Introduction Marijuana is the most widely used illicit drug in the Western world and the third most commonly used recreational drug after alcohol and tobacco. According to the World Health Organization, it also is the illicit substance most widely cultivated, trafficked, and used.
Although the long-term clinical outcome of marijuana use disorder may be less severe than other commonly used substances, it is by no means a "safe" drug. Sustained marijuana use can have negative impacts on the brain as well as the body so it is important to look at ways to detect the presence of substance use. Screening procedures are designed to detect the possible presence of a substance use disorder and the need for further care. This second part course of Marijuana And Substance Use Disorder will focus on the screening and treatment of marijuana use and addiction using DSM-5 criteria and evidenced-based screening tools and guidelines relied upon to develop a plan for recovery.
Screening For Marijuana Use Screening refers to methods and procedures, often of a brief nature, designed to rule out the possibility of substance use problems. Screening is not the same thing as providing a diagnosis (determining if one meets criteria as established in a diagnostic manual) or evaluation (a more thorough analysis of substance use problems, of which screening is but one component). Screening procedures are designed to detect the possible presence of a substance use issue and the need for further care. In general, screening methods can be informal and observational or more formal with the use of brief screening instruments.83 Once a clinician detects substance use and addiction to marijuana, treatment plans are developed to stop the patient’s marijuana use.
Screening Methods and Procedures
Screening consists of comparing substance disorder criteria — that is, the concept defining harmful use — against the actual pattern of use. This process can provide a variety of insights on the side of both the practitioner and patient, which are open to diverse interpretation. Thus, it is crucial to design screening tools that adequately reflect the criteria defining problematic use, and those that ensure that responses are accurate, valid and actionable.
It is important to note that the following is a list of general screening and observation procedures. These categories, and their associated criteria, are adjusted to assess for specific substance disorders. For example, when marijuana use disorder is suspected the screening process will not include observations for track marks.
The DSM-V Criteria in Screening
Harmful use criteria can differ from one population to another. For example, the DSM-V does not completely fit adolescents. Within DSM-V, criteria applicable to adolescents are often absent for concepts such as withdrawal, tolerance or giving up other activities providing pleasure and interest. Thus, it has been argued that DSM-V concepts, when applied without adaptation to adolescents, do not deliver the prognostic value they have for adults. According to many researchers, current tools made for the screening of adults only deliver a late screening of youth-specific problems. So, it has become common for research teams working with adolescents to try to develop their own tools.
Standard marijuana screening tests are generally too long to apply as part of a general population survey. The application of such instruments requires more time than available in most cases in population surveys, and sometimes by skilled interviewers. They have only been tested in clinical populations, which might not be sufficient to assess their applicability in the general population. However, they do have some merit and are worth discussing. The following table provides an overview of the most common screening tests.74
Cannabis Problems Questionnaire (CPQ)
The Cannabis Problems Questionnaire (CPQ) was very recently modeled (Copeland et al., 2005; Martin et al., 2006) on the 46 items of the Alcohol Problems Questionnaire (APQ) (Williams and Drummond, 1994). The study was conducted among 72 adolescents smoking at least 15 days per month. It left the final CPQ as a 22-binary-item scale, which seems to be an efficient and reliable measure of cannabis-related problems for use with populations of current cannabis users, offering more than 80% sensitivity and specificity according to DSM IV criteria.
Marijuana Craving Questionnaire (MCQ)
Heishman et al., (2001) have developed and validated the Marijuana Craving Questionnaire (MCQ), a 47-item multidimensional questionnaire on marijuana craving, based on the model of the Questionnaire on Smoking Urges (Tiffany and Drobes, Chapter 2 p.41, 1991) and the Cocaine Craving Questionnaire (Tiffany et al., 1993). In their study, current marijuana smokers (n = 217) not seeking treatment had completed forms assessing demographics, drug use history, marijuana quit attempts and current mood. The findings suggested that four specific constructs characterize craving for marijuana, which are reviewed as follows:
Emotionality — use of marijuana in anticipation of relief from withdrawal or negative mood;
Expectancy — anticipation of positive outcomes from smoking marijuana;
Purposefulness — intention and planning to use marijuana for positive outcomes.
Heishman, et al., (2001) found that the MCQ is a valid and reliable instrument for assessing marijuana craving in individuals not seeking drug use treatment, and that marijuana craving can be measured in the absence of withdrawal symptoms.
