Forensic Science International 216 (2012) 37–43

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Prevalence of ethanol and illicit drugs in road traffic accidents in the centre ofPortugal: An eighteen-year update

Nadia Costa a, Rosario Silva a, M. Cristina Mendonca a,b,c, Francisco Corte Real a,b,c, Duarte Nuno Vieira a,b,c,Helena M. Teixeira a,b,c,d,*a National Institute of Legal Medicine, Portugalb Faculty of Medicine, University of Coimbra, Coimbra, Portugalc CENCIFOR – Forensic Sciences Centre, Portugald Faculty of Medicine, University of Porto, Porto, Portugal

A R T I C L E I N F O

Article history:

Received 21 February 2011

Received in revised form 23 July 2011

Accepted 15 August 2011

Available online 10 September 2011

Keywords:

Ethanol and drugs of abuse

Road traffic accidents

Centre of Portugal

A B S T R A C T

This study presents the prevalence of ethanol and illicit drugs in fatal road traffic accident victims in the

Centre of Portugal between January 1990 and December 2007. Among the violent deaths, road traffic

accidents presented the highest percentage (around 35%; n = 3095), but decreasing throughout the

years. Accidents were preponderant in males (about 80%; n = 2402), between 21 and 30 years-old.

Accidents involving drivers (55%; n = 1310) were of the most common, being the car the main vehicle

(45%), followed by the motorcycle (40%). An alcohol analysis request was present in 50% of the cases

(n = 1687), but increasing each year. Ethanol concentrations >1.2 g/L, the legal limit in Portugal, were

found in 55% (n = 283) of the cases. Concerning drugs of abuse requests, only 4.4% (n = 137) and 17.3% (58

cases) of the cases included the analysis at the Forensic Pathology Department (FPD) and at the Medico-

Legal Office (MLO), respectively. Among the road accident cases analysed, 18 were positive, mainly in

men (84%), between 21 and 30 years-old; opiates (47.1%; n = 8) and cannabinoids (50%; n = 4) were the

most found, at the FPD and at the MLO, respectively. In conclusion, ethanol was identified as a key factor

to traffic accidents, which explains the definition of specific legislation and methods of enforcement to

prohibit this form of impairing. Nevertheless, ethanol still remains the psychoactive substance most

frequently identified in the blood of divers killed in road-traffic crashes, recommending additional

actions of supervision and control.

� 2011 Elsevier Ireland Ltd. All rights reserved.

1. Introduction

It is well established that alcohol impairs driving ability andincreases the risk of accident [1] and, thus, fatal road trafficaccidents, incidents and crashes remain as common occurrences[2]. The causes of road traffic crashes usually involve a combinationof factors related with the vehicle, the environment and the humanelement [3]. The over-consumption of ethanol plays an increasingrole in accidents, once sensory, cognitive and motor functions areimpaired [4–6]. Due to the continuing change in drugs availableand use trends, the involvement of substances in road trafficaccidents can vary each year or decade [7,8]. Political attitudestowards alcohol and drug use by drivers differ among differentcountries, reflected in road-traffic legislation, police powers toenforce the law and sanctions for offenders [3]. In Portugal, the

* Corresponding author at: Instituto Nacional de Medicina Legal, Jardim Carrilho

Videira, 4050-167 Porto, Portugal. Tel.: +351 222073856; fax: +351 222018069.

E-mail address: helenateixeira@dcinml.mj.pt (H.M. Teixeira).

0379-0738/$ – see front matter � 2011 Elsevier Ireland Ltd. All rights reserved.

doi:10.1016/j.forsciint.2011.08.013

legislation related to road traffic and safety is laid down in the RoadTraffic Code and specific additional legislation [9]. Since 1998, itstates that all the drivers and pedestrians involved in road trafficaccidents (fatal or not) must be tested for ethanol and illicit drugs.Driving under the influence of substance that affects the proficiencyof that activity is forbidden. For ethanol, there are three legal limits(0.5 g/L, 0.8 g/L and 1.2 g/L) with different penalties [9]. Concerningillicit drugs, as a consequence of the introduction of new legislationin Portugal, in 2007, regarding the onsite control of driving under theinfluence of psychotropic substances, more cases could be analysedand surveyed. Furthermore, experts should be aware of themandatory request of drugs of abuse in cases of fatal road trafficaccidents. Portuguese law states that it is forbidden to drive a vehicleif defined substances (known to impair driving) are detected byblood toxicological analysis after an oral fluid on site positivescreening test or after immunoassay screening tests in urine. It is,thus, a per se legislation, based on the German law, as was followedby other countries [10].

