Highlights

• Total or partial amnesia during a sexual assault is frequent (45.9% of our population)
• Amnesia is not associated with PTSD symptoms in women victims of sexual assault
• Amnesia during the assault is more frequent in younger women presenting with an alcohol or drug intoxication with an unknown alleged perpetrator

Sexual assault

Women sexual victimization is a major issue for society an Public health [1]. In Switzerland, almost one woman out of five (22%) has been a victim of sexual assault in the past, according to Amnesty International Switzerland [2]. Sexual assault can lead to severe and frequent psychological post-traumatic consequences [3-5]. Showed that in an American population sexual assaults and war combats were the traumatic events the most likely leading to psych traumatic symptoms. These consequences could be a characterized post-traumatic stress disorder (PTSD) or isolated PTSD symptoms such as anxiety, flashbacks, sleep problems, sadness and affect abrasion. Between 17 and 65% of sexual assault victims present with PTSD symptoms [3]. Some of them starting immediately after the assault. Amongst people suffering from PTSD in the US, sexual assault victims are one of the majority groups [6]. Usually, symptoms tend to diminish with time [7, 8].

The presence and intensity of immediate and post-immediate symptoms are predictors of a future development of a characterized PTSD [9, 10].

Amnesia

Some women victims of sexual assault report partial or total amnesia of the event but few studies directly address the topic [11]. In a German study from 2010 found almost 10% of amnesia in a population of women consulting in a forensic department specialized in sexual assault victims. For most women this amnesia followed a psychotropic substance intake (including alcohol), taken willingly or unwillingly [12]. In Geneva, Switzerland, showed that in a population of sexual assault victims consulting in forensic medicine between 2006 and 2012, 31% presented with partial or total amnesia of the assault, for most part under the effect of psychotropic substances taken willingly [13].

Found that 43% of victims consulting in welcome centers in the USA were under the unwanted influence of drugs or alcohol during the sexual assault. In the same type of population in 2015, [14] found that 30.7% of sexual assault victims were intoxicated during the assault and these victims tended to report amnesia more frequently than non-intoxicated victims.

The impact of total or partial amnesia of a sexual assault victim on the future development of PTSD symptoms is not known yet. It is difficult to study as distinguishing the effects of the trauma and the eventual effects of substance intake is hard to assess. The studies on the subject are contradictory [15]. Found a protective effect of amnesia in the development of PTSD symptoms but [16] identified a short period of amnesia of the assault as a risk factor. Dissociative amnesia has been found to be a risk factor to develop PTSD [17].

Aim of the study

The aim of this study is to assess whether the presence of amnesia of a sexual assault in adult women is associated with the presence of PTSD symptoms at the moment of the consultation at the emergency department. We made the hypothesis that amnesia is a risk factor for the development of such symptoms such as deep anxiety, profound distress, eviction or reviviscence symptoms, intense physical or emotional reaction and dissociation.

The population is women consulting in an emergency consultation for sexual victims in Geneva’s hospital, which takes place in the gynecological emergency unit any time of the day. The victims have access to a gynecological and a forensic consultation. The forensic physician describes the assault as told by the victim and reports the physical and psychiatric symptoms observed.

The study was an observational descriptive retrospective study. It took place in the CURML (Centre Universities Romand de Médecine Légale) University Roman Forensic Medicine Center. The data were extracted from the patient files of the gynecological and forensic reports for sexual assault, from January 1st 2015 to December 31st 2017. All victims were women aged 18 and older.

Data collected

In total, 209 files were analyzed. We recorded data on partial or total amnesia of the assault reported by the victim, age of the victim, link between victim and alleged assailant (known or unknown), delay between the assault and the emergency consultation, victim’s intake of alcohol or drugs, willingly or unwillingly (referred to as “intoxication of the victim”), gynecological lesions observed during the examination, PTSD symptoms (intense anxiety, dissociation, extreme sadness, suicidal thoughts, flashback) and psychiatric history. PTSD symptoms were assessed according to the DSM-5 definition of PTSD: intrusion symptoms, avoidance, and alteration in cognition, mood, arousal or reactivity, as observed by the forensic and gynecologist physician during the examination or self-reported by the patient and recorded by the examiners.

Ethical approval

The study was approved by the Cantonal commission of ethic and research. The study participants were not contacted to obtain consent retrospectively for ethical reasons (avoid reactivation of the trauma).

Statistical analysis

Data were analyzed using SPSS 25 software. Descriptive statistics together with bivariate analysis were conducted such as Khi2 independence tests, followed by multivariate analysis such as logistic regressions. The significance threshold was p<0.05.

Population

During the inclusion period, 209 women’s files were reviewed. Women were between 18 and 71 years old and on average 30.1. Amongst them, 96 women (45.9%) suffered from partial or total amnesia of the assault. 96 women knew their assailant and 113 (54.1%) did not. The mean delay between the assault and the consultation was 1.5 days, with a maximum of 30 days. 87.6% of the women consulted during the first three days after the assault.

