eMedicine Specialties > Psychiatry > Addiction

Cannabis Compound Abuse: Differential Diagnoses & Workup

Author: Lina Cassandra Vawter, MD, Resident, Department of Psychiatry, University of Massachusetts Memorial Medical Center
Coauthor(s): Caroline Fisher, MD, PhD, Associate Director of Psychiatric Education & Training, Assistant Professor of Psychiatry, Consulting Staff in Pediatric Neurology, Department of Psychiatry, University of Massachusetts Medical School; Medical Director and Co-owner, Pediatric Behavioral Health, LLC
Contributor Information and Disclosures

Updated: Feb 20, 2007

Differential Diagnoses

Alcohol-Related Psychosis
Hallucinogens
Allergic and Environmental Asthma
Panic Disorder
Amphetamine-Related Psychiatric Disorders
Primary Hypersomnia
Anxiety Disorders
Sedative, Hypnotic, Anxiolytic Use Disorders
Atrial Tachycardia
Substance-Induced Mood Disorders: Depression and Mania
Brief Psychotic Disorder
Toxicity, Benzodiazepine
Delirium
Depression

Workup

Laboratory Studies

  • Cannabinoids can be detected in the urine for as many as 21 days after use in persons chronically using marijuana because these lipid soluble metabolites are slowly released from fat cells into the blood; however, 1-5 days is the normal urine-positive period.
    • The primary method for urinalysis detection is enzyme immunoassay or radioimmunoassay. This method is inexpensive, quick, and accurate.
    • This is also useful for confirmation of abstinence.
    • Urine samples are difficult to obtain from people who are addicted, and providing a urine sample is easily evaded. Urine toxicology testing should be performed under supervised conditions to ensure reliability of results.
    • Gas chromatography (GC) in combination with mass spectrometry (MS) and/or thin-layer chromatography (TLC) is used to confirm positive results, especially in legal proceedings.
    • With all types of tests mentioned, including TLC, false-negative results tend to be more common than false-positive results.
  • Blood samples may be used to measure quantitative levels of cannabinoids.
    • Serial monitoring of THC-COOH to creatinine ratios can distinguish between recent use and residual excretion.
    • To assess the extent of cannabis use, determination of free and bound THC-COOH can be useful.
    • Blood analysis is the preferred method of detection for interpretation of acute effects. The cannabis influence factor (CIF) is a tool that is used to interpret concentrations of THC and its metabolites in forensic cases. Absolute driving inability has been proposed in the case of CIF of 10 or higher. The higher the CIF, the more recent the cannabis abuse.
    • Blood samples must be taken within a prescribed 8-day period, and THC-COOH concentration greater than 75 ng/mL is associated with regular consumption of cannabis. THC-COOH concentration less than 5 ng/mL is associated with occasional consumption.
  • Hair analysis is not a sensitive enough tool to detect cannabinoids.
    • THC, and the main metabolite THC-COOH, do not incorporate to a great extent into hair. TCH-COOH is not highly bound to melanin. Hence, concentrations in hair are much lower when compared with other drugs of abuse.
    • Since TCH is present in cannabis smoke, it can also be incorporated into hair simply by second-hand exposure.
  • Saliva testing is a newer technology for detection
    • The presence of delta-9-THC in oral fluid is a better indication of recent use than the presence of 11-nor-delta-9-THC-9-COOH that is detected in urine. Therefore, the probability that a user is experiencing effects is higher.
    • This may prove especially useful in the monitoring of driving while under the influence.

Imaging Studies

  • While no confirmatory imaging study exists for marijuana use, pilot investigations involving neuroimaging of marijuana smokers performing various mental tasks have revealed many differences in comparative levels of activity in many regions of the brain with respect to controls.
  • Functional MRI (fMRI) and diffusion tensor imaging (DTI) techniques demonstrate significant differences in the magnitude and pattern of signal intensity change within the anterior cingulate and the dorsolateral prefrontal cortex while performing standardized tasks in chronic marijuana smokers compared with healthy controls.
  • Neuroimaging studies, such as CT scanning, MRI, and positron emission tomography (PET) scans, are extensively used to study the neurobiological effects of cannabis abuse but are not clinically useful in the definitive determination of recent abuse.

More on Cannabis Compound Abuse

Overview: Cannabis Compound Abuse
Differential Diagnoses & Workup: Cannabis Compound Abuse
Treatment & Medication: Cannabis Compound Abuse
Follow-up: Cannabis Compound Abuse
Multimedia: Cannabis Compound Abuse
References
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References

  1. Substance Abuse and Mental Health Services Administration. Results from the 2005 National Survey on Drug Use and Health: National Findings. Rockville, MD: Office of Applied Studies, NSDUH Series H-30;. 2006;DHHS Publication No. SMA 06-4194.

  2. Johnston LD, O'Malley PM, Bachman JG, Schulenberg JE. Monitoring the Future national results on adolescent drug use: Overview of key findings, 2005. Bethesday, MD: National Institute on Drug Abuse;. 2006;NIH Publication No. 06-5882.

