Hair testing and self-report of cocaine use

Hair analysis is a useful tool in both clinical and forensic fields: it allows information about drugs of abuse (DOA) consumption to be obtained. However, in spite of analytical results, sometimes patients continue to deny using drugs or, on the contrary, insist on describing themselves as severe drug addicts; indeed there are often considerable difficulties in getting truthful statements about the real amount of drugs used. In this study we have tried to compare cocaine concentration in hair samples with self-reported drug intake. We enrolled 113 subjects (61 Africans, 52 Caucasians) who had been recently sent to jail. They were asked to tell about their use of illicit drugs during the last three months and then submitted to hair analysis. Hair segments (3 cm) were analyzed by GC-MS for amphetamines, cocaine and opiates. Useful data was obtained from 82 subjects, separated into two main groups on account of ethnic origin (African or Caucasian) and divided further into daily, weekly and monthly users. The results showed qualitative results and self-reported consumption to be in good agreement, although the correlation between frequency of consumption and concentration in hair revealed sometimes higher concentrations in contrast with the admission of low consumption. There was a definite separation between occasional and daily use (especially in Caucasian people), while concentrations found where weekly use was reported were more variable. Concentrations of cocaine measured in Africans' hair were much higher than in Caucasians'. Even if this study is exclusively based on self-report, it provides some interesting information in order to differentiate the frequency of consumption, and especially underlines the great importance of ethnic bias on hair analysis.     

Clinical applications of hair testing for drugs of abuse--the Canadian experience

During the last 2 decades there has been a substantial increase in illicit drug consumption in North America. It has been repeatedly shown that the personal history of drug use is far from being accurate. Fearing legal consequences and embarrassment of admitted illicit substance use, most users tend to deny or, to under-report illicit drug consumption. These facts have stressed an urgent need for a biological marker which does not lose its sensitivity within a few days after the end of exposure and which may yield a cumulative reflection of long term exposure to illicit drugs. Hair analysis has emerged as such a marker. A variety of illicit and medicinal compounds have been shown to be incorporated into hair including trace metals, barbiturates, amphetamines, opiates, phencyclidine, cocaine, nicotine and cannabis. Hair analysis for drugs of abuse provides long-term information on an individual's drug use; its window of detection is limited only by the length of the hair and typically, ranges from a week to several months. After establishing and validating several hair tests during the last decade, we have analyzed over 1000 hair samples for different drugs of abuse. We used RIA for screening and GC-MS for confirmation of positive results. The aim of this report is to illustrate the diagnostic usefulness of hair testing in different age groups (newborns, children, adults) and circumstances: (criminal cases, athletes, child custody cases, etc.).     

Hair analysis of opiates in mothers and newborns for evaluating opiate exposure during pregnancy

The increasing interest in toxicological hair analysis as a marker of human exposure to xenobiotics such as illicit substances or therapeutic drugs, has been made feasible by the extension of mass spectrometry, a highly sensitive method of detection. A newborn exposed to drugs in utero can suffer from a varying degree of withdrawal syndrome, a few days after birth. If of opiate origin, the withdrawal syndrome can be treated with morphine, among other therapeutics, but it is not easy to diagnose because of atypical symptoms presented by neonates and especially when maternal drug addiction has not been revealed. To assess and measure toxicological factors linked with the appearance and the severity of this syndrome, maternal and neonatal matrices such as urine, meconium and hair were collected during a protocol approved by the ethical committee. Opiates in particular were measured with GC-MS and potential combined dependences (cannabis, cocaine, amphetamine, LSD and benzodiazepines) and/or substitutive therapeutics (methadone or buprenorphine) were also assessed in 17 mother/neonate couples. Gestational opiate exposure profiles were drawn up and linked with the observed withdrawal syndromes. A withdrawal syndrome seems to appear more frequently after foetal exposure to an association of opiates/substitutive molecules (8 out of 10 withdrawal syndromes observed in this study), although the impact of cocaine and benzodiazepines must also be taken into account. The results obtained in neonatal hair make it possible to affirm foetal drug exposure and are in accordance, for the majority, with the appearance of a neonatal withdrawal syndrome (NWS). Neonatal hair analysis could contribute to assess in utero exposure to opiates, particularly when results in urine and meconium are negative or when these matrices are not available.     

