Distúrbio vs. transtorno vs. perturbação
Didactically, these words are synonyms, but usage varies by region and context. In clinical settings, transtorno is the standard term in Brazil, while perturbação is standard in Portugal. Meanwhile, distúrbio is often associated with physiological malfunctions.
Distúrbio
C1This word is often used to describe a physiological malfunction or a biological problem within a specific system of the body. It suggests that a natural order or rhythm (like sleep or digestion) has been altered.
O paciente está tratando um distúrbio do sono que causa insônia.
(The patient is treating a sleep disorder that causes insomnia.)
Distúrbios hormonais podem afetar o humor e o peso.
(Hormonal disorders can affect mood and weight.)
Ela procurou ajuda para um distúrbio alimentar.
(She sought help for an eating disorder.)
O médico explicou que é um distúrbio metabólico leve.
(The doctor explained that it is a mild metabolic disorder.)
Transtorno
B2In Brazil, this is the official technical term used in psychiatry and psychology (equivalent to the DSM-5 usage of disorder). Outside of medicine, it implies a significant inconvenience, mess, or disruption to a routine.
O transtorno de ansiedade generalizada afeta muitas pessoas.
(Generalized anxiety disorder affects many people.)
Ele foi diagnosticado com transtorno obsessivo-compulsivo.
(He was diagnosed with obsessive-compulsive disorder.)
A obra na estrada causou um grande transtorno aos motoristas.
(The roadwork caused a major inconvenience to the drivers.)
Transtorno bipolar exige acompanhamento médico constante.
(Bipolar disorder requires constant medical monitoring.)
Perturbação
C1In European Portuguese (Portugal), this is the clinical standard for disorder (similar to transtorno in Brazil). In general usage, it refers to agitation, a breach of peace, or a temporary state of confusion.
Os vizinhos reclamaram da perturbação do sossego à noite.
(The neighbors complained about the disturbance of the peace at night.)
Em Portugal, o termo técnico é perturbação de stress pós-traumático.
(In Portugal, the technical term is post-traumatic stress disorder.)
Sinto uma leve perturbação visual quando olho para a luz.
(I feel a slight visual disturbance when I look at the light.)
Houve uma perturbação na ordem pública durante o protesto.
(There was a disturbance of public order during the protest.)
Summary
Use transtorno for mental health diagnoses in Brazil and for general inconveniences. Use perturbação for mental health diagnoses in Portugal or to mean disturbance (agitation/noise). Use distúrbio primarily for physical systems failing to function correctly (like sleep or metabolism).