Driving under the influence of drugs. Correlation between clinical signs and type of intoxication.

S. Z a n ca n er , R. G io r g e tti , C . D al P o z z o , G . M o lin a r i, R . S n en g h i and S .D .

Ferrara

Centre o f Behavioural and Forensic T oxicology, U niversity o f Padova, V ia F alloppio 50 ,

35121 Padova, ITA LY

IN T R O D U C T IO N

W ith the aim o f highlighting the ro le played by psychotropic substances (alcohol, d ru g s o f

abuse, psychoactive drugs) in causing road accidents, a survey based on clinical and chem ico-

toxicological analyses w as carried out on car drivers in the V eneto region during the w eekends

o f the three-m onth periods June-A ugust 1994 and 1995, and in January 1995 and January

1996.

The aim o f the p resen t study w as to focus on the correlation betw een clinical signs found on

objective exam ination and alcohol and psychoactive substances in drivers' b iological fluids.

M A T E R IA L S A N D M E T H O D S

A scertainm ents w ere carried out in collaboration w ith H ighw ay Police personnel from 1.00

a.m . to 7 .00 a.m . on w eekend nights. Seven team s w orked contem poraneously th roughout the

Veneto R egion, each team com posed o f one doctor w ith experience in ascertaining fitness to

drive within the toxicologico-forensic am bit, one doctor specializing in em ergency treatm ent,

and tw o Italian R ed C ross volunteers.

The m edical personnel w orked inside a R ed C ross am bulance equipped w ith instrum entation for

em ergency treatm ent, m obile on-site exam ination, and chem ical toilet.

P r o c e d u r e

Each toxicologico-forensic ascertainm ent w as preceded by a p relim inary phase for:

- driver identification;

- analysis o f expired air (breathalyser);

- request for inform ed consent to m edical exam ination (verbally o r in writing).

D rivers w ho w ere stopped by the police w ere taken to the am bulance w here, in conditions o f

clinical safety, rapid toxicological and sem eiotic (ocular and neurological) screening w as carried

out. I f this screening revealed one o r m ore signs indicating intake o f psychoactive substances,

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drivers w ere subm itted to com plete toxicologico-forensic ascertainm ent, by m eans o f a

standardized procedure, as follow s:

- drivers w ere asked to give their inform ed consen t to clinical exam ination and sam pling o f

biological fluids;

- any refusals were docum ented and a report m ade to the H ighw ay Police;

- general and m edical details w ere collected;

- drivers w ere subjected to an objective physical exam ination aim ed a t finding signs o f intake

o f psychoactive substances (recent o r p revious in take, in toxication , w ithdraw al

sym ptom s, correlated pathologies); in particular, the fo llow ing param eters w ere all

recorded: m ydriasis and m iosis; presence o f conjunctival congestion , nystagm us; m otor

coordination (finger-to-nose, speech, gait); arterial blood pressure; heart rate;

- blood and urine sam ples w ere taken (double collection fo r "A nalysis" and possib le

"C ounter-analysis");

- a proper chain o f custody w as guaranteed by using special form s fo r recording all

operations involving biological sam ples (sam pling , transport, receipt at laboratory ,

preservation).

T o x ic o lo g ic a l in v e s t ig a t io n

The analytical procedure described in Tedeschi et al. (1992) w as used. C hem ico-toxicological

screening w as carried out using im m unochem ical and chrom atographic techniques, with

confirm ation o f positive results by G C-M S.

R E S U L T S

Rapid clinical screening w as carried out on 2779 drivers. Inform ed consen t to carry out

com plete ascertainm ents w as requested in 532 cases: 52 drivers d id not consen t to medical

exam ination o r d id not supply even a biological sam ple, and w ere charged w ith driv ing under

the influence o f drugs. O f the rem aining 480 drivers, 413 supplied b lood and 372 urine

sam ples. The analysis o f the sam ples gave the fo llow ing results: - BA C > 10m g/100m l 52 .1%

(n=250); - B A C >80 mg/lOOml 31.7% (n=152); - drivers under the influence o f d rugs 11.7%

(n=56).

The general characteristics o f the sam ple population, types o f psychoactive substances identified

and the phenom enon o f m ultiple intake are show n respectively in Table 1 and F igures 1 and 2.

F igures 3-11 show positive clinical findings according to type o f psychoactive substance taken

and in the contro l groups o f unim paired drivers (B A C <50).

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D IS C U S S IO N A N D C O N C L U S IO N S

T he procedure used here covered a special population sam ple, characterized principally by a

high percentage o f m ale drivers under 30, unm arried , em ployed, o f m edium to low degree o f

schooling , and com ing from discos.

