A case series involving two teenagers and a 20-year-old adds to growing, but still limited, evidence that PANDAS-like neuropsychiatric syndromes may emerge after puberty.
A newly published case series is adding to a small but growing body of evidence that PANDAS-like illnesses may not be confined strictly to childhood. According to a report in Clinical Case Reports, three patients aged 16 and 20 developed abrupt obsessive-compulsive symptoms, tics, abnormal movements and major behavioural change after throat illnesses, raising the question of whether similar post-infectious syndromes can first appear after puberty.
PANDAS, short for paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections, has traditionally been defined by sudden-onset OCD, tics or both in children, with symptom onset before puberty. A broader diagnosis, PANS, or paediatric acute-onset neuropsychiatric syndrome, does not require proof of streptococcal infection and can include abrupt OCD or restricted eating alongside other neuropsychiatric symptoms. That distinction matters when a teenager or young adult develops a sudden psychiatric or neurological illness after an infection but falls outside the original PANDAS age range.
The three cases described in the 2026 report were strikingly varied. One 16-year-old girl developed tics, obsessive-compulsive behaviour and urinary incontinence about a month after a throat infection, then deteriorated further with mutism and signs resembling catatonia. A 20-year-old man, who was her brother, later developed vocal tics, incontinence, severe food refusal, fearfulness and persecutory delusions after a febrile throat illness, losing about 10 kilograms. A third patient, a previously healthy 16-year-old boy, developed involuntary head movements, behavioural changes, hallucinations and mutism within days of sore throat and fever. Their responses to treatment were uneven, with some temporary improvement after intravenous immunoglobulin, plasma exchange or antibiotics, but none of the cases establishes a definitive cause.
The report also highlights how difficult it can be to pin down diagnosis and treatment. Routine brain imaging and cerebrospinal fluid testing were normal or only nonspecifically abnormal in parts of the series, showing that a normal MRI does not rule out a serious neuropsychiatric disorder. At the same time, the absence of a single confirmatory test means clinicians still have to weigh infectious evidence, symptom pattern and alternative explanations such as autoimmune encephalitis, psychiatric illness, metabolic disease or other neurological conditions. In one patient, Lyme disease was considered but not supported by confirmatory testing, underscoring that sudden psychiatric symptoms alone do not prove a tick-borne infection.
Earlier case reports have made similar points. Published reports in 2010, 2021, 2022, 2023 and 2024 described young adults with abrupt OCD, tics, psychosis or confusion following streptococcal infections, and some improved after immunomodulatory treatment such as plasmapheresis or rituximab. Even so, these accounts remain isolated and do not prove that classical PANDAS starts in adulthood. What they do suggest is that clinicians should take sudden OCD, tics, severe behavioural change, psychosis or food refusal seriously at any age, and move quickly to a broad medical evaluation rather than assuming the symptoms are purely psychiatric.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
