Background: Evaluations of clinical depression are traditionally based on verbal information. Nonverbal expressive behavior, however, being associated with a person's reflexive responses, may reveal negative emotional or social processes that are not under complete control of the patients. However, investigations of nonverbal behavior in the evaluation of depressed patients are still scarce. This study examines the nonverbal behaviors of a group of Brazilian patients, associating their nonverbal behavior with severity of depression. Methods: Forty depressed patients were evaluated at baseline (TO) and after a two-week transcranial direct current stimulation treatment (T1), according to rating scales and through a 21-category Ethogram for assessment of the frequency of nonverbal behaviors displayed during an interview. Results: Behaviors that were related to negative feelings and social disinterest decreased with corresponding clinical improvement and were associated with increased severity of symptoms at TO and greater negative affect and dissatisfaction at T1. Pro-social behaviors were associated with milder symptoms at TO and increased after treatment Facial, head and hand expressive movements stood out as important indicators because of their associations with severity of depression. Limitations: Duration of behaviors was not assessed and there was not a healthy control group with which to compare the findings. Conclusions: These results support the usefulness of nonverbal behavior as an evaluation technique in the assessment of clinical depression. (C) 2013 Elsevier B.V. All rights reserved.