Marijuana Effect Expectancy Questionnaire (MEEQ)
The Marijuana Effect Expectancy Questionnaire (MEEQ) assesses motivation to use marijuana (Schafer and Brown, 1991). It has 70 yes/no format items with agree/ disagree instructions similar to those of the Alcohol Expectancy Questionnaire (AEQ). Subjects are asked to respond according to their own beliefs and whether they have actually used marijuana. Although MEEQ is not designed for general clinical screening, it contains items with potential for screening. It has been tested in a psychometric evaluation on 279 adolescents from a clinical and community sample and on 149 males from a clinical sample.
Marijuana Screening Inventory
The Marijuana Screening Inventory (MSI-X) is a 39-binary-item scale. Thirty-one of the items are used to calculate a simple score to classify into one of the four following categories: no problem; normal or experimental marijuana use; potentially problematic marijuana use; and problematic marijuana use. The study was conducted on a sample of 420 military reservists (a convenience sample). The MSI-X was found to be promising, especially for rapid diagnosis assessment, but a clinical validation is yet to be conducted.
Screening typically occurs via a diagnostic or intake interview. If the client reports a problem in a specific area, the clinician has the option to focus on this by asking more specific questions related to the substance problem. Screening also occurs through observation of the client’s immediate signs and symptoms as well as his or her behavior outside the counseling setting, including past history.75 Part of screening is addressing and exploring the red flags that provide clues as to what role, if any, drug use plays in the client’s life. These red flags become even more important when the client is not forthcoming about his or her substance use at the beginning of the screening. In general, observational red flags fall into three categories: physiological, psychological, and behavioral.
A brief inquiry into typical physiological issues or general medical conditions can sometimes point to the extent of possible substance use problems. Liver problems, hypertension, ulcers, tremors, or injection track marks are indications of severe use. For clients who do not immediately admit to use but are still using problematically, these and other physiological symptoms can tip off the clinician that problematic substance use is a possibility and needs further exploration.
An additional area of exploration, although not directly about current physiological symptoms, is the client’s potential genetic predisposition. Inquiry about family history of substance use provides additional insights to help clarify the assessment and diagnostic picture. For example, a client who suggests that he or she has a drink now and then, but insists drinking is not a problem, may report that a mother and father were “alcoholics” and that the father used other substances as well. In this case, the possible genetic link to alcohol use would warrant further and more targeted substance use assessment, especially if the client reports some negative consequences as a result of the person’s substance use.
Many clients report symptoms of depression, anxiety, or other emotional problems and use substances to self-medicate or cope. Indeed, psychological symptoms, such as depression and anxiety, are often associated with problematic substance use. Also associated with use are negative or difficult emotions such as guilt, shame, anger, or boredom. At minimum, practitioners should check in with clients who report severe negative emotions related to their substance use history, current behavior, and typical methods of coping.
There are many behavioral signs of substance use and addiction, some of which are obvious (i.e., evidence of intoxication), and some of which are indirectly related (i.e., work problems). Perhaps the most important area of inquiry is if there has been any past treatment for substance-related problems. Clients who affirm previous attempts at treatment to address substance-related problems often struggle currently with those same problems. Additional behavioral problems often associated with substance use include legal problems, poor work history, financial problems, extreme talkativeness, poor judgment, erratic behavior, frequent falls, increase in risk taking, and frequent hospitalizations. One or more of these behavioral issues should alert the clinician to the possibility of significant substance use.76
An effective addition to self-report screening instruments is biological lab tests designed to detect the presence of substances. Typically, biological drug screens occur by sampling via urinalysis and hair analysis but there are other methods as well. These tests may be most useful to corroborate self-report data, especially when there is high suspicion that one is not being honest about his or her substance use.77 Some agencies or substance use programs require random screens, particularly when medication is used as part of the addiction treatment. Clinicians, however, may not have the ability to screen for recent drug use within their agency. In these instances, the clinician will utilize a referral list of medical specialists who are trained to perform biologically based substance use screening.78
It is important to know that biologically based screens are not a substitute for self-report data. Biological screening tests tend to have low sensitivity (producing a high false positive rate) and are impacted by one’s age, gender, smoking status, metabolism, how the drug was taken, how long ago the drug was ingested, and the drug’s potency.79 They are best used as one piece of the screening process and in conjunction with self-report data. If possible, the clinician should utilize all available resources in the screening process, such as well-established screening instruments, biological measures, intake interviews, and collateral reports.80 Blood Testing for Marijuana
There is very active interest in testing urine for the presence of marijuana. The standard urine drug screen will cover a range of different drugs. The urine test can detect marijuana for days or weeks after use and detect the non-psychoactive marijuana metabolite THC-COOH. THC-COOH has an unusually long elimination time (days to weeks), so that the urine test is considered to be more sensitive to marijuana.
