Transtorno psicótico agudo e transitório is characterised by acute onset of psychotic symptoms that emerge sem a prodrome and reach their maximal severity within two weeks. Symptoms may include delusions, hallucinations, disorganisation of thought processes, perplexity or confusion, and disturbances of affect and mood. Catatonia-like psychomotor disturbances may be present. Symptoms typically change rapidly, both in nature and intensity, from day to day, or even within a single day. The duration of the episódio does not exceed 3 months, and most commonly lasts from a few days to 1 month. The symptoms are not a manifestation of another medical condition (e.g. a brain tumour) and are not due to the effect of a substance or medication on the central nervous system (e.g. corticosteroids), including abstinência (e.g. alcohol abstinência).