. Mackenzie’s 2024 data confirm that warning for the PHQ-9 suicide question.
Why it matters
You can keep using the PHQ-9 and GAD-7 for autistic college clients, but always add a second suicide question. A simple follow-up like "Tell me more about those thoughts" catches risk the PHQ-9 item can miss. Update intake packets now: pair the PHQ-9 with SIDAS-M or a brief clinical probe.
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Add one follow-up question after the PHQ-9 item 9, such as "Are you thinking of acting on those thoughts?" and document the answer.
02At a glance
03Original abstract
Anxiety, depression, and suicidality are major concerns among college students, though less is known about these constructs in autistic college students. Given the rising number of autistic individuals entering college, adequate screening and diagnosis of mental health difficulties is necessary to provide care to this population. For example, despite widespread usage of the Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7), it is unknown if the two instruments accurately measure depression and anxiety the same way between non-autistic and autistic individuals. Thus, the current study was the first to examine how these instruments measure depression and anxiety symptoms in autistic versus non-autistic college students. Utilizing tests of construct measurement in a sample of autistic (n = 477) and non-autistic (n = 429) university students aged 18-29, results showed that while the GAD-7 and PHQ-9 appear to be accurately capturing anxiety and depression in autistic college students, the PHQ-9 item assessing suicidality was found to be measuring different things. This indicates that autistic college students are not interpreting this question the way non-autistic students are, and thus, the measure is failing to capture suicidality in autistic people. Future investigators should continue to assess the appropriateness of using common screening measures, originally created by non-autistic people, in autistic populations.
Autism : the international journal of research and practice, 2024 · doi:10.1177/13623613241240183