"Youth and Marijuana: Is it as Harmless as we Like to Think?"

Transcription

1 "Youth and Marijuana: Is it as Harmless as we Like to Think?" Rea Chair of Affective & Anxiety Disorders Department of Psychiatry Schulich School of Medicine & Dentist Founder and Executive Director of the First Episode Mood and Anxiety Program (FEMAP), LHSC

2 Take-home Messages 1) Youth are at greater risk for and from addiction to MJ than adults 2) Regular MJ use in youth increases the risk for several psychiatric disorders 3) How MJ affects motivation is one of the most destructive aspects of its use 4) There are also harmful social and physical health consequences from MJ use

3 Outline The MJ situation in Canada and Ontario Youth and the brain Chemical facts about MJ Ways that MJ is problematic Direct effects on behaviour and brain function Effects on thinking and decision making Distortion of reward-processing in the brain Effects on the body beyond the brain

4 Outline The MJ situation in Canada and Ontario Youth and the brain Chemical facts about MJ Ways that MJ is problematic Direct effects on behaviour and brain function Effects on thinking and decision making Distortion of reward-processing in the brain Effects on the body beyond the brain

5 Canada is the only industrialized nation with over 15% of its population endorsing MJ use 2007

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9 Outline The MJ situation in Canada and Ontario Youth and the brain Chemical facts about MJ Ways that MJ is problematic Direct effects on behaviour and brain function Effects on thinking and decision making Distortion of reward-processing in the brain Effects on the body beyond the brain

10 The Human Brain and Adolescence Why is my teen so moody and impulsive? How does this relate to drug use/abuse?

11 The ability to cope adaptively with emotional events by volitionally altering one s emotional reactions is important for psychological and physical health as well as social interaction.

12 How the Brain Dictates our Behavior Two routes to action 1) Bottom up (instinctive, automatic, often not conscious); involves drives, impulses and biological needs emotional emotional processes, in other words 2) Top down (conscious control choice); choice); involves planning, delaying gratification, deciding whether or not to act on drives, impulses, emotions, biological needs

13 Top Down: Prefrontal cortex regulates emotions Bottom up: Emotions arise from limbic system system

14 The dorsal lateral prefrontal cortex, important for controlling impulses, is among the latest brain regions to mature without reaching adult dimensions until the early 20s.

15 It is argued that adolescence is a period of heightened vulnerability to risk taking because of a disjunction between novelty and sensation seeking (both of which increase dramatically at puberty) and the development of self-regulatory competence (which does not fully mature until early adulthood).

16 This disjunction is biologically driven, normative, and unlikely to be remedied through educational interventions designed to change adolescents perception, appraisal, or understanding of risk. Interventions should begin from the premise that adolescents are inherently more likely than adults to take risks, and should focus on reducing the harm associated with risk-taking behavior.

17 Brain development Brain development affects drug use In addition, it turns out that Drug use affects brain development

18 Evidence indicates that exposure to phytocannabinoids during the prenatal period, in addition to the adolescent period, can alter the temporally ordered sequence of events that occur during neurotransmitter development, in addition to negatively impacting neural cell survival and maturation. Exposure to marijuana during pregnancy might impact negatively on brain structure in the first years of postnatal life. Furthermore, early-onset (before age 17) marijuana use might also have damaging effects on brain composition.

19 So Adolescents are more likely to be controlled by bottom-up drives than by top-down reasoning, compared with how they were when younger or how they will behave as adults. It is often harder for adolescents to think their way out of emotional states and drives, including boredom, drug craving or other discomfort. By using MJ regularly during adolescents, youth are likely to impair the normal development of their brains.

20 Outline The MJ situation in Canada and Ontario Youth and the brain Chemical facts about MJ Ways that MJ is problematic Direct effects on behaviour and brain function Effects on thinking and decision making Distortion of reward-processing in the brain Effects on the body beyond the brain

21 Why do youth use marijuana? Thrill seeking: Euphoria, sensory distortion, escape from boredom Peer Pressure

22 Why do youth use marijuana? Emotion regulation Relief from anxiety, depression or other uncomfortable states (boredom)

23 The delta-9-tetrahydrocannabinol tetrahydrocannabinol (THC) and cannabidiol (CBD) THC: more means more stoned 1) impairs reaction on movement and responseinhibition tasks 2) causes acute psychotic symptoms THC 3) destabilizes brain function CBD: more means more stable CBD 1) does not impair performance or induce CBDpsychosis THC 2) appears to reduce anxiety 3) stabilizes brain function MJ from the 1960 s

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26 The delta-9-tetrahydrocannabinol tetrahydrocannabinol (THC) cannabidiol (CBD) balance CBD THC THC CBD MJ today (wheelchair weed) MJ from the 1960 s

27 8.0 THC concentrations in 2010 are generally between 20 and 30%. 6.0 THC_mean Year Concentration of THC (in %) in marijuana confiscated by police in London, Ontario over 25 years

28 Outline The MJ situation in Canada and Ontario Youth and the brain Chemical facts about MJ Ways that MJ is problematic Direct effects on behaviour and brain function Effects on thinking and decision making Increases risk for psychiatric disorders Distortion of reward-processing in the brain Effects on the body beyond the brain

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30 MJ use impairs how your brain works, even after 28 days of abstinence

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32 Signs of marijuana use Concentration problems Impaired judgment Confusion

33 Marijuana use impairs thinking, even after 28 days of abstinence

34 The cannabis users, compared to both control groups, had deficits on verbal fluency, visual recognition, delayed visual recall, and short- and long-interval prospective memory. These findings suggest that cannabis use leads to impaired executive function.

