Cannabis use and Mental Health

Dr. Ruwan M Jayatunge

Cannabis sativa (Marijuana) has been used throughout the world medically, recreationally and spiritually for thousands of years (Maule, 2015). It is the most commonly used illicit drug in the world (Wittchen et al., 2009). Despite being illegal in many countries it is easily obtainable and even homegrown (Delisi te al., 2006). According to the Results from the 2011 National Survey on Drug Use and Health the rate of marijuana use has had a steady increase since 2007. Cannabis use continues to constitute social and public health problem.

The cannabis plant (Cannabis sativa) has a long history of use both as a medicinal agent and intoxicant (ElSohly & Slade, 2005). There are over 400 chemicals in marijuana. Active compounds of cannabis, called cannabidols, have 64 active isomers. Only one metabolite, tetrahydrocannabinol (THC) is reported to be an active metabolite responsive for its effects (Morrison et al., 2009). THC usually refers to the naturally existing isomer of delta-9-THC, but also may include delta-8-THC. The delta-9-tetrahydrocannabinol contains psychoactive properties. Marijuana produces a number of characteristic behaviors in humans and animals, including memory impairment, antinociception, and locomotor and psychoactive effects (Sim-Selley, 2003).

THC leads to increased activation in frontal and paralimbic regions and the cerebellum (Chang   & Chronicle, 2007). Cannabinoids act on a specific receptor that is widely distributed in the brain regions involved in cognition, memory reward, pain perception, and motor coordination (Adams & Martin, 1996). Cannabis produces euphoria and relaxation, perceptual alterations, time distortion, and the intensification of ordinary sensory experiences (Hall, Solowij & Lemon 1994).

Although most people who smoke cannabis will develop neither severe mental health problems nor dependence, regular use of cannabis may be associated with a range of health, emotional, behavioural, social, and legal problems, particularly in young, pregnant, and severely mentally ill people (Winstock, Ford & Witton, 2010). Cannabis users who also smoke tobacco are more dependent on cannabis, have more psychosocial problems and have poorer cessation outcomes than those who use cannabis but not tobacco (Peters, Budne &, Carroll  2012).

The epidemiological studies indicate that approximately 10% of lifetime cannabis users meet the criteria for cannabis abuse or dependence (Anthony et al., 1994; Cottler et al., 1995; Hall et al., 1999). The epidemiological literature shows that cannabis use increases the risk of accidents (Hall, 2015) and risk of motor vehicle crashes (Hall & Degenhardt, 2009). Cannabis is currently one of the leading substances reported in arrests (Dennis et al., 2002).

Tolerance and dependence to cannabinoids develops after chronic use, as demonstrated both clinically and in animal models (Sim-Selley, 2003). According to Levin and colleagues (2011) Cannabis dependence is a substantial public health problem. A large body of evidence now demonstrates that cannabis dependence both behavioral and physical, does occur in about 7-10% of regular users, and that early onset of use, and especially of weekly or daily use, is a strong predictor of future dependence (Kalant, 2004). 

Cannabis dependence or cannabis use disorder is defined in the fifth revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) as a condition requiring treatment (Gordon   Conley & Gordon, 2013).
Cannabis withdrawal is an important component of cannabis dependence (Lee et al., 2014). As many as 85% of users experience withdrawal (Budney et al., 2004; Winstock et al., 2010). Cannabis withdrawal is characterized by craving, irritability, nervousness, depressed mood, restlessness, sleep difficulty, and anger. With the recent publication of the DSM-5, a cannabis withdrawal syndrome is now officially recognized with defined criteria (APA).

Studies show significant negative effects of smoking marijuana on physical and mental health as well as social and occupational functioning (Gazdek, 2014). Smoking marijuana is known to have hemodynamic consequences (Mittleman et al., 2001). Cannabis also has immunosuppressant and endocrine effects although the clinical significance of these is still not clear (Ashton, 2001). Cannabis smoking shows a dose-response relation with pulmonary risk in the same way that tobacco smoking does.

Although problems of cannabis use can arise at any level of use, however low, cannabis use disorders and other problems are more likely to arise in long term, heavy daily users than in casual, infrequent users. (Winstock, et al., 2010).
Longitudinal association between cannabis use and mental health has been studied by the researchers. Cannabis use is a known risk factor for a range of mental health problems (van Gastel et al., 2014).