The possib ility o f revealing the intake o f d rugs o f abuse by rapid clinical screening has been

reported several tim es (e .g ., T ennant, 1988). The alm ost constant ocular changes caused by

such intake and the ease and rapidity w hich w ith non-invasive clinical tests can be carried out

mean that ocular signs probab ly represent the best m eans o f identifying users o f psychoactive

substances (M cL ane and C arro ll, 1986; C one, 1990; U rey, 1991).

Clinical ocular tests m ust be integrated w ith sem eiological m ethods exploring m otor

coordination (finger-to-nose, w alk-and-turn) and o ther param eters such as heart rate, blood

pressure , signs o f needle m arks, w ithdraw al syndrom es, e tc.) if further details on the type o f

substance taken and the categories o f substances in w hich eye effects are negligible (e .g .,

alcohol, phencyclid ine) are to be identified (K ulberg, 1986).

A nalysis o f resu lts in term s o f correlation betw een clinical ascertainm ent and the presence o f

psychoactive substances in biological fluids allow s the fo llow ing considerations to be m ade:

- clinical eye param eters are far m ore sensitive than others in identifying subjects w ho have

taken psychoactive subtances; in particu lar, m ydriasis (Fig. 3) is found in a very high

percentage o f D U I drivers and in tw o-th irds o f those w ho have taken stim ulants

(am phetam ines and cocaine);

- the m oderate frequency o f m ydriasis in subjects w ho have not taken psychoactive

substances m ay be due to the particular circum stances in w hich they w ere stopped by the

police: the sam ple population w as exam ined at night and had been exposed to excessive

levels o f light and noise in discos;

- conjunctival congestion (Fig. 5) w as very high in those taking cannabinoids and

stim ulants, and w as also considerable in d runk d rivers , consisten t w ith data from the

literature. T he absence o f nystagm us (Fig. 6) w as closely correlated w ith non-D U I

drivers;

- o f the clin ical signs o f lack o f m otor coordination (Figs. 7, 8 and 9), finger-to -nose appears

to be the m ost sensitive, being im paired in a high percentage o f D U I drivers (B A C > 80

m g/100 m L) and those taking opiates (Fig. 9);

- in take o f stim ulants does not cause signs o f im paired m otor coordination , w hich are found

to a lesser exten t than in the control group;

- high heart rate (>100) w as frequently found in those taking stim ulants and cannabinoids

(F ig . 11).

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Interpretation o f resu lts from on-site clinical screening is som etim es d ifficult, due to the

frequent finding o f m ultiple intake o f psychoactive substances. In these cases, observed clinical

effects often depend on unpredictable interactions bew teen substances w hich have opposite

effects on the sam e organ or apparatus. H ow ever, the fact that these drivers m anifestly show

clinical alterations is extrem ely important, since interpretative difficulties on the clinical level can

be resolved by chem ico-toxicological analyses.

The results o f our epidem iological trial indicate the follow ing.

1. In the d river population exam ined, there is a definite problem o f driv ing under the influence

o f alcohol and psychoactive substances.

2. M ost drivers exam ined had taken cannabis or stim ulants.

3. The high num ber o f drivers under the influence o f cannabinoids is an em erging p roblem ,

particularly in view o f the serious im pairing effect w hich cannabis derivates have on driving

ability (Ferrara e t al, 1994). The phenom enon is probably due to the greater ease o f access and

use o f these drugs, w hich m ay now be taken for personal use (depenalized in Italy in 1993).

4. The pharm acological effects o f disinhibition and im paired perception o f risk , confirm ed in

studies on am phetam ines and cocaine (Schm edtje et al, 1988; B urns,1993; F errara et al, 1995),

probably explain the dangerous driving behaviour w hich leads to the greater num bers o f

"Saturday night accidents".

5. R apid clinical screening, m ainly o f ocular and neurological signs, to identify those taking

psychoactive substances is useful in cases in w hich sam ple num bers are high and the expected

frequency o f positive results is quite low (e.g ., w ork environm ent, general driving population ,

drivers requesting renew al o f driv ing licences).

R E F E R E N C E S .

B urns M (1993), Cocaine effects on perform ance. In U tzelm ann H D , B erghaus G , K roj G

(Eds), A lcohol, D rugs and T raffic Safety -T92, V erlag TU V R heinland, K oln, p. 612-619.

C one EJ (1990), T esting hum an hair fo r drugs o f abuse. 1. Indiv idual dose and time profiles o f

m orphine and codeine in p lasm a, saliva, urine, and beard com pared to drug-induced effects on

pup ils and behavior. J A nal T oxicol 14, 1-7.

F errara SD, G iorgetti R, Z ancaner S (1994), Psychoactive substances and driving: state o f the

art and m ethodology. A lcohol D rugs D riving 10, 1-55.