Hair analysis by using radioimmunoassay, high-performance liquid chromatography and capillary electrophoresis to investigate chronic exposure to heroin, cocaine and/or ecstasy in applicants for driving licences

The present paper describes an integrated diagnostic strategy to check the physical fitness of subjects, formerly users of illicit drugs, to obtain a driving license, after having quit their addiction. According to the Italian law, applicants for a driving license with a history of drug abuse must give evidence to have quit this behaviour and to show no risk of relapse in the future. To prove this, at our institute, they undergo medical examination, hair analysis and a urinalysis program on eight seriate samples, collected over about 40 days. About 700 subjects per year are investigated with this strategy. The hair samples are screened for opiates (morphine), cocaine and ecstasy, the most abused illicit substances in our region, by using commercial radioimmunoassays adopting cut-off levels of 0.1 ng/mg. All positive samples and about 10% of negatives are confirmed by high-performance liquid chromatography. Further confirmation of results can be carried out by capillary electrophoresis (and/or GC/MS or MS/MS). In 1998, the prevalence of positives for morphine, cocaine and ecstasy was 4.8, 11.3 and 2.6%, respectively. In this year, for the first time, the percentage of hair samples positive for cocaine was greater than that for opiates. The results of this integrated diagnostic strategy are presented and discussed, with particular emphasis on the comparison between hair analysis on a single sample and seriate urinalyses (on eight samples).     

Fatal cocaine interactions: a review of cocaine-related deaths in Bexar County, Texas

Although cocaine is a widely abused illicit substance that is known to cause death, deaths due to its use appear to occur in a minority of those who use it. This report was designed to review drug-related deaths due to cocaine, and the concomitant use of other drugs/medications. A retrospective review of drug deaths at the Bexar County Medical Examiner's Office in San Antonio, Texas, was undertaken for cases where cocaine was one of the drugs implicated in causing death. Analysis was performed comparing the concentrations of cocaine and benzoylecgonine present and the absence or presence of other drugs. The data obtained showed that cocaine was toxic over a large range with deaths occurring at concentrations ranging from 0.01 to 78 mg/L. Analyses also indicated an increased lethality when cocaine is used in combination with ethanol, heroin, opiates, and antidepressant/antipsychotic medications, which is consistent with previous reports and research. Antihistamine data showed that there may be relationship between increased toxicity and co-ingestion, although more research is necessary.     

Simultaneous hair testing for opiates, cocaine, and metabolites by GC-MS: a survey of applicants for driving licenses with a history of drug use

A sensitive GC-MS method for the simultaneous determination of opiates, cocaine, and metabolites in hair at a cut-off level of 0.1 ng/mg was adopted to assess past exposure to these drugs in applicants for driving licenses with a history of drug use. The sampling protocol consisted of collection of one hair (sample A, 5-cm length) and one urine sample. When hair and urine (EMIT Syva, cut-off levels: 0.3 mg/l for opiates, 0.15 mg/l for cocaine, GC-MS confirmation of positives) were both positive or negative the protocol was concluded. In the other cases, the assessment of 'current exposure' to drugs was carried out, in order to avoid seriated random urinalysis, by collecting a second hair sample (sample B) 6 weeks later and analysing the proximal 1-cm segment. Out of the 214 'A' hair samples analyzed, 14 (6.5%) tested positive for morphine and/or 6-acetylmorphine (6AM), and 26 (12%) for cocaine and/or benzoylecgonine (BE), whereas none of the samples tested positive for both drugs. Levels between 0.1 and 1 ng/mg of the single analytes were found in eight out of the 14 morphine-6AM positives (57%) and in 18 out of the 26 cocaine-BE positives (69%). The time course of positive cases showed a progressive decrease of morphine-6AM positives and a corresponding increase of cocaine-BE positives within the study period September 1995-February 1999. No cases with positive urine and negative hair were observed. Among the 40 positive cases, seven (four and three for opiates and cocaine, respectively) were found to be 'currently exposed to drug', four by urinalysis (three and one) and three by analysis of the hair sample B (1 and 2).     

The detection of cotinine in hydrolyzed meconium samples.

To date, the screening of meconium for the determination of tobacco exposure in newborns has proven difficult. It was hypothesized that cotinine forms reversible Schiff base bonds with free amino functions on proteins, therefore, hydrolysis of meconium would be necessary for the detection of 'free' cotinine. One-hundred-and-two (102) meconium samples received into our laboratory were extracted using a routine non-hydrolysis screening procedure for drugs of abuse. Separate aliquots of the specimens were hydrolyzed and re-extracted according to the same procedure. The results of the two methods were compared using a highly specific cotinine micro-plate enzyme immunoassay procedure (EIA). Of the non-hydrolyzed samples, 33% were positive for cotinine, while 79% of the hydrolyzed samples were cotinine-positive. Common drugs of abuse did not interfere with the analysis. Micro-plate EIA provides a rapid, simple and reliable screening method for the determination of cotinine in meconium following hydrolysis and extraction. In general, the meconium specimens received into our laboratory are from newborns considered to be at risk for post-natal problems due to suspected drug and/or alcohol abuse during pregnancy.     