159 women (76.1%) were under the influence of drugs or alcohol during the assault. 78 patients (37.3%) presented with PTSD symptoms such as extreme sadness, intense anxiety and dissociative symptoms (confusion, agitation, lack of emotion, etc.). More than half of the study population had a psychiatric history (55%) such as an addiction (24.9%), depression (20.6%), and an anxious disorder (9.1%), psychosis (7.7%), a bipolar disorder (3.3%) or a Personality disorder (3, 3%). (See Table 1).

Table 1: Population description.

Bivariate analysis

PTSD symptoms were recorded in 32.3% of the women suffering from amnesia and in 41.6% of non-amnesic patients. Such difference was not significant. (See Table 2). The different types of symptoms were not statistically different between the amnesic and the non-amnesic subjects.

Table 2: Cross table of amnesic subjects presenting with PTSD symptoms.

(P > 0, 05)

• Amnesic patients were significantly younger than non- amnesic (p<0, 05) with a mean age of
• 6 years old for amnesic women and 32.3 for non- amnesic.
• 7% of non-amnesic women were assaulted by someone they knew whereas 75% of amnesic women were assaulted by a stranger. Amnesic women were significantly (p<0,001) more often assaulted by a stranger than non- amnesic women.
• On average, amnesic subjects consulted after 1.0 days and non-amnesic after 0 days, this difference was not significant (p=0, 06).
• 1% of non-amnesic women reported having taken drugs or alcohol against 93.8% of amnesic women. This difference was significant (p<0,001).
• There was no difference between amnesic (32.3%) and non-amnesic women (32.7%) in gynecological lesions (p>0, 05).
• There was no significant difference in psychiatric history among women presenting with or without amnesia, with 8% of non-amnesic women with a psychiatric history and 54.2% of amnesic women.

Multivariate analysis

A multiple linear regression has been conducted with amnesia as the dependent variable and the delay of consultation, the PTSD symptoms, the intoxication, the gynecological lesions, the age and the link with the perpetrator as independent variables. Collinearity has been checked by a correlation matrix showing a Pearson coefficient always minor to 0.8 meaning that no variable was too correlated to another to be considered in the model. The model showed significance with a R2 at 0.28 meaning that 28% of the variance of the amnesic variable was explained by the independent variables. The delay of the consultation, the presence of gynecological lesions, PTSD symptoms and psychiatric history were not significant, confirming the bivariate analysis. Intoxication and the knowledge of the offender had comparable effects on the amnesia (Respective Beta of 0.303 and -0.325).

Partial or total amnesia after a sexual assault is not associated with the presence of PTSD symptoms during the emergency examination of the victim in our sample of 209 women. Amnesia was found to be associated with a younger age, willing or unwilling substance intake and an unknown perpetrator. It was not possible in this retrospective study to discriminate whether amnesia was an effect of an intoxication or a dissociative amnesia, which is a consequence of a traumatic event, or both. These two different types of amnesia may have a different link to PTSD symptoms. The scientific literature shows indeed that per traumatic dissociation (which could include dissociative amnesia) is a known risk factor for the development of PTSD symptoms and characterized post- traumatic stress disorder [18]. It is also possible that some victims did not want to talk about the assault and preferred to declare that they could not remember. We are also unable to estimate the amount and distinguish the types of substance that were taken.

In this study the average delay between assault and consultation was short. The longest delay was 30 days and the vast majority of women consulted in the first three days after the assault. Thus the PTSD symptoms observed were of an acute reaction or even an immediate per traumatic reaction. This cannot allow us to draw conclusions regarding more chronic symptoms. A prospective study with a reevaluation after 3 and 12 months would allow us evaluate the link between amnesia and more long term post-traumatic symptoms.

Half of the sample presented with amnesia (45.9%), which is high in comparison with other studies like the one conducted by [12] on the same type of files but in an earlier period of time. This study found that 31% of the victims presented with amnesia in the consultations taking place between 2006 and 2012. The difference was that they also included victims under 18, with less alcohol and drug intake. Considering the frequency of amnesia, no matter the cause, health professionals working at the emergency departments should be familiar with it and know that it can also be caused by trauma. Health professionals should know that women might be unable to remember and refer details that might be useful in Deciding prophylactic treatment administration for STIs or unwanted pregnancies.

The population of this study was not representative of the general population of women who are victims of sexual assault because it was a selection of women who decided to consult and benefited from a forensic examination. In this population, alleged offenders were for 51.4% unknown to the victims which contrasts with what is usually found in victimization studies in the general population [1]. One might wonder if women victims of unknown perpetrators and presenting with amnesia might decide to consult more in an emergency department and in the short term, looking for a prescription of emergency contraception or STIs prophylactic treatments or looking for evidence to file a complaint. In this study victims suffering from amnesia tend to consult quicker than the other group. Another possibility is that women who remember the events may need a longer reflection time before asking for medical assistance.