The European road traffic safety plan aimed to reduce thenumber of accident victims in the European Union (EU), in 2010,

N. Costa et al. / Forensic Science International 216 (2012) 37–4338

being ‘‘driving under the influence of alcohol and drugs’’ aphenomenon described as one of the most disturbing accidentrisk factor. Thus, guidelines has been recommended to all EUcountries as a way to face the problem, which includes theapplication of an harmonized procedure to detect illicit drugs in alldrivers involved in fatal accidents, the use of onsite screeningdevices, as well as an adequate training for the police officers. Allthese initiatives contributed to decrease the deaths due to roadtraffic accidents [11].

During the studied period (between 1990 and 2007) newlegislation concerning road traffic ethanol and illicit substancesanalysis was introduced and more epidemiological studies haveconfirmed ethanol as the most frequently detected drug in deathsfrom all causes, and from traffic accidents in particular. This studypresents and discusses the toxicological ethanol and illicit drugsresults of blood samples taken in road traffic accidents, in theCentre of Portugal, between January 1990 and December 2007,aiming to assess the prevalence of these psychotropic substancesamong deaths. The most recently published data from Portugal isfrom the 80s, when different mentalities, habits and legislationwere present and only ethanol was requested and analysed[12,13]. Thus, no comparison with the current results is possible,which will be discussed on the basis of our contemporary legalmedicine system and reality.

2. Material studied

This study has been carried out by the National Institute of LegalMedicine of Portugal (INML, I.P), being all the samples collected byforensic pathologists from two different departments: the ForensicPathology Department (FPD) of the Centre Branch of the INML, I.P.(from January 1990 to December 2007) and the Medico-Legal Office(MLO) of Figueira da Foz (from April 2001 to December 2007), which[(Fig._1)TD$FIG]

Fig. 1. Road traffic accidents distribution: by year, in the FPD (a) an

depends on the Centre Branch administration and has initiateactivity in April 1st 2001. Samples were sent, in specific containerswith sodium fluoride as preservative, to the Forensic ToxicologyLaboratory of the INML, I.P. Centre Branch, for analysis purposes.Ethanol was analysed in blood by head-space gas chromatography(GC) with flame ionization detection and the illicit drugs (opioids,cannabinoids, cocaine and amphetamines) by GC mass-spectrome-try.

As data material of the present study, 9409 and 1219 autopsieswere checked out for road traffic accidents from the FPD and fromthe MLO, respectively. The target population consisted of peoplekilled in road traffic accidents and the main goal was to determinethe prevalence of ethanol and illicit drugs, which are the twosubstances that, by specific law, must be quantitatively confirmedin road traffic fatal accident victim’s blood.

Assessment of the examination protocols was conducted bymeans of a tabular database according to the following criteria: year,month, age, sex, driver/passenger/pedestrian and ethanol/illicitdrugs requests and results. All these variables were studied and allthe pertinent data registered, separated and statistically treatedwith the SPSS program (Statistical Package for Social Sciences).

3. Results

3.1. Number of cases

At the Forensic Pathology Department (FPD) of the CentreBranch, a total of 9409 autopsies were performed between January1990 and December 2007, 3095 (35.8%) of them concerning roadtraffic accident victims, which is the total number of road trafficfatalities autopsied during this period. The majority of road trafficaccidents were from the 90s (66.8%; 2067 cases), versus 1028 cases(33.2%) from the 2000s [Fig. 1(a)]. At the Medico-Legal Office

d in the MLO (b); by month, in the FPD (c) and in the MLO (d).

[(Fig._2)TD$FIG]

Fig. 2. Road traffic accidents distribution by ethanol requests, in the FPD (a) and in the MLO (b).

N. Costa et al. / Forensic Science International 216 (2012) 37–43 39

(MLO) of Figueira da Foz, 1219 autopsies were performed fromApril 2001 to December 2007, 336 (31.8%) of them on road trafficaccidents victims (representing all the road traffic fatal victimsautopsied during this period, which is also the total number of roadtraffic fatalities autopsied during this period [Fig. 1(b)].

