Adolescents frequently describe stomach pain, headaches and nausea before they describe worry. The physical complaint is often the same process, expressed in the part of the body that noticed it.
The stress response is physical by design
Perceived threat activates systems that prepare the body to act: heart rate rises, breathing changes, muscles tense and digestion is deprioritized because it is not useful in an emergency.
That last effect produces genuine sensation. Nausea, cramping and appetite change are not imagined, and they occur whether the threat is physical or a presentation in third period.
So a student reporting a stomachache before school is describing something real. The question is what triggered the response, not whether the sensation is authentic.
Adolescents describe bodies more readily than feelings
Naming an internal emotional state requires vocabulary and a judgment that the listener will receive it well. Reporting pain requires neither and is more likely to produce help.
Physical complaints also carry less social cost. A stomachache is a legitimate reason to leave a room; feeling overwhelmed is treated by many students as an admission.
Girls in particular learn early that emotional expression is read as excessive, which makes the physical route to the same request quieter and safer.
Avoidance is what makes the pattern grow
Leaving the anxiety-provoking situation reduces the symptoms immediately, and that relief is a powerful reinforcement of the departure.
Each repetition strengthens the association, so the same trigger produces symptoms more readily the next time. The pattern is maintained by relief rather than by the original trigger.
This is why interventions typically work toward graded return rather than removal, though what that looks like for a particular student is a clinical judgment.
Physical causes must still be excluded
A stress explanation is not a diagnosis and must not be assumed. Persistent, worsening or unexplained symptoms require medical evaluation before anything is attributed to anxiety.
Weight loss, fever, night waking with pain, vomiting or symptoms present during vacations and weekends all point away from a purely situational pattern.
Only a clinician can make that determination, and the appropriate response to a repeated complaint is an appointment rather than an interpretation.
What the pattern reveals if anyone records it
Timing carries most of the information: whether symptoms cluster before particular classes, on particular days, or disappear entirely during school breaks.
Nobody sees that unless someone writes it down, and the person best placed to notice is often a parent tracking dates rather than reacting to each morning separately.