Hair and Saliva Testing:
It is possible to detect marijuana and its metabolites in other tissues besides blood. At present there is great interest in hair and saliva analysis. To date, methods for the detection of THC in hair have been somewhat problematic, but there seems to be progress in this area. The relationship between blood and saliva concentrations has been poorly studied. Only two systematically controlled studies have addressed the relationship.
Although great effort has gone into developing methods for the detection of THC in saliva (toxicologists tend to refer to saliva as “oral fluid,” acknowledging that saliva contains many cellular components), and a number of devices have come to market, the results are not particularly encouraging. The oral kinetics of THC is not understood well enough to use for forensic purposes.
Results with hair testing are much more encouraging, and it may even be possible to quantitate, not just detect, long-term use. In one recent study of 22 healthy men, hair samples from 12 chronic marijuana users (average age 22 ± 2 years) were compared to those obtained from 10 non-users, and detailed histories of their drug-use pattern were obtained; average cannabis usage ranged from 0.25 to 2.5 g/day (mean ± SD: 0.74 ± 0.60 g/day). Most of the subjects had smoked at least every 2 days for the past year. Concentrations of δ-9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN) were measured in the hair of each subject. In every one of the users, concentrations of all three metabolites were detected in the hair and there was an increase in the concentration of all major cannabinoids in hair proportionate to the amount consumed. The more marijuana smoked, the higher the concentration of marijuana and its metabolites found in the hair. Hair color and hair treatments had no effect on the outcome. Both the reported cumulative cannabis dose during the last 3 months and the cannabis use during the last 3 months — estimated from the daily dose and the frequency per year — were more closely related to the sum of THC, CBN, and CBD concentrations rather than to the THC content alone.81
Testing Fat Tissue for Marijuana Use
Because of marijuana’s very great steady state volume of distribution, it can be recovered from many tissues. One study, published nearly 20 years ago, analyzed THC concentrations in fat samples obtained from heavy marijuana users one week before and four weeks after smoking. The concentration of δ-THC in these samples ranged between 0.4 and 193 ng/g wet tissue. While fat biopsies are unlikely to become routine forensic tests, they provide an alternative method to screen for marijuana use.
Detection Times for Screening Tests
Some metabolites of the THC, a number of which may still be active in the system, can be detected in the body at least 30 days following ingestion of a single dose and in the urine for several weeks following chronic use. In one reported study researchers collected urine from seven healthy volunteers (ages 20– 35 years, four male), all chronic cannabis users, during enforced abstinence on a locked ward and for up to 29 days. All of the subjects were regular marijuana smokers who reported smoking one to five “blunts” (marijuana rolled into a tobacco leaf which results in the appearance of a cigar) per day. Urine specimens collected during their confinement was analyzed, using a method that had a 2.5 ng/mL limit of quantification. The minimum time until the urine was cleared of 11-OH-THC ranged from 7.56 to 29.8 days, with concentrations ranging from 25 to 133 ng/mL. Maximum urinary concentrations of the other metabolite, THCCOOH, fell into the same time range as 11-OH-THC. In federally regulated workplace testing, a 15 ng/mL cutoff is mandated for workplace drug testing, and the volunteers studied above would have been considered active marijuana smokers even though they had not smoked for more than one week.
Similar results have been observed with plasma measurement. Twenty-eight self reported daily marijuana smokers (ages 19 to 36 years, approximately equal numbers of men and women, and 84% African American) underwent enforced abstinence in a locked ward. Plasma specimens were collected when the volunteers arrived on the locked ward and then daily. After not smoking marijuana for 16 hours, 93% of the participants were still positive for the drug (THC > 0.25 ng/mL — the minimum level of detection). On the seventh day of observed abstinence, half of the participants continued to test positive for THC, and four of these individuals had levels > 2.0 ng/mL, the value that is usually considered proof of recent use by the European Union and some U.S. states. The median THCCOOH concentration in this group was 11.5 ng/mL after one week’s abstinence.