Cannabis use has been associated with several adverse life outcomes including unemployment, legal problems, dependence and early school leaving (Serafini et al., 2013). Furthermore Monshouwer and colleagues (2006) specify that cannabis use is associated with aggression and delinquency. In addition Fergusson and Boden (2008) point out that greater welfare dependence and lower relationship and life satisfaction associated with cannabis abuse.

Majority of studies have suggested a significant cognitive decline in cannabis abusers compared to non-abusers and healthy controls (Shrivastava et al., 2011; Solowij, 1988). According to Kalant (2004) Cannabis use has been linked to a number of both short- and long-term health consequences, including depression, paranoia, learning problems, memory and attention deficits. In addition Cannabis use also causes symptoms of depersonalization, fear of dying and irrational panic ideas (Khan & Akella 2009).

Also cannabis use significantly increase the risk for manic symptoms (Henquet, Krabbendam & Graaf, 2006) and mania (Leweke & Koethe, 2008). Evidence indicates that cannabis use is considerably associated with both attempted and completed suicides among healthy youths (Serafini et al., 2013; Price et al., 2009).
Cannabis intoxication can occur shortly after cannabis use. The intoxication by cannabis is associated with subjective symptoms of euphoria, perceptual distortion, continuous giggling, sedation, lethargy, impaired perception of time, difficulties in the performance of complex mental processes, impaired judgment and social withdrawal (Crippa et al. 2012).

Some clinicians have noticed panic attacks with cannabis intoxication. Cannabis intoxication symptoms are usually gone after a maximum of one week abstinence (Lishman, 1988).
Heavy cannabis use could lead to an ‘amotivational syndrome which has been described as personality deterioration with loss of energy and drive to work (Tennant & Groesbeck, 1972; Johns, 2001). Cannabis-induced amotivational syndrome negatively impacts on volition, self care and social performance.

Cannabis-induced psychotic disorder (CIPD) refers to psychotic symptoms that arise in the context of cannabis intoxication (Morales-Muñoz et al., 2014). Cannabis use is a risk factor for the development of incident psychotic symptoms (Arendt et al, 2005; Kuepper et al., 2011) and exacerbates psychosis (Hall et al., 2004).  Hall and team (2004) state that cannabis use can precipitate schizophrenia in vulnerable individuals. Deficits in prepulse inhibition (PPI) and cannabis abuse are consistently found in schizophrenia (Morales-Muñoz et al., 2015).

Cannabis use in adolescence leads to a two- to threefold increase in relative risk for schizophrenia or schizophreniform disorder in adulthood (Arseneault et al., 2004). The abuse of cannabis by patients with psychiatric disorders such as schizophrenia and mood and anxious disorders has a negative impact both in the acute and advanced stages of these conditions (Diehl, Cordeiro &, Laranjeira, 2010).
Exposure to marijuana during a critical period of neural development may interrupt maturational processes (Jacobus et al., 2009). Adolescents appear more adversely affected by heavy use than adults (Schweinsburg, Brown & Tapert , 2008).

Chronic cannabis use may alter brain structure and function in adult and adolescent population (Batalla et al., 2013). Sami and colleagues (2015) suspect cannabis use may be associated with   dopamine signaling alterations. Fontes and team (2011) point out that cannabis use has been associated with prefrontal cortex (PFC) dysfunction.
Arseneault and colleagues (2004) were of the view that cases of psychotic disorder could be prevented by discouraging cannabis use among vulnerable youths.

Consequently Moore and team (2007) emphasize that sufficient evidence to warn young people that using cannabis could increase their risk of developing a psychotic illness later in life.
According to El Marroun and team (2009) maternal cannabis use, even for a short period, may be associated with several adverse fetal growth trajectories. Cannabinoids have the ability to cross the placental barrier to the foetus and are detectable in the breast milk of mothers who use cannabis (Liebke, 2001).

Current evidence indicates that cannabis use both during pregnancy and lactation, may adversely affect neurodevelopment, especially during periods of critical brain growth both in the developing fetal brain and during adolescent maturation, with impacts on neuropsychiatric, behavioural and executive functioning. Jaques (et al., 2014). Prenatal marijuana exposure is associated with adverse perinatal effects (Astley & Little, 1990).
The use of cannabis for medical purposes is a controversial but an important topic of public and scientific interest (Ware, Adams &Guy, 2005).

