The Prevalence o f Drugs in Fatally Injured DriversE. J. W oodhouse1

The National Highway Traffic Safety Administration of the United States Department of Transportation is presently sponsoring programs to determine the occurrence of drugs in both fatally injured drivers and drivers on the road. This paper presents the accomplishments and results of the initial study to determine the frequency with which various drugs are found in fatally injured drivers. Discussed below are the program goals, methodology and results.

GOALSThe goals of this program were to sample the physiological fluids of fatally injured drivers and analyze such samples for the presence of a wide range of drugs, including alcohol, sedatives, stimulants, opiates and tranquilizers. Specific objectives of the program were to develop methods for the acquisition of specimens from fatally injured drivers, to develop a scheme for the analysis of such specimens for drugs, and to implement the analysis scheme on specimens from the fatally injured drivers.

METHODOLOGY

Acquisition o f SpecimensSpecimens of blood, urine, bile, and alcohol swabs from the fingers and oronasal area, were collected from 710 fatally injured drivers. The blood was analyzed for drugs (including alcohol), the urine and bile for drugs (excluding alcohol), and the alcohol swabs for traces of marihuana. Specimens were collected from drivers who were dead on arrival at the hospital. Collection of the specimens was achieved through the co­operation of local medical examiners and coroners with the assistance of Alcohol Safety Action Program (ASAP) Area Directors. Kits for the collection of specimens consisted of plastic tubes for urine and bile, vacutainers for blood, and a set of three swabs marked “left hand” , “right hand” , and “mouth” , with a small vial of alcohol for swabbing purposes. A request for data on the crash victim and circumstances was also mailed for each specimen set acquired. The data requested included the date, time, and location of the crash, the time of death of the victim, the time the specimens were1 Midwest Research Institute, Kansas City, Missouri, U.S.A.

147

148 E. J. Woodhouse

taken, the type of accident, single or multiple vehicle, type of collision, road and light conditions, whether or not the dead driver was at fault, and the sex and age of the victim. The flow of materials for the acquisition of specimens is depicted in Figure 1. The 710 specimen sets were collected between December 1971 and September 1973 as shown in Table 1. The sources of specimen sets are shown in Table II. Only 699 specimen sets were returned in a usable condition. Of these, 97% contained the alcohol swabs, 74% contained urine, 98% contained blood, 75% contained bile and 57% contained urine, blood and bile.TABLE I Receipt o f

Specimen Kits by MonthTABLE II Sources o f Specimens

Month Specimen Kits ReceivedJune to November 1971 0December 1971 8January 1972 1 2February 1972 6March 1972 13April 1972 23May 1972 25June 1972 33July 1972 32August 1972 39September 1972 35October 1972 46November 1972 42December 1972 63January 1973 55February 1973 39March 1973 36April 1973 53May 1973 46June 1973 29July 1973 29August 1973 42September 1 to 4, 1973 4TOTAL 710

Seattle, Washington 76Portland, Oregon 74Burlington, Vermont 51Sacramento, California 48San Diego, California 48East Meadow, New York 46Oakland, California 39Orlando, Florida 36St. Petersburg, Florida 33Atlanta, Georgia 32Cincinnati, Ohio 27Baltimore, Maryland 2 2Minneapolis, Minnesota 17Everett, Washington 17Las Vegas, Nevada 15Tampa, Florida 15Lincoln, Nebraska 1 2Appleton, Wisconsin 11Akron, Ohio 11Albuquerque, New Mexico 11Other Areas 69

TOTAL 710

Analysis o f Specim ensBlood (15 ml), urine (20 ml), and bile (10 ml) specimens were hydrolyzed with 0—glucuronidase at pH 5.0 and 37°C for over 12 hours to liberate any drugs present from their glucuronides. The hydrolyzed specimens were then filtered and passed through 2g XAD-2 resin in columns at pH 9.2. The drugs were eluted from the columns using 15 ml of a 4:6 mixture of dichloroethane/ethyl acetate. The eluates were evaporated to dryness after acidification with hydrochloric acid to reduce the volatility of basic drugs. The residues were reconstituted in 100 jul methanol and subjected to thin layer chromatography and gas chromatography. The general analysis scheme is depicted in Figure 2.

Drugs and Fatally Injured Drivers 149

Figure 1 Diagramatic representation o f the flow o f information and materials for the acquisi­tion o f data on fatally injured drivers.

