New insights challenge traditional diagnoses in adolescents with postural orthostatic tachycardia and behavioural changes

Clinicians are urged to broaden diagnostic evaluations in adolescents showing a sudden shift in behaviour, postural orthostatic tachycardia syndrome, and neuropsychiatric symptoms, recognising potential overlaps with Lyme disease, PANS, and other systemic conditions.

An adolescent who develops postural orthostatic tachycardia syndrome, obsessive-compulsive symptoms and a marked change in behaviour can present a diagnostic puzzle that should not be narrowed too quickly to a single label. Daniel Cameron, a Lyme disease clinician, argues that the key question is not whether Lyme disease explains every symptom, but whether the timing, clustering and severity of the changes suggest a broader medical process that still needs to be traced.

That matters because families often notice a clear break from a young person’s usual baseline. A previously outgoing teenager may become withdrawn, rigid or fearful; school performance may slide; sleep, eating and mood may change; and ordinary routines can give way to repeated checking, reassurance-seeking or distress around leaving home. Johns Hopkins researchers have reported that autonomic symptoms, including POTS, can appear in some patients with post-treatment Lyme disease, which supports the idea that orthostatic intolerance may be part of a wider syndrome rather than an isolated complaint.

POTS itself can be disabling enough to alter behaviour. A rapid rise in heart rate on standing can bring dizziness, fatigue, palpitations, brain fog and exercise intolerance, leaving adolescents unable to take part in sport, attend school consistently or maintain normal social activity. But as Cameron notes, that does not explain everything. Sudden obsessive-compulsive symptoms or abrupt personality change should prompt clinicians to consider whether another process is also at work, particularly if the onset follows an apparent infection or comes with other neurological or systemic features.

The overlap with paediatric acute-onset neuropsychiatric syndrome, or PANS, further complicates the picture. Research published on PANS describes a dramatic onset of obsessive-compulsive symptoms or severe food restriction, accompanied by additional acute neuropsychiatric changes. Lyme disease is among the infections that some clinicians consider as a possible trigger, although neither PANS nor OCD on its own proves Lyme disease is present. A 2018 study cited on PubMed also found clinically significant obsessive-compulsive symptoms in many adults with Lyme disease, but the relationship remains uncertain.

Cameron’s broader point is that clinicians should resist forcing all symptoms into one diagnosis. Depending on the case, evaluation may need to include Lyme disease, other tick-borne infections, autoimmune or inflammatory illness, thyroid disease, iron deficiency, sleep disorders, medication effects, migraines, epilepsy, dysautonomia and primary psychiatric conditions. The British-style clinical caution is simple: a psychiatric diagnosis or a POTS diagnosis should guide care, but it should not close the search for why a once-functioning adolescent changed so abruptly.