According to Grotenhermen and Müller-Vahl  (2012) cannabinoids are useful for the treatment of various medical conditions. Medicinal marijuana has been prescribed in chronic pain management, antiepileptic treatment in partial epilepsy, symptomatic relief in multiple sclerosis and chronic neuropathic pain. However severe risks are associated with the non-medicinal use of cannabis. Hill (2015) emphasizes that physicians should educate patients about medical marijuana to ensure that it is used appropriately and that patients will benefit from its use.

Although cannabis has valid medical applications, it has addictive potential. Heavy cannabis use may contribute to the development of significant psychosocial and health-related problems (Budney,, Vandrey and  Stanger 2010 ). Cannabis use clearly has serious implications for young people who are particularly sensitive to its psychotogenic effects (Kolliakou et al., 2012). Early interventions are essential in treating cannabis related disorders.

The prevalence of marijuana abuse and dependence disorders has been increasing among adults and adolescents. They continue to smoke the drug despite social, psychological, and physical impairments, commonly citing consequences such as relationship and family problems, guilt associated with use of the drug, financial difficulties, low energy and self-esteem, dissatisfaction with productivity levels, sleep and memory problems, and low life satisfaction ( Gruber   et al , 2003 ; Budney et al, 2007).

Despite the fact that there are large numbers of people with cannabis dependence, relatively little attention has been paid to the treatment of this condition (Nordstrom & Levin, 2007) also the   preventative strategies are still limited (Deoganet al., 2015).
Pharmacological and psychological interventions are recommended for the cannabis use disorder. Allsop and team (2014) propose cannabis extract nabiximols (Sativex) as a medication for cannabis withdrawal.

Levin and colleagues (2011) suggest Dronabinol for the treatment of cannabis dependence. Haney et al (2013) recommend the FDA-approved synthetic analog of THC nabilonewhich has higher bioavailability and clearer dose-linearity than dronabinol.
Steinberg and team (2002) suggest psychosocial treatment for cannabis dependence.  Among the psychological interventions Cognitive and behavioral therapies and motivational enhancement therapies have proven to be effective in cannabis withdrawal and dependence (Benyamina et al., 2008).

Motivational enhancement therapy is designed to help resolve ambivalence about quitting and strengthen motivation to change (Elkashef et al., 2008). Cognitive behavioral therapy (CBT) has demonstrated efficacy as both a monotherapy and as part of combination treatment strategies (McHugh, Hearon & Otto, 2010).
CBT for marijuana dependence has typically been delivered in 45- to 60-minute individual or group counseling sessions. The overall focus is the teaching of coping skills relevant to quitting marijuana and coping with other related problems that might interfere with good outcome.

Such coping skills include functional analysis of marijuana use and cravings, development of self-management plans to avoid or cope with drug-use triggers, drug refusal skills, problem-solving skills, and lifestyle management (Elkashef et al., 2008). In addition Litt and team (2008) highlight the efficacy of contingency management treatments for marijuana dependence.
Treatment of cannabis use among people with psychotic or depressive disorders is imperative.

Available studies indicate that effectively treating the mental health disorder with standard pharmacotherapy may be associated with a reduction in cannabis use and that longer or more intensive psychological intervention rather than brief interventions may be required, particularly among heavier users of cannabis and those with more chronic mental disorders (Baker, Hides & Lubman 2010).
As safer alternative some propose cannabis substitution which is a method of harm reduction.  Harm reduction refers to policies and programmes that aim to reduce the harms associated with the use of drugs.

Cannabis substitution can be an effective harm reduction method for those who are unable or unwilling to stop using drugs completely (Lau et al., 2015). Based on principles of public health, harm reduction offers a pragmatic yet compassionate set of strategies designed to reduce the harmful consequences of addictive behavior for both drug consumers and the communities in which they live (Marlatt, 1996).
Cannabis abuse can have a profound effect on the health of individuals, their families, and their communities. Prevention and intervention programs for marijuana abuse are highly essential. Early intervention initiatives and psycho education strategies are important in preventive actions.