The alcohol swabs of the hands and oronasal areas were initially eluted with methanol, and the eluate subjected to thin layer chromatography to detect can- nabinoids (marihuana components). This was superceded by a colorimetric test performed on the swab itself using Fast Blue B reagent.

The gas chromatographic technique allowed for the quantification of drugs in urine, blood and bile. Extraction efficiencies of the drugs in question on the XAD-2 columns were estimated using spiked solutions.

The drugs included in the analytical scheme are as shown in Table III. Blood was also analyzed for alcohol using gas chromatography and a head space technique with acetonitrile as an internal standard. Quantification was conducted on all drugs except nicotine, aspirin, salicyclic acid and the cannabinoids. During all analytical procedures, control samples were run simultaneously with the driver specimens to ensure quality control of the analyses.

RESULTSThe frequency with which drugs were found in the body fluids, alcohol washings (swabs) and drivers was noted with the following criteria applying:

Drugs in urine and bile were assigned as being positive only if a level of 1 (Jtg/mlor greater was found.

Drugs including alcohol, in blood were assigned as positive at any level.Aspirin, nicotine and salicyclic acid were taken to be qualitative only and were

assigned positive if found at any level.Marihuana results were treated in two separate batches, those tested by thin

layer chromatography (TLC) and those tested on-the-swab.The drugs are classified into groups, i.e. sedatives/hypnotics, stimulants,

antihistamines/decongestants, tranquilizers, narcotic analgesics, and miscellaneous

150 E. J. Woodhouse

Allow Swabs to Dry for 2 minutes

Add 2 Drops 0.2N

OH

ObserveColorFormat­ion

Receipt of Specimens Urine, Blood, Bile, Face and Finger Washings

(Method Used for Samples 366-710)

YES

Face and N f \I/FingerWashingsAvailable

NO BloodAvail­able

NO UrineAvail­able

NO BileAvail­able

NO

YES

EluteSwabswith

Methanol

Evaporateto

Dryness

Reconst­itute in *5 ml of Solvent 4

YES YES

Take 20 ml

Spot 100 yl on TLC Plate (Note A)

Develop in

Solvent 11 (Note B)

Red coloi Spravindicates WithMarih­ Solutionuana 5

PositiveindicatesMarihuana

Return TLC in Solvent 6

to Confirm

Take up to 10 ml

Dilute1:1withH20

Hydiy

(Not

co­zeeC)

Spot 20yl of I Solution on each of 2 TLC Plates

(Note A)

Develop TLC's in Solvent 2 (Note B)

Reconst­itute

Residue in 100 lil Methanol

Add ldrop Cone. HC1 Evaporate Eluant to Dryness

Plate 1

Spray with

Solution

PositiveIndicateAcidic

andNeutralDrugs

Elute Drugs with

15 ml Solution 7

Plate 2

Spray with

Solut­ions

9 and 1C

Positive with Spray 9 and/or 10 •Indicates Basic Drug

Return TLC in Solvent

1 or 3 using same sprays to Confirm

Rinse Column

with 20ml K aO

© © ©

\l/Inject 5ul of Extract Solution into GC (Note D)

Confirmat­ion and Quantit­ation of Drug Pres. 7T

Add buffer to pH 9.2. Pass liquid through Column, 5cm x lem. Packed with 2g of

Amberlite XAD-2

Mass Spectrom­

eter (Note E)

- * Indicates Report

Figure 2 Analysis o f body specimens for drugs.

Drugs and Fatally Injured Drivers 151Note A:

Note B:

Note C:

Note D:

Note E:

Solvent 1:

Solvent 2:

Solvent 3:

Solvent 4:

Use 20 x 20 cm silica gel G, 250 /J i on glass. Spot extracts, along with standards, 1 .0 cm from lower edge o f plate. Warm the plate slightly when spotting.

Solution 5: Fast Blue B solution — 250 mg in100 ml o f 0.1 N hydrochloric acid. Follow with a spray o f 0.5 N sodium hydroxide.

Develop in glass tank with lid. Use solvent to about 0.5 cm depth. Develop the plate 10 cm above spotting line. Rem ove and dry at room temperature.

Solvent 6: Benzene/chloroform, 3 : 7.

Solution 7: 1,2-Dichloroethane/ethyl acetate, 4:6.

H ydrolyze by adding 3900 Fish­man Units o f j3- Glucuronidase, take to pH 5.2, incubate at 3 7 C fo r 18 hr, centrifuge and filter.

