The Therapeutic Cannabis User: 5 Key Issues

Psychiatric TimesVol 35, Issue 5
Volume 35
Issue 5

A drug once seen as a widespread danger to society is now experiencing renewed interest as a treatment for medical conditions, including a number of mental health conditions. This brief review explores 5 key issues clinicians can consider when encountering the therapeutic cannabis user.

William Casey/

William Casey/

DSM 5 criteria for cannabis use disorder severity

Table. DSM 5 criteria for cannabis use disorder severity

The first two decades of the 21st century have seen a shift in the public’s perception of therapeutic cannabis use. A drug once seen as a widespread danger to society is now experiencing renewed interest as a treatment for medical conditions, including a number of mental health conditions.1

Unlike other federally approved drugs, which are vetted through carefully monitored clinical trials assessing both safety and efficacy, the legalization of whole plant cannabis products (WPCP) for medical use across states has been mostly decided through popular referendum. Presently, the efficacy and safety of therapeutic cannabis use in all mental health conditions remains equivocal and few medical indications are supported by clinical trial data.

The new wave of cannabis legalization has been accompanied by an increase in the dissemination of industry-driven marijuana advocacy content across all media platforms.2 Consequently, recreational and therapeutic cannabis use is growing nationally without a strong foundation of clinical research to guide its use. Under these new conditions, psychiatrists are increasingly likely to encounter patients who report that they use cannabis to treat their mental health conditions, regardless of its legality in their state.

The current use of cannabis for mental health conditions departs from the traditional paradigm of prescribed medications for clinical practice in 2 specific areas. First, doctors cannot base their treatment plans on high quality clinical trials. Second, doctors cannot reliably restrict access to cannabis as it is easily accessed through either legal or illegal avenues. As a result, many practitioners can find encounters with patients identifying as therapeutic cannabis users to be awkward and anxiety producing.

This brief review explores 5 key issues clinicians can consider when encountering the therapeutic cannabis user.

Limitations in the evidence base

There are anecdotal reports of WPCP improving symptoms across a range of mental health conditions, such as PTSD, depression, anxiety, sleep disorders, opiate dependence, traumatic brain injury, and even schizophrenia.1 The classification of cannabis as a Schedule 1 drug has hindered research into its potential therapeutic applications. Conducting research into WPCP has required considerable resources and bureaucratic skill in negotiating with the National Institute on Drug Abuse and the Drug Enforcement Administration to execute these studies, and the results from these studies have been limited. (Moderate evidence was found that cannabinoids, primarily nabiximols, were an effective treatment in improving short-term sleep outcomes in individuals with sleep disturbance associated with obstructive sleep apnea syndrome, fibromyalgia, chronic pain, and multiple sclerosis. There were no data for sleep outcomes in individuals with mental health conditions.)

A recent comprehensive review by The National Academy of Sciences, Engineering, and Medicine reported that there was limited evidence to support the use of WPCP for the treatment of mental health conditions.1 This conclusion followed from the absence of high quality data on effectiveness rather than the presence of disconfirming evidence or clear safety considerations, although safety concerns are raised about cannabis hastening the onset of schizophrenia in vulnerable individuals.

Clinical trials conducted by pharmaceutical companies have been the driving force of drug research since the latter 20th century. However, without the possibility of proprietary control over the botanical product, pharma has focused primarily on studying isolated and synthetic cannabinoids, which can be patented.

These products differ significantly in their specific effects and from tetrahydrocannabinol (THC), because most synthetics are full agonists, while THC is a partial agonist. Partial agonists are generally safer because as the dose is increased, these drugs act as antagonists blocking many toxic properties including overdose from the substance, in this case THC. Furthermore, THC compounds do not mimic the effects of WPCP as the synergistic effect of cannabinoids and terpenoids can create distinct pharmacological effects.3

Some states, notably Colorado and California, have increased support and funding for cannabis research to overcome these hurdles.4,5 Subsequently, a number of ongoing studies are investigating the use of cannabis in treating PTSD. Unfortunately, it remains likely that high-quality trials investigating the therapeutic effect of cannabis in other mental health conditions will be slow as long as the current disincentives remain in place. Currently, the psychiatrist faced with managing the therapeutic cannabis user has little clinical trial data to inform decisions.

Educating patients about risks

Like many other psychotropic drugs, cannabis predictably causes dependence and has a clear withdrawal syndrome. Cannabis products also can rapidly induce relaxation and euphoria, which can drive patterns of escalating use. Deferring to DSM-5 for assessing substance use disorders provides clinicians a helpful scaffold to assess when therapeutic cannabis use may begin to shift into a cannabis use disorder (Table). If a patient meets 4 or more of these criteria, he or she has objectively met requirements for a moderate cannabis use disorder, which should be recognized and treated.

Making time to discuss these criteria with the therapeutic cannabis user early in the course of use serves a dual purpose. First, it empowers the user to self-monitor for signs of escalating use. Second, it allows clinicians and patients to preemptively agree upon the conditions whereby cannabis use will no longer be supported as a therapeutic intervention.