The above study results suggested that the detection of THC in plasma is a dubious forensic value because it does not reliably differentiate between acute and chronic use. This observation is almost certainly explained by the accumulation of THC in deep tissue compartments with gradual release of THC from tissue stores into the bloodstream. It has been found in alive individuals that the detection of low THC concentrations does not reliably identify recent use.8,9,13
Collateral Interviews: Family and Friends
Given the prevalence of denial on the part of substance users, if there is any suspicion about a possible substance use problem, it is important in the first interview to request permission to involve family members, friends, coworkers, and others who may be able to provide more objective information about the client’s pattern of substance use and related behaviors. Collateral interviews often help to give a more complete picture of both the user and the impact they are having on others in their environment. Partners and family members of substance users often want to be helpful in the affected individual’s treatment.
If either a substance user or family member is describing examples of domestic violence, legal problems, financial problems, medical complications, or other issues that are often related to substance use, it is important to determine if they think the problem would have occurred if drugs were not a factor.82 Questions for family members include:83
Does the user’s personality change while using?
Has anyone been concerned or embarrassed about the use?
Have you or others been uncomfortable about your safety in circumstances such as riding in a car when the user has been driving after using drugs?
It is important to note that family members and significant others may be unaware of, or reluctant to divulge, information about the client’s substance use patterns. Like the client, they are often experiencing denial or avoiding a confrontation with the user. Common misinformation about substance use may divert the focus of the problem to other factors that are then presented as the primary problem.84 Due to the shame and embarrassment that frequently accompany the admission of substance use, the clinician may need to reassure everyone involved in the assessment that appropriate help can only be made available if an understanding of the problem is accurate and complete.
The most important aspect of any assessment of substance use is the diagnostic interview. A carefully planned and conducted interview is the cornerstone of the diagnostic process. The initial contact with someone for the assessment of substance use may occur within the context of individual, family, group, or marital counseling. The clinician may be aware of the possible problem by the nature of the referral, or it may be discovered within the context of a family or marital problem. Referrals from physicians, other clinicians, or the legal system may be clearly defined as a referral for the purpose of assessing a drug or alcohol problem. Many assessments, however, will initially be undertaken as a part of a clinician’s normal interviewing procedure.
A routine clinical interview should include questions about a client’s habits of using prescription drugs and/or illicit drugs, alcohol, tobacco, and caffeine. An important part of the diagnostic interview is an assessment of the client’s readiness for change. The transtheoretical model offers clinicians very useful guidelines and information to assist in evaluating where the client is in the process of change. This model describes a series of six stages people experience in making changes, whether the changes are in therapy or not: 1) precontemplation, 2) contemplation, 3) determination, 4) action, 5) maintenance, and 6) relapse. By determining the stage that the client is in, therapists can focus treatment on helping that client proceed through the various stages of change.85
The transtheoretical model has been incorporated into the principles of motivational interviewing with substance use clients. It elaborates on targeting specific questions and responses to the stages of change, which can be very helpful in the process of diagnostic interviewing. A clinical interview that incorporates motivational interviewing techniques sets the stage for a successful counseling relationship and helps with treatment planning. Therapists who plan to work with clients that have a substance use disorder benefit greatly from familiarity with the model and techniques of interviewing.86
Given the frequency of denial and minimization encountered with clients who are experiencing substance use problems, having a supportive, respectful, effective strategy for interviewing is essential. Initially, it is still important to ask the client directly about his or her use of drugs or alcohol. Many clinicians find it helpful to assure the client that they are not asking questions about substance use in order to make judgments.87 People will often respond less defensively if they are reassured that the clinician is trying to determine the impact of drugs and alcohol on the patient’s life, rather than trying to determine if he or she is an addict. If either a substance user or family member is describing examples of domestic violence, legal problems, financial problems, medical complications, or other issues that are often related to substance use, it is important to determine if they think the problem would have occurred if alcohol or drugs were not a factor.82
An interview format that gathers information specific to substance use should be a standard part of the assessment process. An example of a structured interview format is the Substance Use History Questionnaire. It may be given to the client to complete, or the questions can be asked during the interview. The information from this procedure will help in determining what additional assessment instruments to use. Information regarding work habits, social and professional relationships, medical history, and previous psychiatric history are also necessary for the assessment. Questions related to each of these areas should be included as a part of the standard intake interview.88