Administer the Structured Clinical Interview for DSM-IV
Several self-report scales assess substance dependence and substance abuse symptoms, but none assesses specifically for marijuana. Identification of cannabis use disorders is accomplished most reliably using a structured interview to assess diagnostic criteria. The Structured Clinical Interview for DSM-IV (SCID-IV) (form AS4) used in this manual has been adapted for clients who use marijuana (First et al. 1996). A typical structured interview starts with objective questions to obtain a brief history of the client’s substance use and proceeds through a series of questions that assess for the presence of DSM-IV diagnostic criteria for dependence (questions 1 through 7) and abuse (questions 8 through 11). Each objective question can be followed by open-ended prompts to elicit information relevant to the symptom being assessed.
The counselor asks the client each SCID-IV question and circles the appropriate clinical rating for the response. If the counselor is convinced that a particular symptom is present, he or she should not allow a client’s denial of the symptom to go unchallenged. In rare cases, an item may be rated as present even when the client steadfastly denies it. It is not necessary for the client to agree that the symptom is present. The counselor uses all sources of information, including the forms completed in the TLFB process, to determine the appropriate rating for the client in response to SCID-IV questions. In some cases, the counselor may need to explore discrepancies between the client’s account and other sources of information. Form AS4 provides additional instructions for completing the SCID-IV.
Information for Assessing Cannabis Dependence Criteria
To administer the SCID-IV and assess for the presence of each symptom, it is important to understand the intent of substance use disorder criteria and the ways in which symptoms can be manifested in people who use marijuana.
Tolerance. Tolerance refers to needing more or higher quality marijuana to get high than when the client first began using it (DSM-IV symptom 1 in exhibit IV-1; SCID-IV question 6, Have you found that you need to use a lot more or higher quality marijuana to get high than you did when you first started using it regularly?). This symptom reflects the body’s adaptation to or compensation for the chronic presence of marijuana, and it may predict the development of withdrawal symptoms if use continues. To determine tolerance level, the counselor asks the client to compare the current effects of marijuana with past effects.
According to DSM-IV, the client must use at least 50 percent more marijuana than when he or she first started using to meet the tolerance criterion, so it is important to ask the client to quantify how much more is used now to achieve the same effect compared with when he or she began to smoke regularly. The tolerance criterion can be met if the client reports markedly diminished effects from the same amount of marijuana that used to get him or her high.
Withdrawal. Withdrawal symptoms associated with cessation of cannabis use are another indication that the body has made physiological adaptations to the presence of cannabinoids and may motivate the person to continue using (DSM-IV symptom 2 in exhibit IV-1; SCID-IV question 7, In the past month, have you had withdrawal symptoms? Have you felt sick when you cut down or stopped using? Or after not using for a few hours or more, have you smoked to keep from getting sick?).
Although a cannabis withdrawal syndrome is not described in DSM-IV, symptoms associated with marijuana cessation have been documented in several studies. Withdrawal symptoms can include
• Appetite disturbance
• Sleep disturbance (e.g., vivid dreams)
• Night sweats
• Headaches
• Nausea
• Irritability
• Restlessness
In general, when withdrawal symptoms occur, they are present for a short period (i.e., a few days to 2 weeks). It is not known to what extent these symptoms motivate continued use of marijuana or whether they play a clinically meaningful role in the process of modifying marijuana use.
However, more than half the clients presenting for treatment report experiencing some withdrawal symptoms or continuing to use marijuana to avoid withdrawal symptoms. The counselor asks the client about the occurrence of withdrawal symptoms when he or she has cut down or stopped using and whether he or she used marijuana to avoid withdrawal symptoms. If the client acknowledges either experience, then the criterion for this symptom is met.
Impaired control. To assess impaired control over use, the counselor asks whether the client often ended up smoking more than was intended and whether he or she sometimes smoked for a longer period than was intended (DSM-IV symptom 3 in exhibit IV-1; SCID-IV question 1, In the past month, have you found that, when you started using marijuana, you ended up smoking much more of it than you were planning to? or Have you used it over a much longer period than you were planning to?; an affirmative answer to either question should lead the counselor to inquire about specific instances and the circumstances leading to overuse). The repeated failure to terminate marijuana use as planned is evidence of impaired control.