3.2. Year and month distribution

Concerning the FPD autopsies, we found that 1991 had thehighest number of fatal road traffic accidents (253 cases; 8.2%) and2006 the lowest (only 77; 2.5%) [Fig. 1(a)]. Regarding the MLO,2002 was the year with highest prevalence (61 cases; 18.2%) and2007 with the lowest (only 23 cases; 6.8%) [Fig. 1(b)]. August hadthe highest number of cases at the FPD (359; 11.6%) and Januaryand April the lowest [Fig. 1(c)]. At the MLO, October showed thehighest number of cases (43; 12.8%) and February and Novemberthe lowest (17 cases; 5.1%) [Fig. 1(d)].

3.3. Sex and age distribution

At both forensic pathology departments, the highest number ofroad traffic accidents occurred in males: 77.6% (n = 2402) at theFPD and 81.8% (n = 275) at the MLO. When crossing sex and age, itis concluded that the most affected age group was between 21 and30 years-old mainly in men: 21.1% (n = 508) at the FPD and 24.7%(n = 68) at the MLO.

3.4. Drivers/passengers/pedestrians distribution

This information was only available in 2542 cases of the FPDand in only 181 cases of the MLO. Among these FPD autopsies,51.5% of the deaths (1284 cases) involved drivers, followed bypedestrians (29.9%; n = 744) and passengers (8.6%; n = 470).Concerning the 181 MLO cases, drivers were, once again, thehighest detected group (56.9%; n = 103), followed by pedestrians(28.2%; n = 53) and passengers (14.9%; n = 27).

3.5. Vehicle distribution

The car was the most frequent vehicle involved in both FPD (905cases; 44.5%) and MLO (69 cases; 48.9%) fatal accidents of thereviewed cases. The motorcycle was the second most prevalent

vehicle: 42.0% (n = 842) and 36.2% (n = 51) for the FPD and MLO,respectively. The third highest percentage was found for a groupnamed other, encompassing all other vehicles (e.g., tractors, trucks,etc.), with 7.1% (n = 138) of the cases at the FPD and 7.8% (n = 9) atthe MLO. Finally, the bicycle was also present in 6.4% (n = 129) and7.1% (n = 10) of the cases, respectively for FPD and MLO.

3.6. Ethanol requests

Concerning the road traffic accidents analysed at the FPD, 54.5%included ethanol analysis request (1687 cases), being 1998 theyear with the highest number of demands. However, it isimportant to notice that since 1993 there was an increase inethanol requests, very deeply felt in 1998 [Fig. 2(a)]. At the MLO,75.0% of the cases (n = 252) included ethanol analysis request,being 2005 the year with the highest number of requests. Onceagain, through the years an increase in ethanol requests per roadaccident death was observed [Fig. 2(b)].

3.7. Ethanol positive results

From the 1687 cases of the FPD subjected to ethanol analysis,523 were positive (31.0%); 1992, 1995 and 2002 showed thehighest number of positive cases and 93.3% of the cases withethanol requested were from men (488 cases) and only 6.7% (35cases) from women. Ethanol detection was mainly from individu-als aged between 21 and 30 years-old (26.6%; 130 cases) [Fig. 3(a)].Considering the 252 cases of the MLO subjected to ethanol analysis,118 were positive (46.8%) and 2004 presented the highest numberof positive cases (n = 24; 20.3%). Once again, the highest numberwas from men (95.1%; 113 cases) [Fig. 3(b)] and between 21 and 30years-old (21.2%; 24 cases) [Fig. 3(b)].

3.8. Ethanol quantitative results

At the FPD, the great proportion of positive cases correspondedto a Blood Alcohol Concentration (BAC) �1.2 g/L (54.1%; n = 283),followed by a BAC �0.5 g/L (27.5%; n = 144) and by a BAC between0.8 and 1.2 g/L (11.1%; n = 58). The lowest percentage corre-sponded to 0.5 < BAC < 0.8 g/L (7.3%; n = 38) [Fig. 3(c)]. At theMLO, the same distribution was encountered, with the highestresults obtained over the upper legal limit (BAC �1.2 g/L), with

[(Fig._3)TD$FIG]

Fig. 3. Ethanol requests distribution: by age/gender in the FPD (a) and in the MLO (b); Ethanol BAC percentage distribution in the FPD (c) and in the MLO (d).