  3. Agrawal A, Lynskey MT. The genetic epidemiology of cannabis use, abuse and dependence. Addiction. Jun 2006;101(6):801-12.

  4. Degenhardt L, Hall W. Is cannabis use a contributory cause of psychosis?. Can J Psychiatry. Aug 2006;51(9):556-65.

  5. Gruber SA, Yurgelun-Todd DA. Neuroimaging of marijuana smokers during inhibitory processing: a pilot investigation. Brain Res Cogn Brain Res. Apr 2005;23(1):107-18.

  6. Haney M, Rabkin J, Gincerson E, Foltin RW. Dronabinol and marijuana in HIV+ marijuana smokers: acute effects on caloric intake and mood. Psychopharmacology. 2005;181(1):170-178.

  7. Hurd YL, Wang X, Anderson V, et al. Marijuana impairs growth in mid-gestation fetuses. Neurotoxicol Teratol. Mar-Apr 2005;27(2):221-9.

  8. Iversen L. Cannabis and the brain. Brain. Jun 2003;126(Pt 6):1252-70.

  9. Musshoff F, Madea B. Review of biologic matrices (urine, blood, hair) as indicators of recent or ongoing cannabis use. Ther. Drug Monit. 2006;28:155-63.

  10. Ramaekers JG, Moeller MR, van Ruitenbeek P, et al. Cognition and motor control as a function of Delta9-THC concentration in serum and oral fluid: limits of impairment. Drug Alcohol Depend. Nov 8 2006;85(2):114-22.

  11. Stinson FS, Ruan WJ, Pickering R, Grant BF. Cannabis use disorders in the USA: prevalence, correlates and co-morbidity. Psychol Med. Jul 20 2006;1-14.

  12. Strasser F, Luftner D, Possinger K, et al. Comparison of orally administered cannabis extract and delta-9-tetrahydrocannabinol in treating patients with cancer-related anorexia-cachexia syndrome: a multicenter, phase III, randomized, double-blind, placebo-controlled clinical trial from the Cann. J Clin Oncol. Jul 20 2006;24(21):3394-400.

  13. Zuardi AW, Crippa JA, Hallak JE, et al. Cannabidiol, a Cannabis sativa constituent, as an antipsychotic drug. Braz J Med Biol Res. Apr 2006;39(4):421-9.

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Further Reading

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Keywords

Cannabis sativa, C sativa, marijuana, tetrahydrocannabinol, THC, hashish, ganja, pot, weed, reefer, grass, joint, roach, dope, spliff, herb

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Contributor Information and Disclosures

Author

Lina Cassandra Vawter, MD, Resident, Department of Psychiatry, University of Massachusetts Memorial Medical Center
Lina Cassandra Vawter, MD is a member of the following medical societies: American Medical Association, American Psychiatric Association, and Massachusetts Medical Society
Disclosure: Nothing to disclose.

Coauthor(s)

Caroline Fisher, MD, PhD, Associate Director of Psychiatric Education & Training, Assistant Professor of Psychiatry, Consulting Staff in Pediatric Neurology, Department of Psychiatry, University of Massachusetts Medical School; Medical Director and Co-owner, Pediatric Behavioral Health, LLC
Caroline Fisher, MD, PhD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Child and Adolescent Psychiatry, and American Psychiatric Association
Disclosure: Nothing to disclose.

Medical Editor

Barry I Liskow, MD, Vice Chairman, Director Psychiatry Residency Program, Professor, Department of Psychiatry, University of Kansas Medical School
Barry I Liskow, MD is a member of the following medical societies: American Academy of Addiction Psychiatry
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

David Bienenfeld, MD, Vice-Chair, Program Director, Professor, Department of Psychiatry, Wright State University School of Medicine
David Bienenfeld, MD is a member of the following medical societies: American Medical Association, American Psychiatric Association, and Association for Academic Psychiatry
Disclosure: Nothing to disclose.

CME Editor

Harold H Harsch, MD, Program Director of Geropsychiatry, Department of Geriatrics/Gerontology, Associate Professor, Department of Psychiatry and Department of Medicine, Froedtert Hospital, Medical College of Wisconsin
Harold H Harsch, MD is a member of the following medical societies: American Psychiatric Association
Disclosure: lilly Honoraria Speaking and teaching; BMS Honoraria Speaking and teaching; Forest Labs Honoraria Speaking and teaching; AstraZeneca Honoraria Speaking and teaching; Pfizer Grant/research funds Other; Northstar Grant/research funds Other; Novartis  Other; Pfizer Honoraria Speaking and teaching

Chief Editor

Stephen Soreff, MD, President of Education Initiatives, Nottingham, NH; Faculty, Metropolitan College of Boston University, Boston, MA
Stephen Soreff, MD is a member of the following medical societies: American College of Mental Health Administration and American Psychosomatic Society
Disclosure: Nothing to disclose.

 
 
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