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36 Signs of marijuana use Aggressive Behaviour Hallucinations Lack of Motivation

37 Regular marijuana use in adolescence increases the risk for schizophrenia The pooled odds ration was 2.1 and could not be explained by confounding [variables] or reverse causality. Evidence suggests that cannabis is a component cause in the development and prognosis of psychosis.

38 Methods: In a longitudinal study of a representative birth cohort followed to adulthood [for over 20 years], we tested why cannabis use is associated with the emergence of psychosis in a minority of users, but not in others. Results:.. Carriers of the COMT valine[158] allele were more likely to exhibit psychotic symptoms and to develop schizophreniform disorder if they used cannabis. Cannabis use had no such adverse influence on individuals with two copies of the methionine allele.

39 Marijuana use increases the risk for mania Use of cannabis at baseline increased the risk for manic symptoms during follow-up (adjusted OR 2.70), adjusted for age, sex, educational level, ethnicity, single marital status, neuroticism, use of other drugs, use of alcohol, depressive symptoms and manic symptoms at baseline. The association between cannabis use and mania was independent of the prevalence and the incidence of psychotic symptoms. There is no evidence for reverse causality, as manic symptoms at baseline did not predict the onset of cannabis use during follow-up (OR 0.35).

40 Signs of marijuana use Social Withdrawal Paranoia Anxiety and/or depression

41 Regular marijuana use in adolescence increases the risk for depression A number of studies found a modest association between early-onset, regular cannabis use and later depression, which persisted after controlling for potential confounding variables. There is little evidence of an increased risk of later cannabis use among people with depression and hence little support for the self-medication hypothesis.

42 After adjustment for strong confounders, any use of cannabis at baseline predicted a modest increase in the risk of a first major depression (OR 1.62) and a stronger increase in the risk of a first bipolar disorder (OR 4.98). The risk of any mood disorder was elevated for weekly and almost-daily users.

43 A range of psychopathological conditions, including depressive, bipolar and less consistently anxiety disorders as well as the degree of their comorbidity are significantly associated with cannabis use and progression to cannabis use disorder, even when controlling for externalizing disorders.

44 How MJ affects motivation Perhaps the most frequent problem I see in my clinical psychiatry practice with youth who use MJ regularly.

45 Normal (before addictive drugs) Reward- Processing meter Enjoying a fine meal Enjoying a beautiful sunset Listening to great music Athletic/physical achievement Good times with friends/family Succeeding at something you ve worked hard for Great sex in a great relationship 0 Fun/Enjoyment Meter

46 Reward-Processing meter after use of addictive drugs (e.g., marijuana) Smoking dope Great Succeeding sex at something Athletic/physical Listening Good Enjoying times toa with Enjoying great you ve relationship worked a hard 0 for achievement great friends/family fine music meal beautiful sunset Fun/Enjoyment Meter

47 Reward-Processing meter after use of addictive drugs over time Smoking dope Taking e Popping oxys Snorting crack Succeeding Listening Good Great times sex to at in something with a 0 you ve Enjoying great great Athletic/physical friends/family worked music relationship a a hard for beautiful fine achievement meal sunset Fun/Enjoyment Meter

48 Social ramifications of frequent MJ use Dropping out of school Difficulty holding a good job Impaired relationships with friends/family Gang involvement Selling of drugs Sex trade involvement Moving up the ladder of harder drug use

49 Other social/physical ramifications

50 Long-terms physical effects Decreased sex drive Impotence Infertility Breathing Problems

51 In this study, ammonia was found in mainstream marijuana smoke at levels up to 20-fold greater than that found in tobacco. Hydrogen cyanide, NO, NO[x], and some aromatic amines were found in marijuana smoke at concentrations 3-5 times those found in tobacco smoke. Mainstream marijuana smoke contained selected polycyclic aromatic hydrocarbons (PAHs) at concentrations lower than those found in mainstream tobacco smoke, while the reverse was the case for sidestream smoke, with PAHs present at higher concentrations in marijuana smoke.

52 Take-home Messages 1) Youth are at greater risk for and from addiction to MJ than adults 2) Regular MJ use in youth increases the risk for several psychiatric disorders 3) How MJ affects motivation is one of the most destructive aspects of its use 4) There are also harmful social and physical health consequences from MJ use

53 We are doing research on MJ use at FEMAP Call or if you would like to hear more and see if you can participate extension