This study has limits. All the evaluation was not made by a psychiatrist but by a forensic physician and a gynecologist on call and without a standardized tool. Thus the evaluation of PTSD symptoms was dependent on the background of the physician and their interest in reporting psychiatric symptoms. Although there was a section in the files in which observations regarding psychiatric symptoms must be written down, this section may have been completed differently depending on the physician’s experience and background. A prospective study involving a psychiatrist could be better to discriminate between PTSD symptoms linked to the assault or preexisting psychiatric symptoms. Our study shows that PTSD symptoms are more frequent in case of a psychiatric history. However, it is not possible to know if a psychiatric history is a risk factor for developing PTSD symptoms after the assault or if these symptoms were already there. A better awareness of forensic physicians and gynecologists on psychiatric post-traumatic symptoms could help screen, identify and refer women in need of a specialized psychiatric consultation at short and long term. This study may also lack of statistical power. A bigger population may have succeed to discriminate between different symptoms and to find a link between each symptom and amnesia. It is indeed probable that flashbacks are less frequent when the victim present with amnesia but the link with anxiety, dissociation and avoidance is unclear.

In our sample, amnesia after sexual assault was significantly more frequent in younger women, in case of drug and alcohol intake and when the assailant was unknown. Amnesia was not more frequently reported by women with PTSD symptoms at the moment of the emergency consultation after a sexual assault. A prospective study with a psychiatric evaluation after three and twelve month could provide a better evaluation of possible long term PTSD symptoms associated with amnesia during and after a sexual assault.

Data availability statement

The data that support the findings of this study are available from the corresponding author, CJ, upon reasonable request.

1. Breiding MJ, Smith SG, Basile KC, Walters ML, Chen J & Merrick Prevalence and characteristics of sexual violence, stalking, and intimate partner violence victimization—National Intimate Partner and Sexual Violence Survey, United States, 2011. 2015; 105: 11-12.
2. Survey of sexual violence against women commissioned by Amnesty International Switzerland: Sexual harassment and sexual violence against women are widespread in 2019
3. Campbell R, Dworkin E, Cabral G. An ecological model of the impact of sexual assault on women's mental 2009; 10: 225-246.
4. Breslau N. The epidemiology of trauma, PTSD, and other posttrauma 2009; 10: 198-210.
5. Guina J, Nahhas RW, Sutton P, Farnsworth The influence of trauma type and timing on PTSD symptoms. 2018; 206: 72-76.
6. Benfer N, Bardeen JR, Cero I, Kramer LB, Whiteman SE, Rogers TA, et al. Network models of posttraumatic stress symptoms across trauma 2018; 58: 70-77.
7. Ullman SE, Peter-Hagene LC. Longitudinal relationships of social reactions, PTSD, and revictimization in sexual assault 2014; 31: 1074-1094.
8. Goodman-Williams R, Ullman SE. Posttraumatic stress disorder and measurement invariance in a sample of sexual assault survivors: are symptom clusters stable over time? 2020; 12: 389-396.
9. Aho N, Björklund MP, Svedin CG. Peritraumatic reactions in relation to trauma exposure and symptoms of posttraumatic stress in high school 2017; 8.
10. McCanlies EC, Sarkisian K, Andrew ME, Burchfiel CM, Violanti JM. Association of peritraumatic dissociation with symptoms of depression and posttraumatic stress 2017; 9: 479-484.
11. Jänisch S, Meyer H, Germerott T, Albrecht U V, Schulz Y, Debertin A Analysis of clinical forensic examination reports on sexual assault. 2010; 124: 227-235.
12. La Harpe R, Burkhardt S, Ricard?Gauthier D, Poncet A., Yaron M, Fracasso Factors Influencing the Filing of Complaints, Their Investigation, and Subsequent Legal Judgment in Cases of Sexual Assault. 2019; 64: 1119-1124.
13. Juhascik MP, Negrusz A, Faugno D, Ledray L, Greene P, Lindner A, et An estimate of the proportion of drug?facilitation of sexual assault in four US localities. 2007; 52: 1396-1400.
14. Xifró-Collsamata A, Pujol-Robinat A, Barbería-Marcalain E, Arroyo- Fernández A, Bertomeu-Ruiz A, Montero-Núñez F, et A prospective study of drug-faci litated  sexual   assault   in Barcelona. 2015; 144: 403-409.
15. Möller AT, Bäckström T, Söndergaard HP, Helström, L. Identifying risk factors for PTSD in women seeking medical help after rape. 2014; 9:
16. Bryant RA, Creamer M, O’DONNELL M, Silove D, Clark CR, MCFarlane AC. Post-traumatic amnesia and the nature of post- traumatic stress disorder after mild traumatic brain injury. 2009; s15: 862-867.
17. Brewin CR, Patel Auditory pseudohallucinations in United Kingdom war veterans and civilians with posttraumatic stress disorder. 2010.
18. Candel I, Merckelbach H. Peritraumatic dissociation as a predictor of post-traumatic stress disorder: A critical review. 2004; 45: 44- 50.