Developments in the treatment of Cannabis related problems

Dr Jan Copeland

Prevalence of cannabis use in Australia - The 2001 Australian National Household Survey

36.9% males and 29.4& females had ever used cannabis
12.0% reported us in the past 12 months
26.6% ,ales and 22.6% females 14 -19 are recent cannabis users
Among that age group they are more likely to have smoked cannabis than tobacco

Statistics covering the use of cannabis in Australia and the UK were compared. Cannabis is by far the most widely used illegal drug in the UK

Cannabis use disorders in Australia

7.1% had used cannabis more than 5 times that year
2.2% met criteria for DSM IV cannabis use disorder (1.5% for dependence)
31.7% of current users met criteria for DSM IV cannabis use disorder (21% for dependence)
Those with cannabis dependence were three times more likely to have seen a professional for mental health problems than those without.

Cannabis treatment seeking

The rate of treatment seeking for cannabis problems has more than tripled since 1992 in Australia with 21% of treatment seekers reporting cannabis as the main drug of concern
The rate has doubled in the US to 14% of admissions in that period.
In the EU and Norway cannabis is the second most common illicit drug of concern with 12% of clients and 30% of new clients presenting with a primary cannabis problem.
ECA reported that 38% of those with a life time cannabis use disorder diagnosis reported active problems in the previous year with 57% reporting having used the drug in that period.

NB No mention of the legal and thus unregulated status of cannabis was made here and no assessment of the impact this has on the situation. No criticism of the legal regime was made in this presentation in fact.

Pharmacotherapies

Pharmacological interventions

NB using drugs to prevent cannabis use.

Antagonists

CB1 selective cannabinoid receptor antagonist SR141716 (Rimonabant): Blocks acute psychological and physiological effects of cannabis
Maybe useful with highly motivated clients but not yet trialled for this use

NB Rimonabant is an anti-obesity drug

Oral maintenance cannabis did not effect self-administration of cannabis in a laboratory study
Oral THC did decrease cannabis craving and withdrawal at a dose subjectively indistinguishable from a placebo

Other:
Buproprion (Zyban): exacerbates withdrawal but may reduce craving

NB Zyban is a treatment for nicotine addiction

Nefazodone: ameliorates anxiety and muscle pain during withdrawal

NB muscle pains are not a symptom of cannabis withdrawal, neither is anxiety. Nefazodone has been withdrawn in Canada due to liver damage.

Lithium Carbonate: Animal study demonstrated abolition of withdrawal syndrome

NB Lithium carbonate has serious side effects:
http://www.mentalhealth.com/drug/p30-l02.html
Precautions:
Lithium has a narrow therapeutic/toxic ratio - serum lithium concentrations must be measured regularly. Maintain patients on lithium therapy under careful clinical and laboratory control throughout treatment - periodic review and monitoring of kidney, cardiovascular and thyroid function is advisable. Gradual discontinuation of lithium is advised unless abrupt withdrawal is necessary because of toxicity. Safety/efficacy in children < 12 years of age not established. Women of childbearing potential, pregnancy, lactation: Assess expected benefits of therapy vs. possible hazards.

Cognitive behavioral interventions

US trials of group interventions

Group interventions
Stephensm Roffman and Simpson in 1993 looked a 212 randomly assigned to relapse prevention or social support discussion groups of 10 2-hour sessions with booster sessions at 3 and 6 months
Overall 36% of the sample were abstinent or improved (14.5% continuous) for the entire 12 months with no differences between groups

Stephens, Roffman et al in 1994 added a control group of 29 randomlt assigned to 14 group SS of RP over 18 weeks + 4 with partner versus 2 individual SS of MI 1 month apart versus delayed treatment (DTC)
Followed up at 4, 7, 13 and 16 months 1/12 - DTC lower abstinence than 2 intervention groups (9% vs 37%)
At 16/12 there were no sig diffs between the two Tx groups in number of days using. Cannabis related problems or dependence symptoms.

Barber and colleagues (2001)
A multi site study (n=450) of the effectiveness of brief treatment for cannabis dependence found 9 CBT sessions + case management more effective than 2 CBT sessions and both more effective than delayed treatment control in reducing cannabis use and associated problems 4 months post assessment with maintenance of change at 15 months.

Australian trial of CBT

A randomized controlled trial to either 6 sessions (n=78), 1 session (n=82) or delayed treatment control (n-69)
Exclusion criteria: <18 years, illiterate, >weekly use of other drugs except alcohol and nicotine, score >on AUDIT, received other cannabis treatment in the previous 12 weeks, in treatment for other substance use disorder, or significant acute axis 1 disorder

Motivational interview
Coping with urges and handling triggers
Management of withdrawal symptoms
Cognitive restructuring
Challenging positive expectancies
Coping skills training
Relapse prevention. Lifestyle modification

69% male
Mean age 32.3 (range 18 - 59 years)
64% full time employed
58% completed 6 years of high school
64% in a relationship and only 11% lived alone

Median age of first use = 15 years (range 7 - 45 years)
Median age regular use = 18 years (range 11 - 47 years)
Mean of 14.8 years of regular use (range 1 - 34 years)

34% has seen a GP in the previous 2 weeks
19% had been hospitalized in the last year
92% had previously attempted to moderate their cannabis use and 29% had sough help to do so
Only 3.5% had asked a GP for assistance in quitting but 54% had discussed their cannabis use with a GP

6 sessions group: Mean number of sessions attended = 4.2 with 9% attending no sessions and 50% attending all sessions
1 session group: 88% attended
Follow up was 74.2%

Continuous abstinence rates:
6SS = 15.1%
1SS + 4.9%
DTC = 0.0%

Adolescent populations

RDT of single session MI Vs no intervention in a college environment lead to significant reduction in cannabis use

US youth cannabis treatment experiment
5 promising interventions including motivational enhancement, skills based family support networks. Community reinforcement and multidimensional family therapy from 5 sessions to 30+
Adolescents 12 - 19 years, current DSM-IV CUD n= 600, 17% female
All interventions had an impact at 2, 6, 12 and 15 months outcome, but 5 sessions including motivational enhancement were more effective for low severity participants

Intensive multidimensional family therapy (Liddle et al 2001)
A randomized but not controlled study of adolescent cannabis users clinically referred reported superior outcomes at 12 months for this intervention compared with group therapy and mutli family education.

US teen marijuana check-up
Australian adolescent checkup

An intervention for non-treatment seeking adolescents
Based on the brief drinker checkup
Promising results for the reduction of cannabis use and related harms
RCT's in US and Australia following feasibility study

Psychiatric populations

Comorbid schizophrenia and cannabis use disorder
Pharmocotherepy: a small study found that clozopine led to higher rates of abstinence from cannabis than resperidone

No published RCT's but some evidence that brief MI or 4 session CBT are ineffective

Clinicians recommendations include integrated shared care or specialist services. Assertive outreach, motivational interventions, social support and a comprehensive and long term perspective

Conclusions:

Growing demand for cannabis intervention
CBT of between 1 and 9 sessions is promising for treatment seeking adults and adolescents, with intensive multidimensional family therapy for more complex problems
Check up and other motivational approaches showing promise for non-treatment seekers
Further development required for pharmacotherapies in general, and particularly for those with CO-morbid psychiatric disorders, in addition to development of psychological interventions for this group.
Need for development of earlier and more accessible interventions for cannabis related problems eg in web based, primary health care or educational settings.