Ferrara SD , Snenghi R, G iorgetti R , Zancaner S, R ossi A, M ontisci F , Fenato F (1995),

Am fetam inici ed analoghi di sintesi: disabilita e crim ine. Bollettino delle Farm acodipendenze e

A lco lism o 18, 45-52.

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K ulberg A (1986), Substance abuse: clinical identification and m anagem ent. Pediatr Clin N orth

A m 33, 325-361.

M cLane N J, Carroll D M (1986), Ocular m anifestations o f drug abuse. S urv O phthalm ol 30 ,

298-313 .

Schm edtje JF, O m an CM , B aker E L (1988), E ffects o f scopolam ine and dex troam phetam ine on

hum an perform ance. A viat Space E nviron M ed 59, 407-410.

T ennant F (1988), T he rapid eye test to detect drug abuse, Postg rad M ed 84, 108-114.

T edeschi L , F rison G, C astagna F, F errara SD (1992). C om prehensive E IA /G C screening and

G C/M S confirm ation o f psychoactive substances in b lood and urine. In: Ferrara SD , G iorgetti

R (Eds). M ethodology in M an-M achine Interaction and Epidem iology on D rugs and Traffic

Safety, A ddiction R esearch F oundation o f Italy , Padova, pp. 147-166.

U rey JC (1991), Som e ocular m anifestations o f system ic drug abuse. J Am O ptom A ssoc 62 ,

832-842.

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T a b l e 1 : C h a r a c t e r i s t i c s o f p o p u la t i o n e x a m in e d .

S e x n° % A g e (y ea rs) 3 o

male 453 94.4 < 2 0 78 16.3

female 27 5.5 21-25 112 40.2

26-30 107 22.3

S ta tu s 31-35 51 10.6

unm arried 412 85.9 >35 51 10.6

married 51 10.6

legally separated 14 2.9 D riv in g e x p e r ie n c e (y ea rs)

divorced 2 0.4

not available 1 0.2 < 1 36 7.5

1-5 190 39.6

C o m in g from 5-10 133 27.7

disco 222 43.3 > 10 110 22.9

other public place 122 25.4 not available 11 2.3

private house 86 17.9

other 50 10.4 S c h o o l in g

none 1 0.2

E m p lo y m e n t prim ary school 29 6 .0

em ployed 420 87.5 m iddle school 255 53.1

unem ployed 34 7.1 high school 183 38.2

student 21 4.4 university degree 8 1.7

pensioner, o ther 5 1 not available 4 0.8

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Figure 1 Psychoactive substancesin biological fluids

cannabinoids cocaine amphetamines opiates benzodiazepines

n. = 56

Figure 2 Alcohol and psychoactive substances Frequency of multiple intake

n = 56%

alcohol and alcohol >80 and alcohol and 2 or 2 or more psychoactive psychoactive more psychoactive psychoactive substances substances substances substances

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F i g u r e s 3 -5 . P e r c e n t a g e s o f p o s i t i v e c l in ic a l s i g n s , a c c o r d i n g to ty p e o f

s u b s t a n c e i d e n t i f i e d b y to x ic o lo g ic a l e x a m i n a t i o n .

Figure 3 % Mydriasis

DUI Cannabinoids Stimulants Opiates Alcohol Negativecontrols

Figure 4 % M io s is20

0DUI Cannabinoids Stimulants Opiates Alcohol Negative

controls

Figure 5 % C o n ju n c tiv a l c o n g e s t io n

controls

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F i g u r e s 6 -8 . P e r c e n t a g e s o f p o s i t i v e c l in ic a l s i g n s , a c c o r d i n g to ty p e o f

s u b s t a n c e id e n t i f i e d b y to x ic o lo g ic a l e x a m i n a t i o n .

Figure 6 % Nystagmus

Stimulants Opiates Alcohol Negative controls

Cannabinoids

Figure 7 % Instab le ga it20

DUI Cannabinoids Stimulants Opiates Alcohol Negativecontrols

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Figure 8 % L ack o f c o o rd in a t io n

DUI Cannabinoids Stimulants Opiates Alcohol Negativecontrols

F ig u re s 9 -1 1 . P e r c e n ta g e s o f p o s it iv e c lin ic a l s ig n s , a c c o r d in g to ty p e o f

su b s ta n c e id e n tif ie d by to x ic o lo g ic a l e x a m in a tio n .

Figure 9 % P a th o lo g ic a l f in g e r - to -n o s e

DUI Cannabinoids Stimulants Opiates Alcohol Negativecontrols

Figure 10 % P s y c h o m o to r a g ita tio n

40

DUI Cannabinoids Stimulants Opiates Alcohol Negative controls

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Figure 11% Heart rate >100

DUI Cannabinoids Stimulants Opiates Alcohol Negative controls

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