Results of hair analyses for drugs of abuse and comparison with self-reports and urine tests

Urine as well as head and pubic hair samples from drug abusers were analysed for opiates, cocaine and its metabolites, amphetamines, methadone and cannabinoids. Urine immunoassay results and the results of hair tests by means of gas chromatography-mass spectrometry were compared to the self-reported data of the patients in an interview protocol. With regard to the study group, opiate abuse was claimed from the majority in self-reports (89%), followed by cannabinoids (55%), cocaine (38%), and methadone (32%). Except for opiates the comparison between self-reported drug use and urinalysis at admission showed a low correlation. In contrast to urinalysis, hair tests revealed consumption in more cases. There was also a good agreement between self-reports of patients taking part in an official methadone maintenance program and urine test results concerning methadone. However, hair test results demonstrated that methadone abuse in general was under-reported by people who did not participate in a substitution program. Comparing self-reports and the results of hair analyses drug use was dramatically under-reported, especially cocaine. Cocaine hair tests appeared to be highly sensitive and specific in identifying past cocaine use even in settings of negative urine tests. In contrast to cocaine, hair lacks sensitivity as a detection agent for cannabinoids and a proof of cannabis use by means of hair analysis should include the sensitive detection of the metabolite THC carboxylic acid in the lower picogram range.     

Detection of cocaine and its metabolites in breast milk

A method was developed for measuring cocaine and its metabolites, benzoylecgonine, ecgonine methyl ester, norcocaine, ecgonine ethyl ester, cocaethylene, and m-hydroxybenzoylecgonine, in breast milk by gas chromatography/mass spectrometry. Limits of detection for this method ranged from 2.5 to 10 ng/mL, and limits of quantitation ranged from 5 to 50 ng/mL. For each of the compounds measured by this method, linear response was demonstrated to 750 ng/mL. Breast milk was collected from 11 mothers who admitted to drug use during pregnancy and ten drug-free volunteers serving as control subjects. Cocaine was detected in six of the specimens obtained from drug-exposed subjects, and in none of the drug-free control subjects. In breast milk specimens where cocaine and one or more of its metabolites were detected, the concentration of parent compound was greater than any of the metabolites. The highest cocaine concentration found was over 12 microg/mL. Breast-fed infants of cocaine abusing mothers may be exposed to significant amounts of drug orally.     

Drugs in prehistory: chemical analysis of ancient human hair

Concern about drug abuse in modern populations has led to the development of specific methods for identification of cocaine, opiates and cannabis in human hair. Drug use in prehistory can provide indirect evidence of interpopulational contact and social stratification. This paper reports drug evaluation in nineteen ancient hair samples from archaeological sites in northern Chile. Each sample was tested for the presence of traces of cocaine, opiates and cannabis, in order to establish a standard methodology for studies of drug use among prehistoric groups. Although results are negative, this absence of evidence could be due to two main causes: (1) the individuals evaluated did not use any drugs, which does not mean that other members of their cultural group did, or (2) the wide range of known drugs studied did not consider some group specific drugs, derived from local or imported plants, thus meaning that a greater drug range must be tested. In any case, our study confirms that drug testing in prehistoric samples is viable. However, in order to determine what kind of substances were used in prehistoric times new patterns that incorporate all drugs which are not part of the western pharmacopeia must be created. Finally, a methodology for the study of drug use among prehistoric groups using ancient hair samples is described.     