A Bendix 2500 Gas Chromato­graph has been em ployed. Glass columns 5 f t x 4 mm (ID) with 3% OV-1 on 100/120 mesh Gas Chrom Q. Five microliters o f extract solution were injected. Carrier gas is jV2> a t a flo w ° f 50 ml/min. D etector temperature 250 C, injection po rt temperature 240 C. Column temperature between 160 and 265 C depend­ing on drugs being analyzed.

The mass spectrom eter em ployed in this analytical scheme is a Varian M A T CH-4. This is con­nected to the gas chromatograph via a Watson-Biemann helium separator. A Varian 8K core labo­ratory com puter and teletype are em ployed with the GC/MS setup.

Mercuric sulfate solution-suspend 5 g o f mercuric oxide in 100 ml water, add 20 ml concentrated sulfuric acid. Cool and dilute to 250 ml with water. Follow with diphenyl carbazone (DPC) solu- tion-dissolve 5 mg DPC in 50 ml chloroform. Follow this with a 0.1 N solution o f KMnO4 (potas­sium permanganate).

Solution 9: Ninhydrin-commercially available in aerosol bombs from Brink- mann.

Solution 10: Iodoplatinate solution-dissolve 1 g platinum tetrachloride in 100 ml water, mix with 300 ml water containing 10 g potassium iodide. Dilute to 400 ml with water.

Solvent 11: Benzene.

Solution 8:

For acidic and neutral drugs- acetone/chloroform , 1:9.

E thyl acetate/methanol/ammonia,85:10:5.

For basic drugs-ethyl acetate/ methanol/ammonia/benzene, 75: 10:2:13.

Benzene/petroleum ether, 1:1.

152 E. J. Woodhouse

TABLE III Drugs Included in the Analytical ScreenSedatives and Hypnotics Phenobarbital (Luminal) Pentobarbital (Nembutal) Amobarbital (Amytal) Secobarbital (Seconal) Butabarbital (Butisol) Butobarbital (Butethal) Diphenylhydantoin (Dilantin) Glutethimide (Doriden) Methaqualone (Quaalude)Tranquilizers Meprobamate (Miltown) Chlordiazepoxide (Librium) Diazepam (Valium) Chlorpromazine (Thorazine) Promazine (Sparine) Thioridazine (Mellaril) Trifluoperazine (Stelazine)AnalgesicsAcetylsalicylic acid (Aspirin) Salicylic acid Propoxyphene (Darvon)Stimulants and Antidepressants Methylphenidate (Ritalin) Imipramine (Tofranil) Amitriptyline (Elavil) Amphetamine (Dexedrine) Methamphetamine (Desoxyn)

Antihistamines and DecongestantsChlorpheniramineDiphenhydramineTripelennamineMethapyrilenePhenylpropanolamineNarcoticsNalorphine (Nalline)MorphineCodeineMeperidine (Demerol)CocaineMethadone (Dolophine)Hydromorphone (Dilaudid)MiscellaneousDimethyltryptamine (DMT) Diethyltryptamine (DET)LobelineMescalineMethylene dioxyamphetamine (MDA) Quinine2,5-dimethoxy-4-methylamphetamine (STP) NicotineTetrahydrocannabinol (THC)Cannabinol (CBN)

(Table IV). Frequencies are quoted for each individual drug, each drug group and all drugs (other than alcohol, marihuana, nicotine, aspirin and salicyclic acid). The number of cases of the appearance of a drug in a fluid is given in the Table. This is followed by the percentage of fluid samples in which the drug was found.

Table V indicates the number of times nicotine, aspirin, and salicyclic acid were found in urine, blood, and bile samples. Again, the frequencies are followed by the percentages o f fluid samples in which the drug was found.

Table VI shows the blood alcohol concentrations that were found in the 684 blood samples collected. The alcohol level is stratified in quanta of 0.05%. Figures are quoted for drivers who had been drinking alcohol as well as drivers who were drunk,i.e. blood alcohol level > 0 .1 0 %.

Table VII indicates the frequency with which marihuana was found as deter­mined by the swab tests. Results were calculated separately for the TLC test and the on-the-swab test. The differences between swabs tested and swabs available are due to the fact that some swabs were too dirty for testing.

