Reefer: Madness? Psychiatry and Cannabis Kenneth Boss, MD, FRCP - - PowerPoint PPT Presentation

Reefer: Madness? Psychiatry and Cannabis Kenneth Boss, MD, FRCP

DISCLOSURE

• Declare if you have a conflict of interest or not

OBJECTIVES

• 1. Identify implications of cannabis legalization on youth and

young adults;

• 2. Counsel patients on psychiatric implications of marijuana use;
• 3. Describe the process for patients obtaining medical marijuana

in the Nipissing District;

OUTLINE

• Benefit: Marijuana as a therapeutic agent
• Risk: Psychiatric comorbidity of cannabis use
• Summary of CPA Position Paper “Implications of

Cannabis Legalization on Youth and Young Adults”

• Outline processes to obtain medicinal marijuana in the

Nipissing District (time permitting)

• Proposed response to patients seeking medical

marijuana

MEDICAL MARIJUANA- EVIDENCE

• Chronic pain and spasticity (medium)
• inhaled more effective
• Nausea and vomiting during chemotherapy (low)
• Anorexia in HIV/AIDS (low)
• Sleep disorders (low)
• Tourette syndrome (low)

CANNABIS-PSYCHIATRIC COMORBIDITY

• Bidirectional comorbidity between mental illness and cannabis

use

• Association vs causation
• Secondary mental disorder
• Stress-diathesis; “two hit”
• Greater exposure related to later development of scz?
• Secondary cannabis use disorder
• “self-medication” hypothesis (not supported)
• Cumulative risk/common factors hypothesis

PSYCHIATRIC COMORBIDITY:PSYCHOSIS

• Psychosis
• Chronic cannabis use is associated with later development of

schizophrenia

• Cannabis users: 2-3x rate of schizophrenia
• Earlier age of onset of use, more intense use, and higher

THC content strengthen scz association

• Use in scz associated with relapse, rehospitalizations,

positive symptoms (not negative) and poorer functioning

PSYCHIATRIC COMORBIDITY: MOOD AND ANXIETY DISORDERS

• Heavy cannabis users have increased risk of developing

depression (OR 1.62)

• Cannabis use associated with increased risk of new-onset

manic symptoms (OR 2.97)

• Prospective studies show mixed results on development of

anxiety disorders in marijuana use

CANNABIS- NEUROPSYCHOLOGICAL IMPACT

• Acutely impairs:
• Attention
• Concentration
• episodic memory
• associative learning
• Evidence of long-term impairment mixed
• Some prospective studies indicate that greater intensity of use

associated with greater persistence of impairment

• Meta-analysis of studies showed no difference from controls after 1

month abstinence

CANNABIS USE IN ADOLESCENCE

• Lower educational attainment and greater use of other drugs
• No association with poor school performance or psychological

health

• Two recent longitudinal studies found no association with

academic performance or mental health problems when corrected for current alcohol and tobacco use

CRA POSITION PAPER

• Neurodevelopment continues into mid-20s
• Regular usage associated with cognitive deficits
• Abstinence “may improve some, but not all” of these deficits
• Early regular use increases risk of developing psychotic illness

“in those vulnerable”

• May be associated with progression to other illicit drug use

(esp. with high frequency, early use)

CPA POSITION- RECOMMENDATIONS

• Age of access to cannabis should not be prior to age 21, with

restrictions on quantity and THC potency for those between 21 and 25 years of age

• Support for public health education and resources targeting

youth and young adults

• Further biological and psychosocial research on impact of

cannabis and its legalization on mental health.

• Expand support for prevention, early identification and cannabis

cessation treatments (i.e., using change- based treatment models including harm reduction strategies)

• Advertising and marketing guidelines with clear markings of

THC and cannabidiol content/consistent public health warning messaging, including potential adverse consequences of the use of cannabis during pregnancy.

WHAT TO TELL PATIENTS?

• For most patients, there is inadequate evidence of benefit or

harm

• Up to age 25, ongoing neurodevelopment has led many to

proscribe its use

• Evidence of medical benefit is not strong, and does not exist for

any psychiatric illness

• Some vulnerable individuals may be prone to psychiatric

sequelae