Practical aspects of roadside tests for administrative traffic offences in Germany

In the context of the European project ROSITA, the Institut of Legal Medicine Homburg/Saar has co-operated with the Saarland traffic police in order to assess different roadside drug tests for their functionality and reliability in traffic controls, and for their analytical force of evidence. In 254 cases within the time period from June 1999 to December 1999, police officers performed a (voluntary) roadside drug testing in saliva/sweat, or urine, to confirm or refute their initial suspicion that a driver had used drugs. Whereas in 45 cases the tests gave negative results (which were confirmed by lab urinalysis), in 209 cases the police officers ordered blood samples after a positive outcome of the tests.In 203 of the 209 positive cases, the results could be confirmed by GC/MS analysis. Regarding the prevalence of used drugs, a single consumption was found in 156 cases (113 cannabis, 38 amphetamines/methamphetamines, three opiates, two cocaine), and a consumption of two drugs was found in 44 cases (34 cannabis+amphetamines/methamphetamines, five cannabis+opiates, three cannabis + cocaine, two cocaine+amphetamines/methamphetamines). In three cases, multi-consumption was found.In six cases, the performed tests gave an incorrect prediction to the police officer at the roadside.The roadside tests gave 97.6% correct assistance to the police officers in the right direction (79.9% correct positive predictions and 17.7% correct negative predictions). As a consequence, the performed tests can be seen as a positive and needful tool for the police to get an immediate response to their initial suspicion and to take the right steps concerning a following legal action.     

Prevalence of psychoactive substances in truck drivers in the Nord-Pas-de-Calais region (France)

A previous study conducted in 1995 showed that psychoactive drug use by workers was higher in safety/security workstations than in the rest of the labour force. In order to verify this finding, we conducted a new study in 2003-2004 in the Nord-Pas-de-Calais region, restricted to truck drivers. The aim of this study was to allow harmonizing the professional practice of the occupational physicians, proposing drug prevention and drug testing policies, validating the analytical methods and the guidelines in case of positive testing results. One thousand truck drivers were studied. Urines were tested for amphetamines, cannabinoids, cocaine, opiates, benzodiazepines, buprenorphine and methadone by immunoassay. Urine ethanol determinations were performed by an ADH method. Positive urines for drugs of abuse, methadone or buprenorphine were then tested by gas chromatography or liquid chromatography coupled to mass spectrometry. Out of the 1000 drivers, cannabinoids were detected in 85 cases, opiates in 41 cases, amphetamines in 3 cases and cocaine in only one case. Buprenorphine was detected in 18 cases, methadone in 5 cases and benzodiazepines in 4 cases. Urine ethanol was positive in 50 cases. We found only one case with 6-monoacetylmorphine. Other positive opiates were metabolites of antitussives. The relatively low number of benzodiazepine positive urines could be explained by the lack of sensitivity of the test we used. All these results confirm those of the previous study for cannabinoids and ethanol in safety/security workstations. Positive results for methadone and buprenorphine are eight times higher than in the general population. In conclusion, the authors think that it will be of a great interest to test urine of truck drivers for other classes of psychoactive drugs, using a liquid chromatography-mass spectrometry method.     

The frequency of alcohol,illicit and licit drug consumption in the general driving population in South-East Hungary

In the framework of the DRUID (Driving under the Influence of Drugs, Alcohol, and Medicines) EU-6 project, a roadside survey was performed in South-East Hungary to determine the incidence of alcohol and the most frequent illicit and licit drug consumption (amphetamines, THC, illicit and medical opiates, cocaine, ketamine, benzodiazepines, zopiclone and zolpidem) in the general driving population. All 3110 drivers stopped between 01 January 2008 and 31 December 2009 were checked for alcohol, and among them 2738 persons (87.7%) participated in the further examinations, on a voluntary basis. Licit and illicit drugs were determined from their oral fluid samples by GC–MS analysis.Illicit drugs were detected in 27 cases (0.99%), licit drugs in 85 cases (3.14%), and alcohol (cut off: 0.1 g/l) was found in 4 (0.13%) cases. Illicit drug consumption was the highest among men of the ages 18–34, during the spring, and on the week-end nights. With respect to licit drugs, the highest incidence was found among women over the age of 50, during the summer, and on the week-days. All alcohol positive cases were men over the age of 35. In comparison to international European averages, the alcohol and illicit drug consumption was low, but the licit drug consumption was over the European average.     