Drugs and Fatally Injured Drivers 153

TABLE IV Frequency with which Quantitated Drugs were Found in Body Fluids.Urine Blood Bile

(51 7 Specim ens) (682 Specim ens) (52 6 Specim ens)Drug N um ber Percentage N um ber Percentage N um ber PercentageA m obarb ital 3 0 .58 3 0 .44 4 0.76B utabarbita l 2 0.39 1 0.15 6 1.14B utobarb ital 1 0.19 2 0.38DPH 1 0.19G lu te th im ide 1 0.19 3 0 .44P ento barb ita l 4 0.77 1 0.15 1 0.19Phenobarb ital 13 2.51 12 1.76 8 1.52S ecobarb ital 3 0.58 2 0 .38

Sedativesand H ypnotics 27 5.22 20 2.93 24 4 .56

A m phetam ine 2 0.39 2 0.29Im ipram ine 2 0.29 1 0.19M etham phetam ine 3 0.44 2 0.38M ethy lphen idate 1 0.19 1 0.15Cocaine 1 0.15

S tim ulan ts 3 0.58 9 1.32 3 0.57

M ethapyrilene 1 0.15P heny lpropanolam ine 7 1.35 6 1.14

A ntih istam inesand D econgestants 7 1.35 1 0.15 6 1.14

M eprobam ate 2 0.39 1 0.15 7 1.33C hlordiazepoxide 2 0.39C hlorporm azine 1 0.19 1 0.15 2 0.38T rifluoperazine 2 0 .39 2 0.38

Tranquilizers 7 1.35 2 0.29 11 2.09

M orphine 1 0 .19 1 0.19H ydrom orphone 2 0.38M eperidine 1 0.19M ethadone 1 0 .19

N arco tic analgesics 3 0 .58 3 0.57

Quinine 1 0.19Lobeline 1 0.19 2 0.29D im eth y ltry p tam in e 1 0.15

A ny drug 49 9.48 35 5.13 47 8.94

TABLE V Frequency with which Nicotine, Aspirin and Salicylic Acid were Found in Body Fluids

Urine Blood Bile(517 specimens) (682 specimens) (526 specimens)

Drug Number Percentage Number Percentage Number PercentageNicotine 284 54.9 57 8.4 91 17.3Aspirin 114 22.1 87 12.8 104 19.8Salicylic acid 29 5.6 7 1.0 20 3.8

154 E .J . Woodhouse

TABLE VI Blood Alcohol Concentrations. N = 684BAC

g/ 1 0 0 ml (%)Number of

DriversPercentage of

TotalCumulativePercentage

0 . 0 0 0 287 42.0 42.00.010-0.049 39 5.7 47.70.050-0.099 37 5.4 53.10.100-0.149 67 9.8 62.90.150-0.199 77 11.3 74.20.200-0.249 62 9.1 83.30.250-0.299 52 7.6 90.90.300-0.349 28 4.1 95.00.350-0.399 19 2 . 8 97.8> 0.400 16 2 . 2 1 0 0 .0> 0 . 0 0 0 397 58.0 ±3.8> 0 . 1 0 0 321 46.9 ± 3.8

TABLE VII Frequency with which Marihuana was Found in DriversNumber of

Swabs TestedNumber of Positives

Per Cent Positives

Totala Per Cent

TLC (357 drivers) 357 sets 6 sets 1 .6 8 N.A.On-the-swab (323 drivers)

Right hand 303 80 26.4 33.8Left hand 305 77 25.2 32.3Mouth 2 0 1 44 21.9 28.1Complete set 323 sets 124 sets*5 38.4 49.2

Complete set of three 195 sets 23 setsc 1 1 .8 15.1swabs clean enough for testing 67 sets*3 34.4 44.1

aAdjusted incidence takes into account that the on-the-swab test yielded 78% positives on tests with smokers in laboratory controlled experiments (U.S. Army LWL Report LWL-CR-08C72).^Incidences in which at least one swab was positive per set.in c id en ces in which all three swabs were positive.

Table VIII gives the frequencies for quantitated drugs (except alcohol). All the 695 drivers from whom at least one body fluid was collected are included in this Table (four collection kits were received containing only swabs). Frequencies are for the drugs with and without alcohol.

The number of times various quantitated drugs (except alcohol) were found in the 395 drivers from whom all three physiological fluids (urine, bile, and blood) were available are given in Table IX. Again, frequencies are quoted for drug groups, any drugs, and for drugs with and without alcohol.

