Short questionnaires about mood and anxiety are now routine in American primary care and appear in apps and online quizzes. They are screening instruments, and screening is a specific thing.
Screening sorts, evaluation decides
A screening instrument identifies people who warrant a closer look, operating quickly and cheaply across a large population that mostly does not have the condition.
Diagnosis requires a clinical evaluation covering history, duration, functional impact and alternative explanations including medical conditions and medication effects.
The questionnaire is therefore the beginning of a process, and a score alone establishes nothing about what a person has.
Cutoffs are chosen, not discovered
Any threshold trades sensitivity against specificity, since lowering it catches more true cases while also flagging more people who do not have the condition.
Screening tools are typically set to favor sensitivity, on the reasoning that a missed case is worse than an unnecessary follow-up conversation.
This is why elevated scores are common in general populations and why an elevated score should be read as a prompt rather than a finding.
Symptoms overlap with ordinary circumstances
Items ask about sleep, energy, appetite, concentration and interest, all of which are affected by shift work, new parenthood, grief, illness and medication.
The instrument cannot distinguish those causes, which is a large part of why clinical evaluation exists and why context is asked about afterward.
Grief in particular can produce a high score while representing an expected response to loss rather than a condition requiring treatment.
Repeat measurement is the more useful application
These tools were designed partly to track change, and repeated administration during treatment shows direction in a way a single score cannot.
Measurement-based care uses that property, adjusting a treatment plan when scores fail to move rather than relying on impression alone.
Comparing a person's scores over time is defensible in a way that comparing one person's score to another's generally is not.
Online versions lose the surrounding process
A questionnaire administered in a clinic is followed by a conversation, which is where the interpretation and any next step actually occur.
The same items presented online return a result with no follow-up, and some are attached to services selling treatment based on the result.
A concerning score is a reason to speak with a licensed clinician, and thoughts of self-harm warrant contacting a crisis line or emergency services immediately.