Encouraging the adherence to established best practices

Patients use cannabis for a variety of reasons. Those who do so because of easy availability can be educated about other treatment options that have a stronger evidence base. These treatments in states where their cannabis use is prohibited boast the added benefits of not involving the user in illegal activity.

Clinicians can ensure that other viable options have not been missed in patients who report using cannabis because other treatments have failed. For example, while some early evidence suggested cannabis as a PTSD treatment, evidence-based best practices such as antidepressants or psychotherapies need to be tried first.

Adverse effects of cannabis

As research investigating therapeutic cannabis use has been difficult to conduct, information about adverse effects has been derived from recreational cannabis use.6 Differences in comorbidity, motivations, and patterns of use complicate generalizing this data from recreational cannabis use to therapeutic cannabis use, but some informed observations follow.

1. Therapeutic cannabis use should be restricted to adults. Substantial evidence associates cannabis use with the development of schizophrenia or other psychoses: risk is highest among the most frequent users and those who begin use at a young age.1 Moreover, initiating cannabis use at an earlier age increases the risk of cannabis use disorder and overdose.

2. Cannabis use increases the risk of vehicular accidents.1

3. Cannabis use impairs learning, memory, and attention.1 Frequent users of cannabis may experience these deficits for a considerable part of daily life. Tolerance may attenuate these deficits, which appear to resolve following abstinence.5

4. Maternal cannabis use during pregnancy is associated with lower birth weight of infant.1

5. Smoking cannabis worsens respiratory symptoms and increases chronic bronchitis episodes.1

6. Providers must be vigilant in assessing for worsening mental health attributable to cannabis use. Recreational cannabis users have a small increased risk of depression, suicide, and social anxiety.1 Furthermore, cannabis use can increase symptoms of mania and hypomania in recreational cannabis users who have bipolar disorder.1

When a Patient Won’t be Parted from Cannabis

When a Patient Won’t be Parted from Cannabis

The legal consequences of cannabis use

In the US, the use and possession of cannabis is illegal under federal law for any purpose, even medical. At the state level, policies regarding medical and non-medical use of cannabis vary greatly. Physicians, if able, should counsel patients about the legal ramifications of using cannabis products within their own state.

In all states, driving under the influence of cannabis is illegal, even if it has been prescribed for a medical condition. Similar to the driving-under- the-influence laws involving alcohol, if an offender has multiple past charges or is at fault in a serious accident, he or she can be charged with a felony. Marijuana paraphernalia should also be removed from vehicles because in some states this can be used as proof of cannabis intoxication even there hasn’t been any cannabis use.

Cannabis concentrates such as waxes, tinctures, and oils are prosecuted differently among states. For instance, in Texas, marijuana concentrates are not considered marijuana by Texas courts and are instead grouped with more serious drugs such as ecstasy, MDMA or molly, PCP, and mescaline. While possession of less than 4 ounces of pure leaf marijuana is typically classified as a misdemeanor, possession of cannabis concentrates is classified as a felony. Patients should be informed that a felony charge can seriously affect housing and employment prospects.

Adapting your practice

The psychiatric cannabis user can be a challenging patient to manage, because it can seem unethical to collaborate in a treatment plan involving a drug without a strong evidence base. However, clinicians who maintain this conservative position of viewing all cannabis use as a disorder needing treatment run the risk of appearing anachronistic and alienating patients.

The growing number of patients who use therapeutic cannabis do not have the same scruples as physicians do about using a drug without a traditional evidence base. Deferring to the lowest tier of evidence, these patients are satisfied using cannabis from their own anecdotal experience. Given the ubiquity of access to cannabis, with or without a prescription through legal or illegal channels, clinicians who want to remain relevant in treating therapeutic cannabis users must engage in earnest discussions about cannabis.

The effective clinician will create a non-judgmental environment that engenders the trust required to disclose therapeutic cannabis use. Once the alliance has been established the clinician can objectively discuss the pros and cons with the therapeutic cannabis user and the condition he or she is seeking to treat. Following the discussion, whether or not the patient decides to use cannabis, the clinician should provide assurance that he or she is available to work with the patient.


Dr. Witt-Doerringis a PGY 3 Psychiatry Resident; and Dr. Kostenis Professor of Psychiatry, Neuroscience, Pharmacology, Immunology and Rheumatology, and Vice-Chair, Psychiatry for Research, Baylor College of Medicine.


1. National Academy of Sciences. The Health Effects of Cannabis and Cannabinoids. Accessed April 5, 2018.

2. Krauss M, Sowles S, Sehi A, et al. Marijuana advertising exposure among current marijuana users in the US. Drug Alcohol Depend. 2017;174:192-200.

3. Russo E. Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects. Br J Pharmacol. 2011;163:1344-1364.

4. Colorado | Department of Public Health and Environment. Accessed April 5, 2018.

5. Center for Medicinal Cannabis Research. Accessed April 5, 2018.

6. Walsh Z, Gonzalez R, Crosby K, et al. Medical cannabis and mental health: a guided systematic review. Clin Psychol Rev. 2017;51:15-29.

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