Impaired control over marijuana use also is assessed by asking whether the client has made repeated unsuccessful attempts to quit or reduce use or has had a persistent desire to do so (DSM-IV symptom 4 in exhibit IV-1; SCID-IV question 2, In the past month, have you tried to cut down or stop using marijuana? or Did you ever stop using altogether?). Typically, these attempts include self-imposed rules or other strategies to avoid marijuana entirely or to limit the frequency of use. It is useful to ask specifically about the number of times the client has attempted to cut down during the period being assessed and whether these attempts were because of concern about the extent of use. Resumption of marijuana use after seeking professional help or joining a mutual-help group (e.g., Narcotics Anonymous) is evidence of lack of success. These experiences suggest impairment in control. If the client denies any attempts at reducing marijuana use, the counselor asks specifically whether he or she would like to stop or reduce use but has not done so for some reason. Evidence of impaired control includes the client’s wanting to stop or reduce use but not making an attempt because he or she knew that the attempt would be unsuccessful.
Salience. An important aspect of dependence relates to the primacy of the substance in a person’s life. The salience of marijuana is investigated by asking the client about how much time he or she spends obtaining it, using it, and recovering from its effects (DSM-IV symptom 5 in exhibit IV-1; SCID-IV question 3, In the past month, did you spend a lot of time using marijuana or doing whatever you had to do to get it?). The phrase “a lot of time” is not defined precisely, but it often becomes clear that marijuana-related activities occupy an excessive amount of time. For instance, if the client is intoxicated on marijuana most of the day, most days of the week, for a month or more, then salience is apparent. At other times, the counselor determines the appropriateness of the amount of time given to marijuana-related activities. If marijuana use is confined to recreational times of the day or week, this symptom may not be present.
Another determinant of the salience of marijuana can be when the client reports that he or she has given up or reduced involvement in important social, occupational, or recreational activities because of marijuana use (DSM-IV symptom 6 in exhibit IV-1; SCID-IV question 4, In the past month, did you use marijuana so often that you used it instead of working or spending time on hobbies or with your family or friends?; a yes response to this question indicates that marijuana use has a higher priority than activities such as work or spending time with friends or family, hobbies, or exercising.) This breakdown in the normal processes of social control is an indication of dependence on the drug.
The persistence of marijuana use despite knowledge that it causes or exacerbates psychological or physical problems is an indication of either the salience of the drug or impaired control over its use (DSM-IV symptom 7, exhibit IV-1; SCID-IV question 5, Do you forget things or have trouble concentrating? Are you anxious or sad a lot? Has marijuana caused you physical problems such as difficulty breathing, many colds, or a chronic cough? Has it made a physical problem worse?). The counselor assesses whether marijuana use leads to problems with motivation, depression, anxiety, concentration, memory, or other psychological problems. Similarly, the client’s awareness about the effect of marijuana use on breathing, chronic cough, or other physical conditions is ascertained. If the client acknowledges a relationship between marijuana use and any of these physical or psychological problems but continues to use anyway, marijuana use may have a higher priority than his or her health or the client may be unable to limit use effectively.
Diagnosing cannabis dependence. To complete the diagnosis, the counselor counts the number of dependence symptoms that are present, that is, questions 1 through 7 on the SCID-IV that receive a rating of 3. If three or more questions have a rating of 3, the client meets DSM-IV criteria for cannabis dependence. In general, the dependence syndrome occurs on a continuum, so more symptoms indicate greater severity of dependence. Even when the client does not meet the criteria fully, the counselor should discuss symptoms that signal the beginning of a potential disorder and the level of impairment associated with the symptoms.
Information for Assessing Cannabis Abuse Criteria
In the absence of cannabis dependence, the counselor assesses recurrent negative consequences associated with marijuana to diagnose cannabis abuse. The counselor inquires about missed days at school or work related to marijuana use and asks whether marijuana has affected the client’s abilities at school or on the job (DSM-IV symptom 1 in exhibit IV-2; SCID-IV question 8, In the past month, have you missed work or school because you were high or hung over? How often did this occur?). It may be appropriate to ask whether marijuana has interfered with keeping the house clean or taking care of children.
Other examples of abuse are driving when feeling high or engaging in other dangerous activities when under the influence of marijuana (DSM-IV symptom 2 in exhibit IV-2; SCID-IV question 9, n the past month, did you use marijuana in situations in which it might have been dangerous?), experiencing legal problems (DMS-IV symptom 3 in exhibit IV-2; SCID-IV question 10, Has your use of marijuana gotten you into trouble with the law in the past month), and continuing use despite awareness that use causes problems with friends, family, or co-workers (DSM-IV symptom 4 in exhibit IV-2; SCID-IV question 11, Has your use of marijuana caused you problems with other people, such as with family members, friends, or people at work? Have you gotten into physical fights or had bad arguments about your marijuana use?).
Diagnosing cannabis abuse. For a cannabis abuse diagnosis, at least one of the symptoms described above must have occurred two or more times during the period being assessed. More information is available in First and colleagues (1996, 2000).