Drugs and Fatally Injured Drivers 155

TABLE VIII Frequency with which Quantitated Drugs were Found — in Drivers — with and without Alcohol

Total Not Combined with Alcohol Combined with Alcohol

Combined with Alcohol (BAC > 0 .1 0 0 g/100 ml (%))

Type o f Drug Number Per Cent Number Per Cent Number Per Cent Numbei: Per CentSedatives and hypnotics 50 7.19 23 3.31 27 3.88 22 3.17Stimulants 14 2.01 7 1.01 7 1.01 5 0.72Antihistamines and decongestants 14 2,01 6 0.86 8 1.15 2 0.29Tranquilizers 18 2.59 5 0.72 13 1.87 7 1.01Narcotic analgesics 5 0.72 1 0.14 4 0.58 4 0.58Miscellaneous 5 0.72 2 0.29 3 0.43 2 0.29Any Drugs 91 13.09 38 5.42 53 7.63 40 5.76

TABLE IX Frequency with which Quantitated Drugs were Found in Drivers for whom all Body Fluids were available

Combined with Alcohol

TotalNot Combined with Alcohol Combined

with Alcohol (BAC > 0 .1 0 0 g/100 ml (%))Type o f Drug Number Per Cent Number Per Cent Number Per Cent Number Per CentSedatives and hypnotics 35 8.86 14 3.54 21 5.32 16 4.05Stimulants 8 2.03 3 0.76 5 1.27 4 1.01Antihistamines and decongestants 9 2.28 3 0.76 6 1.52 4 1.01Tranquilizers 11 2.78 2 0.51 9 2.28 5 1.27Narcotic analgesics 3 0.76 1 0.25 2 0.51 2 0.51Miscellaneous 1 0.25 0 0.00 1 0.25 0 0.00Any Drugs 60 15.19 19 4.81 41 10.38 30 7.59

Table X indicates the number of times nicotine, aspirin, and salicyclic acid were found. All 695 drivers from whom at least one body fluid was collected are included in this Table.

TABLE X Frequency with which Nicotine, Aspirin and Salicylic Acid were Found in Drivers

Type of Drug Number Per Cent

Nicotine 325 46.8Aspirin 198 28.5Salicylic acid 40 6 .6

Sixty of the specimen sets were received from areas which lent bias to their specimens by submitting those which were suspected to be from drug users. Table XI shows what percentages are obtained when these 60 specimens are removed from the analysis.

156 E. J. Wood house

TABLE XI Total Specimens With and Without BiasaSpecimen Kits Total Specimens Total Specimens Minus the

Received 60 Biased Specimens% %

Blood alcohol 58.0 58.24Blood alcohol > 0 .1 0 0 g/100 ml 46.9 46.24Marihuana (on-the-swab, all 3+) 1 1 . 8 11.96Nicotine (in urine) 54.9 56.44Aspirin (in urine) 2 2 .1 23.18Quantitated drugs (drivers) 13.1 12.60aA Chi-square test reveals no significance to any o f these change:s.

Finally, a comparison o f alcohol and sedative use: by drivers, as shown in TableXII, reveals no significant influence on sedative use by alcohol or vice versa. Thepercentage of drivers consuming sedatives with or without alcohol was 7.19; 6.80% ofdrivers consuming alcohol were taking sedatives; and 7.72% of drivers not consumingalcohol were taking sedatives.TABLE XII Number o f Drivers who Used Alcohol and/or Sedatives

Drivers Using Drivers Not UsingSedatives Sedatives Total

Drivers consuming alcohol 27 370 397Drivers not consuming alcohol 23 275 298TOTAL 50 645 695

DISCUSSIONAll drugs2 detected by quantitative analysis (urine, blood, bile) are shown in Table IV. It is apparent that a given drug may be much more detectable in one test than another. A consequence of this is that drug usage would be underestimated if any one of the tests was omitted. This is evident from a comparison of Tables VIII and IX whose frequencies from the total sets of fluids are compared with frequencies from only complete sets. Of course, for a specific drug it may be true that one or two tests would have been sufficient.

Approximately one in 11 urine or bile tests was positive, whereas about one of 20 blood tests was positive. This may be due to the fact that urine and bile are drug concentration centers whereas blood is not.

A positive response to one or more of the quantitated drugs, excluding alcohol, was found in 91 out o f 695 drivers (13%). This figure would have been somewhat higher, presumably, if all samples were subjected to all three tests. (Although almost every sample furnished a blood test, this was not true with respect to urine and bile.)2Excluding alcohol, marihuana, nicotine, aspirin and salicyclic acid.

