title: Peritraumatic tonic immobility in a large representative sample of the general population: association with posttraumatic stress disorder and female gender.
abstract: BACKGROUND
  Tonic immobility is an involuntary response to inescapable life-threatening events. Peritraumatic tonic immobility has been reported in convenience samples of female victims of sexual assault and in mixed-gender victims of different types of trauma. This study evaluated peritraumatic tonic immobility in a representative general population sample and its association with posttraumatic stress disorder (PTSD) and gender.
  
  
  METHODS
  3231 victims of traumatic events aged 15-75 years responded to the Tonic Immobility Scale. PTSD and traumatic events were assessed using the Composite International Diagnostic Interview (CIDI 2.1). We calculated the means and the standard deviations of Tonic Immobility Scale scores stratified by PTSD and gender. The association between tonic immobility scores and gender was explored controlling for potential confounders through a multiple linear regression model.
  
  
  RESULTS
  Tonic immobility scores were more than double in those who met criteria for PTSD and were almost four points higher in women. Gender differences remained statistically significant even after adjustment for confounding variables.
  
  
  CONCLUSIONS
  The cross-sectional and retrospective design may have given rise to recall bias. Results presented here may not apply to small and medium rural areas and the CIDI 2.1 can lead to a certain degree of misclassification.
  
  
  CONCLUSIONS
  We have expanded the scope of previous investigations on peritraumatic tonic immobility which were based on convenience samples only, showing its occurrence in victims of traumatic events using a large representative sample of the general population. Furthermore, we confirmed in an unbiased sample the association between peritraumatic tonic immobility and PTSD and female gender.
authors.affiliation: Institute of Psychiatry, Universidade Federal do Rio de Janeiro (IPUB-UFRJ), Rio de Janeiro, RJ, Brazil. Electronic address: juliana.kalaf@ipub.ufrj.br.
authors.forename: Juliana
authors.initials: J
authors.lastname: Kalaf
authors.affiliation: Institute of Psychiatry, Universidade Federal do Rio de Janeiro (IPUB-UFRJ), Rio de Janeiro, RJ, Brazil.
authors.forename: Liliane Maria Pereira
authors.initials: LM
authors.lastname: Vilete
authors.affiliation: Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (IBCCF-UFRJ), Rio de Janeiro, RJ, Brazil.
authors.forename: Eliane
authors.initials: E
authors.lastname: Volchan
authors.affiliation: Institute of Psychiatry, Universidade Federal do Rio de Janeiro (IPUB-UFRJ), Rio de Janeiro, RJ, Brazil.
authors.forename: Adriana
authors.initials: A
authors.lastname: Fiszman
authors.affiliation: Department of Epidemiology, Escola Nacional de Saúde Pública (ENSP-FIOCRUZ), Rio de Janeiro, RJ, Brazil.
authors.forename: Evandro Silva Freire
authors.initials: ES
authors.lastname: Coutinho
authors.affiliation: Department of Psychiatry, Universidade Federal de São Paulo, SP, Brazil.
authors.forename: Sergio Baxter
authors.initials: SB
authors.lastname: Andreoli
authors.affiliation: Department of Psychiatry, Universidade Federal de São Paulo, SP, Brazil.
authors.forename: Maria Inês
authors.initials: MI
authors.lastname: Quintana
authors.affiliation: Department of Psychiatry, Universidade Federal de São Paulo, SP, Brazil.
authors.forename: Jair
authors.initials: J
authors.lastname: de Jesus Mari
authors.affiliation: Institute of Psychiatry, Universidade Federal do Rio de Janeiro (IPUB-UFRJ), Rio de Janeiro, RJ, Brazil.
authors.forename: Ivan
authors.initials: I
authors.lastname: Figueira
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D046353:Immobility Response, Tonic; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012727:Sex Characteristics; D013313:Stress Disorders, Post-Traumatic / Q000150:complications / Q000523:psychology*; D014947:Wounds and Injuries / Q000150:complications / Q000523:psychology*; D055815:Young Adult