Drug abuse's smallest victims: in utero drug exposure

The social and economic impact of drug use on our global population continues to increase leaving no geographical, social or cultural group untouched. The National Institute on Drug Abuse (NIDA), in one of the few large surveys of maternal abuse, found that 5.5% of mothers reported taking an illicit substance during gestation. These figures certainly are underestimates due to the stigma of drug use during pregnancy and the accompanying legal, ethical and economic issues. Although drugs of choice and routes of administration vary by country, exposure of our most valuable resource, our children, to the developmental effects of drugs is an enormous problem. In utero drug exposure can have a severe impact not only on the development of the fetus, but also on the child during later stages of life. More than 75% of infants exposed to drugs have major medical problems as compared to 27% of unexposed infants. The cost of treating drug-affected infants was twice the cost of non-affected infants. Obstetrical complications including placental insufficiency, miscarriage, intrauterine death, and increased incidence of infectious and sexually-transmitted diseases are higher in the drug-abusing mother. Treatment for pregnant addicts should be a high priority for our governments. Increased awareness and improvement in our understanding of drug abuse in the medical, legal and social realms will enable us to reduce the barriers to treatment for this important population.Accurate identification of in utero drug exposure has important implications for the care of the mother and child, but can raise difficult legal issues. Society discourages prenatal care with the infliction of harsh criminal penalties. Maternal drug use during pregnancy can be monitored with urine, sweat, oral fluid and/or hair testing. Detection of in utero drug exposure has traditionally been accomplished through urine testing; however, the window of detection is short, reflecting drug use for only a few days before delivery. Monitoring exposure through testing of alternative matrices, such as neonatal meconium and hair, offers advantages including non-invasive collection and detection earlier in gestation. There are many unresolved issues in monitoring in utero drug exposure that urgently require research. These can be divided into research to definitively differentiate drug exposed and non-drug-exposed fetuses, determine the most efficient methods to routinely monitor women's drug use, and determine how these drug test results relate to neonatal and maternal outcomes. Research in this area is difficult and expensive to perform, but necessary to assess accurately drug effects on the fetus. By increasing our understanding of the physiological, biochemical and behavioral effects of gestational drug exposure, we may ultimately provide solutions for better drug prevention, treatment and a reduction in the number of drug-exposed children.     

A multilevel analysis of the effect of cocaine price on cocaine use among arrestees

Using data drawn from the Arrestee Drug Abuse Monitoring Program, from the Drug Enforcement Administration's System to Retrieve Information from Drug Evidence, and from the 1990 Census, this study examined whether an arrestee's probability of testing positive for cocaine use varied across aggregate levels of cocaine price. Results from a Hierarchical Generalized Linear Modeling analysis revealed that in cities where the price of cocaine was relatively high, arrestees had a lower probability of testing positive for cocaine use. Specifically, a 10 percent increase in the price of cocaine was associated with a 3 percent decrease in the odds that an arrestee would test positive for cocaine use. Findings also showed that individuals arrested for income-generating crimes did not have a higher probability of testing positive for cocaine when the price of cocaine was relatively high. Thus, it appeared that higher cocaine prices were not inducing users to amplify their criminal activity in order to finance a more costly drug addiction. Finally, results failed to furnish support for the hypothesis that individuals substituted opiates or marijuana when cocaine became more expensive.     

Use of MDA (the "love drug") and methamphetamine in Toronto by unsuspecting users of ecstasy (MDMA)

It has recently been reported that purity of illicit tablets of ecstasy (MDMA) is now high. Our objective was to confirm whether hair of drug users, who request only ecstasy from their supplier, contains MDMA in the absence of other drugs. GC-MS analysis of scalp hair segments disclosed the presence of MDMA in 19 of 21 subjects and amphetamine/methamphetamine in eight subjects. Surprisingly, seven subjects had hair levels of the MDMA metabolite, MDA, equal to or greater than those of MDMA, suggesting use of MDA in addition to that of MDMA. These amphetamine derivatives might be included by clandestine laboratories to enhance effects of the drug cocktail or because of a perception that MDA synthesis might be simpler than that of MDMA. Drug users and investigators examining possible brain neurotoxic effects of MDMA need to consider that "ecstasy" tablets can contain MDA and methamphetamine despite no demand for the drugs.     

Evaluation of the Cozart RapiScan drug test system for opiates and cocaine in oral fluid

The purpose of this study was to evaluate the efficiency of the Cozart RapiScan (CRS) drug test system for detecting opiates and cocaine in oral fluid. Oral fluid samples were collected using the Cozart RapiScan collection system from 358 donors who were receiving treatment for their addiction and were monitored for drug misuse. A further 103 oral fluid samples were collected from volunteer donors who were not drug users. The samples were analyzed in the laboratory using the two-panel Cozart RapiScan cartridge for opiates and cocaine and confirmed using gas chromatography-mass spectrometry (GC-MS). The samples were stored frozen at -20 degrees C until analysis by GC-MS. The overall accuracy of the CRS for both opiates and cocaine was 100%. Samples spiked at 50% above and below the cut-off consistently gave negative and positive results respectively. A total of 88 samples were positive for various opiates and 111 samples were positive for cocaine and/or its metabolites. The CRS for opiates and cocaine in oral fluid, using a cut-off of 30 ng/mL morphine or benzoylecgonine equivalents in neat oral fluid, had overall efficiencies of 98% and 99%, respectively, versus GC-MS. A series of potential adulterants of oral fluid were evaluated and shown not to alter the outcome of the test result.     

