Lyme disease (LD) caused by the spirochete Borrelia burgdorferi (Bb) results from human contact with rural environments and is transmitted by infected ticks (Ixodes spp.)

To report a case with LD and to highlight the importance of differential diagnosis in a first psychotic episode.

Case report and systematic review of the literature.

We report a case of a 19-year-old man that was admitted because of strange behaviour with alienation, perplexity and persecutory delusions. He had one previous admission to an inpatient unit two years prior and was diagnosed with psychosis not otherwise specified. After being admitted to the psychiatric ward a medical work up was completed. The patient had had a long stay in a rural environment; so anti-body specific to Bb was ordered and came positive. LD was diagnosed based on cerebral magnetic resonance imaging (MRI) findings and the presence of Bb in the cerebrospinal fluid. During treatment with anti-psychotic and antibiotic there was a noticeable clinical amelioration correlated with improvement of MRI's perfusion patterns.

LD is relatively rare, but physicians need to be aware of typical neuropsychiatric symptoms, given that they may occur months to years after the initial infection. Prompt diagnosis and effective treatment are crucial to avoid the possibly irreversible mental illness. In the evaluation of a first psychotic episode LD should be considered and excluded, principally if there's an epidemiological context and no psychiatric family history. MRI may be another useful asset in the diagnostic evaluation of this condition.

The authors have not supplied their declaration of competing interest.