N. Costa et al. / Forensic Science International 216 (2012) 37–4340

59.3% of the cases (71), followed by a BAC �0.5 g/L (20.3%; n = 26)and by a BAC between 0.8 and 1.2 g/L (13.0%; n = 16). Finally, thelowest percentage was found for the interval 0.5 < BAC < 0.8 g/L(7.3%; n = 10) [Fig. 3(d)].

3.9. Ethanol positive results and sex and age distribution

At both forensic pathology departments, the highest numberof positive results occurred in males: 93.5% (n = 2406) at the FPD

[(Fig._4)TD$FIG]

Fig. 4. BAC distribution: by gender, in the FPD (a) and in th

and 95.1% (n = 275) at the MLO. In both cases, BAC �1.2 g/Lreached the highest number of cases, in around 96% (n = 276) ofthe males and 4% (n = 7) of the females [Fig. 4(a) and (b)]. At theFPD, the most affected age group of the positive ethanol resultswas between 21 and 30 years-old (25.4%; n = 130), being BAC�1.2 g/L the most found concentration (28.3%; 80 cases)[Fig. 4(c)]. Only one case with this BAC had no informationabout the victim’s age. Once gain, the most affected age group atthe MLO was between 21 and 30 years-old (22.8%; 28 cases),

e MLO (b); by age, in the FPD (c) and in the MLO (d).

[(Fig._5)TD$FIG]

Fig. 5. Road Traffic Accidents distribution: by drugs of abuse request per year, in the FPD (a) and in the MLO (b); by drugs of abuse request and gender, in the FPD (c) and in the

MLO (d); by drugs of abuse request and age, in the FPD (e) and in the MLO (f).

N. Costa et al. / Forensic Science International 216 (2012) 37–43 41

being the highest percentage achieved for BAC �1.2 g/L (27.4%;20 cases) [Fig. 4(d)].

3.10. Illicit drugs requests

Among all road traffic accidents analysed at the FPD, only 4.4%included illicit drugs analysis request (137 cases), being 2004 theyear with the highest number of demands (44). Since 2000 thenumber of requests increased [Fig. 5(a)]. At the MLO, only 17.3% ofthe cases included illicit drugs analysis request (58 cases), being2006 the year with higher demands for drugs of abuse detection(39.6%; 23 cases). However, there was a marked increasing on therequests since 2005 [Fig. 5(b)]. Analysing by gender, almost 80.0%(n = 223) of the males involved in road traffic accidents had nodrugs of abuse request [Fig. 5(c) and (d)] and the most importantage interval with few drugs analysis requests was between 21 and30 years-old (about 20%; n = 52). At those ages the consumption ofsuch substances has higher incidence; indeed, only around 30.0%(n = 24) of the individuals aged between 21 and 30 years-old hadthis toxicological determination [Fig. 5(e) and (f)].

3.11. Illicit drugs results

Only 13 cases (9.5%) were positive for drugs of abuse at the FPD,remarking the year 2005 with 6 cases, 2007 with 4 cases and 1993,2001 and 2006 with only one positive case. At the MLO, a total of 5positive cases were detected, accounting for 8.6% (n = 5) of the totalrequest number. Among the positive cases detected at the FPD,

opiates were present in 47.0% (n = 8) of the cases, cocaine andmetabolites in 35.3% (n = 6) and cannabinoids in 17.7% (n = 3).However, different percentages were achieved at the MLO, beingcannabinoids the main detected group, with 50.0% (n = 4) of thecases, followed by cocaine and metabolites (37.5%; n = 3) andopiates in only 12.5% (n = 1).

4. Discussion and conclusion

Violent deaths accounted for 76.8% (n = 6374) of the autopsiesperformed at the FPD and 66.7% (n = 681) at the MLO, with roadtraffic accidents having the highest percentages: 35.8% (n = 3095)at the FPD and 31.8% (n = 336) at the MLO. August was the mosttroubling month, when there was the highest number of fatal roadtraffic accidents autopsied at the FPD, as also stated by otherauthors [14–17]. However, at the MLO October was the monthwith highest prevalence, in agreement with the study performedby Sivak (2009), in which a systematic seasonal variation in theroad fatality rate was found, with the highest rate in October andthe lowest rate in March [18]. The highest number of road trafficaccidents in August might be linked with Portuguese vacations andmost frequent travelling, or even due to high temperatures, sleepdisorders, especially during the afternoon, leading people to fallasleep at the wheel, or with the nightlife before a day-work andconsequent short night-sleep, as well as with nightlife-associatedalcohol consumption, which is more frequent in holidays [19].However, there is no clear explanation for the different scenarioachieved at the MLO. Thus, it can be assumed that accidents that

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occurred mainly in October were possibly due to the changing ofweather conditions, the early days of rain and consequentassociation to roads with oil and water, resulting in an imminentcomponent risk, as well as the darkness increasing in this time ofthe year, associated with the hour-changing that occurs [18].