Comparison of point-of-collection screening of drugs of abuse in oral fluid with a laboratory-based urine screen.

Oral fluid is becoming increasingly useful for the detection of drugs, since it is a non-invasive specimen to collect and, because collection is directly observed, it is difficult to adulterate. A point-of-collection (POCT) oral fluid drug analysis kit has been developed for use in many drug testing situations. This paper summarizes the results of field evaluations of the ORALscreen System for screening of drugs in oral fluid. The ORALscreen System consists of an oral fluid collection device and a test device containing a lateral flow membrane immunoassay system. Paired samples (oral fluid and urine) were collected from drug users and the results from the ORALscreen POCT system were compared to urine screening results conducted in a licensed laboratory. The results demonstrate that the ORALscreen System has excellent percent agreement with the laboratory-based urine screening test results for the detection of cocaine and opiates through 2.5-3 days following drug use, respectively. Tetrahydrocannabinol (THC) was detected by ORALscreen on the day of use and 1 day after use. Good correlation between urine and oral fluid screening results was observed for the methamphetamine positive samples; however, the number of days following drug use was not determined.     

Classical stimulants in Dallas County: A retrospective review of toxicological,seized drug,and demographical data from 2017 to 2022

Cocaine and methamphetamine remain highly abused drugs in the United States due to their euphoric effects. This study examines classical stimulant casework, defined as cases positive for methamphetamine and/or cocaine, received by the Toxicology Laboratory and the Drug Analysis Laboratory at the Dallas County Southwestern Institute of Forensic Sciences from local law enforcement agencies and/or the Office of the Medical Examiner (OME) between January 1, 2017, and December 31, 2022. Methamphetamine positivity increased from 10.4% to 20.3% in the Toxicology Laboratory over the 6 years, whereas cocaine positivity remained relatively stable at approximately 17%. Similarly, in the Drug Analysis Laboratory, the methamphetamine positivity rate changed from 24.8% to 33.2%, whereas cocaine identification remained stable at approximately 20%. Blood concentrations of methamphetamine in OME cases ranged from 10.1–42,740.0 ng/mL while they were lower in DWI casework ranging from 10.2–2385.0 ng/mL. The blood concentration trends of cocaine were similar to methamphetamine, with OME casework ranging higher (10.0–24,501.0 ng/mL) than DWI casework (10.2–371.6 ng/mL). Polydrug use was evident for both methamphetamine and cocaine in postmortem cases, and the top three most frequently co-occurring drug/drug class were opioids/opiates, cannabinoids, and ethanol. The results from this study aid in the understanding of historical usage trends of cocaine and methamphetamine in Dallas County and how those trends have changed over time as newer stimulant drugs have emerged.     

Comparison of drug abuse in different military populations

Quantitative analytical data, generated at the Navy Drug Screening Laboratory, Great Lakes, Illinois, expressed as percent confirmed positives for four drugs of abuse (marijuana metabolite, cocaine metabolite, amphetamines, and opiates) are summarized and compared according to their population of origin. The four populations of interest included U.S. Navy and Marine Corps recruits and service school members. Conformed positive urines for marijuana showed a small but significant decline (p less than 0.001) from about 1.2% confirmed positive among U.S. Navy recruits entering service school commands in 1984 to 0.9% among Navy service school members in 1988 and from 2.0% among U.S. Marine Corps recruits entering service schools in 1984 to 0.8% among Marine Corps service school members in 1988. Navy and Marine Corps recruits showed a significantly higher (p less than 0.001) confirmed positive use rate (6.1 and 3.3%, respectively) compared to service school members, perhaps reflecting their recent civilian use pattern. The relatively high confirmed positive cocaine rate among all groups may have reflected an increasing trend in all populations, confirming a similar trend in high school and other civilian populations. Generally, the frequency of confirmed positive urines with amphetamines and opiates, based upon the findings at the Navy Drug Screening Laboratory at Great Lakes, has been static except for an apparent recent increase in amphetamine use in 1988. The decline in confirmed positive drug urinalyses among service school members from both the Navy and Marine Corps indicated that perhaps education and maturity had a positive effect upon their behavior.