Drugs and Fatally Injured Drivers 157

Thus, the 13% was an ‘underestimate’ of the persons using these drugs. If only those sets in which urine, blood and bile were all available were analyzed, a figure of 15% would be obtained (60/395). Sedatives and hypnotics accounted for over half the drug occurrence.

It is apparent from Table V that blood and bile tests greatly underestimate nicotine occurrence. The urine test also detected more aspirin and salicyclic acid, but the discrepancy was much less marked.

Tables VI and VII summarize the results of the BAC test and the marihuana tests. Almost 3 of 5 (58%) drivers had been drinking, and nearly half (47%) were “drunk” (BAC >0.10%).

The original test (TLC) for marihuana detected only six users (1.7%), and was obviously not compatible with the second test (on-the-swab technique) (Table VII). The right-hand/left hand/mouth results were homogeneous and detected 28-34% marihuana usage. Forty-nine per cent of the drivers showed a positive on at least one swab. The percentage of three positive marihuana results (based on the number of samples that permitted all three swab tests) was only 15%. These figures take into account that 78% o f marihuana smokers were detected in laboratory tests using the swab technique combined with an on-the-swab color test. It is apparent that the reliability of swab test method for marihuana smoker detection needs evaluation. Of significance in this respect is the fact that lip, forehead, and stomach swabs of six tobacco smokers and six perspiring athletes at the Midwest Research Institute yielded no positives when tested by the on-the-swab technique. Thus, the basic concept of the swab test seems to have merit.

The 50 positive sedative results were examined in an attempt to differentiate between alcohoi presence in sedative and non-sedative users. However, in both the had-been-drinking, and drunk categories there was no difference, i.e. the sedative user was neither more nor less likely to use alcohol than the non-sedative user.

StratificationTo some extent, it was possible to examine the influence (if any) of age3, sex, season4 , region5, time of crash6, at fault or not, and single vehicle — multiple vehicle on the drug responses.

The responses stratified were: had been drinking, drunk, marihuana7, salicyclic acid, aspirin, nicotine, stimulants, tranquilizers, antihistamines and decongestants, sedatives and hypnotics, and ‘any drug’8. However, the three groups, stimulants, tranquilizers, and antihistamines and decongestants did not produce sufficient sample size to yield formal statistical differences.

A summary of influences is:1. The only drug significantly over-involved in the at-fault category was alcohol.2. Alcohol was also the only drug over-involved in single-vehicle crashes.

3 Age categories were: ^ 1 9 , 20-24, 25-29, 30-39, 40-49, 50-59, and >60.4 “Seasons” are: J-F-M (quarter 1), A-M-J (quarter 2), J-A-S (quarter 3), and O-N-D (quarter 4).5“Regions” are: “Northwest” - Oregon, Washington; “West” - California, New Mexico, Nevada;“East” I? Maine, New York, Vermont; “South” - Arkansas, Florida, Georgia, Kentucky, Maryland, Virginia; “Midwest” - Michigan, Minnesota, Nebraska, Ohio, Oklahoma, and Wisconsin. 6Time Categories were: 0000-0059, 0600-1119, 1200-1799, and 1800-2399.7 Using only the results after the method was changed to the on-the-swab method.8Any drug detected by a quantitative analysis (except alcohol).

158 E. J. Woodhouse

3. Alcohol was the only drug upon which time-of-day was a significant influence (with, of course, increasing usage as time increases).4. Region was not a significant stratification for any response.5. Age was a significant factor only with respect to alcohol. (Unfortunately, age was often not known and many of the comparisons were based on small sample sizes.)6 . Sex was a factor with respect to alcohol and nicotine usage, but not otherwise. In both cases males were over-involved.7. The factor season (quarter) was associated with all responses except alcohol and nicotine. Thus, marihuana was found to be a spring-summer ‘activity’, and aspirin a winter ‘activity’.

It is clear that alcohol was by far the most dangerous drug examined in this study. Alcohol was used by many more people than any other drug (except nicotine) and thus, its usage was much easier to analyze statistically. Unfortunately, it was not possible to find enough users of drugs such as amobarbital to draw a statistically significant sample. With the exception of the combination alcohol-sedatives, no synergistic possibilities were examined.

Finally, the drug groups tranquilizers, antihistamines, and stimulants did not furnish a large enough sample to be stratified meaningfully. The study suggests, however, that males were over-represented amongst users of tranquilizers and antihistamines, and that young people were over-represented amongst those who used stimulants.