As already reported by other authors, the proportion of meninvolved in road traffic accidents exceeded that found in women, inall age groups, with about 80% of the cases, at both the FPD andMLO [2,3,13,20,21]. Despite Portuguese culture have suffered deepchanging over the years, with a higher number of women withactive and professional activities, and with driving licence, therewill always be a major number of male drivers, as also stated byother authors [22,23]. Further reasons for the sex differencesencountered only could be discussed on the basis of anepidemiological study, which was not the focus of the presentpaper.

In this study, 55% of the cases were associated with drivers,being the car the main vehicle involved in fatal accidents (45% ofthe cases), followed by the motorcycle (approximately 40%). It wasnot surprising that the highest percentage was observed amongdrivers since they represented the largest number of casesexamined [11,24], as it is not unexpected the most frequentvehicles involved, since car and motorcycle are the most frequentlyused, namely near cities [2,15]. The Portuguese legislationobligates autopsy in all road traffic fatal accident victims, includinginvolving pedestrians. The percentage of accidents involvingpedestrians was, as expected, lower that those with drivers, whichmight be also due to additionally measures carried out in ourcountry during the last years to achieve those results, such asairway construction of pedestrian crossings. Our results, which areidentical to those found by others [25], are in agreement with thesestrategies, since during the analysed years passengers wereinvolved in around 30% (n = 473 at the FPD and n = 27 at theMLO) of the fatal accidents, affecting predominantly people agedbetween 71 and 80 years.

Among the analysed road traffic accidents, only around 50%(n = 1687) included ethanol request. However, through the years astrong increasing in ethanol requests could be observed. The lack ofethanol requests on fatally injured victims in road traffic accidentsin 1990 and 1992 was probably due to the insufficient legislation inour country, which was reinforced since 1998, through thehighway code as well as by means of own legislation: Decree-Law No. 24/98 of 30 October, now repealed by the Decree-Law 18/2007 of May 17. After the introduction of this specific legislationthe number of blood samples submitted by the pathologist fortoxicological analysis increased. The other cases where there wasno ethanol request were related to the following situations: –drivers or pedestrians who where hospitalized and had asubsequent over 24 h survival and, according to the rulesimplemented at the FDP of our Institution, ethanol is not requiredin such situations; – cadavers with certain constraints, such asthoracoabdominal trauma or other trauma that led to biologicalsamples absence (namely blood), eliminating the possibility of anethanol analysis; – all the cases with the suspicion of a postmortemethanol synthesis, such as putrefaction signs, which were excludedfrom an ethanol analysis due to the unreliable results, which arecrucial both for legal and insurance purposes.

In agreement with the results achieved by others [26], our studydemonstrated that 31% (n = 523) of the road traffic accidents thatincluded ethanol request at the FPD were positive. Although 1992,1995 and 2002 were the years with the highest number of positivecases; this data do not means a decreasing number, since thepercentage obtained at the FPD comprised two particularly distinctdecades, with a consequent higher number of studied years andcases when compared with the study performed at the MLO.Furthermore, the apparent reduction of positive ethanol results

should be also related with the beginning of activity of other MLOs(such as the analysed in this report), with the consequentreduction of autopsies at the FPD. This fact can be confirmed bythe results achieved at the MLO, where 50% (n = 118) of the caseswere positive for ethanol, in agreement with data from othercountries [2,27].

The great majority of ethanol positive cases were above 1.2 g/L(54.1% at the FPD and 59.3% at the MLO), which is the maximumlegal limit of the Portuguese law. Statistics from different countrieshave shown that the driver’s blood-alcohol concentration was alsoabove the prescribed statutory limit in 20–50% of all crashes [28–32]. August (at the FPD) and September (at the MLO) presented thehighest percentages, which might be due to both natural (such asweather) and social (such as celebrations in holidays) factors[16,33]. Once again, males (about 95%; n = 276) aged between 21and 30 years-old (about 25%; n = 80) were prevalent, which is inagreement with reports from others [34]. The relative risk ofinvolvement in a crash after consumption of alcohol has beendetermined in a number of case-controlled roadside surveys,demonstrating that the probability of being involved in a crashappreciably increases as the driver’s BAC passes 0.5–0.8 g/L [35].On the other hand, the high median BAC (1.6 mg/mL) achieved insome studies indicates that many drivers are heavy drinkers andalcoholics [1].

Concerning the requests for drugs of abuse, only 4.4% (n = 137)of the cases included its determination at the FPD, with a smallincrement since 2000; at the MLO, only 17.3% (58 cases) includedthis request, also with an increase since 2005. As in other countries[36], the increased consumption of illicit substances in our countryleads to a growing concern related to the individual’s health, aswell as to all risky behaviors and delinquency, including in roadtraffic accidents. The introduction of specific legislation in Portugalconcerning driving under the influence of alcohol and psychotropicsubstances has alerted all pathologists with regard to theobligation to request illicit drugs in all fatal road traffic accidents.Among the road accident cases analysed, 18 were positive, mainlyin men (84%), aged between 21 and 30 years-old, being the opiates(47%; n = 8) and the cannabinoids (50%; n = 4) the most prevalentgroups. The positive results achieved at the FPD are in agreementwith other studies which reported opiates in 47% (n = 8) of thecases, cocaine and metabolites in 35% (n = 6) and cannabinoids in18% (n = 3). However, different percentages were achieved at theMLO, being cannabinoids the main detected group (50%; n = 4),followed by cocaine and metabolites (38%; n = 3) and opiates (13%;n = 1). Nevertheless, it should be noticed that the study performedat the FPD involved two decades with different consumptionpatterns, since in Portugal the 90s were characterized by opiatesconsumption and the 20s by cannabinoids [37].

In studies from various countries concerning fatally injureddrivers, the incidence of illegal drugs is variable as is the frequencyof the different substances detected. Previous studies performed inother countries stated different realities. In a Spanish study, theauthors concluded that the most frequently found illicit drug wascocaine, followed by opiates, cannabis and amphetamine [38].However, in an Australian study, cannabinoids were detected in13.5% of fatally injured drivers, followed by opioids (4.9%) andstimulants (4.1%) [7]. Nevertheless, a recent Swedish study statedthat illicit drugs were present in 7.2% of all fatalities, withprevalence of amphetamine and cannabis, and less presence ofcocaine [3]. The popularity and availability of recreational drugsdiffers between countries and this will also be reflected in thefindings in postmortem toxicology of drivers killed in road-trafficcrashes [39–41].

Despite the positive results of only about 9.5% (n = 13), it is notpossible to conclude that there is a low consumption of suchsubstances when combined with driving. Therefore, as above-

N. Costa et al. / Forensic Science International 216 (2012) 37–43 43

mentioned, the search for drugs was performed only in 4.4%(n = 137) (FPD) and 17.3% (n = 58) (MLO) of the traffic accidentautopsies, excluding all the victims where such search was noteven considered. Also relevant is the fact that the higher number ofcases where no drugs of abuse were required corresponded topeople aged between 21 and 30 years-old, which is not desirablesince these are ages most probably associated with consumption ofthose substances. This data reinforces the importance of furtherincrement of complete screening for illicit drugs by forensictoxicologists and pathologists, and not only focus the analysis ofroad traffic accidents on alcohol detection.

In conclusion, ethanol was identified as a key factor to trafficaccidents, recommending the enforcement of specific legislationand methods for supervision and control of its consumption indrivers. Furthermore, the presence of illicit drugs of abuse in roadtraffic accidents should deserve further attention and supervision.

Acknowledgements

We thank all the Forensic Pathologists of the Centre Branch andof the Medico-Legal Office of Figueira da Foz of the NationalInstitute of Legal Medicine of Portugal (INML, I.P.) for all theautopsies performed and analysed in this manuscript and all theForensic Toxicologists of the Centre Branch for all the toxicologicalanalysis.

We also thank Dr. Sandra Curado for all the support alwaysgiven in the bibliographic research.

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