Why tobacco and cannabis? High smoking rates amongst those with SUD (Guydish et al, 2016) Used together but clinically separated Unintended consequence of tobacco addiction Poorer cessation outcomes for co-users (Peters et al, 2012) Increasing concern about impact of cannabis use; potency increased (EMCDDA, 2018, Freeman et al 2018, 2019) Unique, complex relationship

1. Developing the
evidence base for
an intervention to
address tobacco
and cannabis use
HANNAH WALSH
PHD STUDENT,
MENTAL HEALTH
NURSE
INSTITUT CATALA
D’ONCOLOGIA,
BARCELONA
18TH MARCH 2019

2. Florence Nightingale Faculty of
Nursing, Midwifery and Palliative
Care
Supervisors:
Dr Maria Jose Duaso
Lecturer, Adult Nursing
Professor Ann McNeill
Professor of Tobacco
Addiction, National Addictions
Centre, Institute of Psychiatry,
Psychology and Neuroscience

3. Plan for today
1. Rationale for my PhD study – motivations, questions,
hypotheses
2. Background: tobacco and cannabis use in the UK and
Spain
3. Systematic review findings
4. Preliminary survey findings
5. Next steps

4. Why tobacco and
cannabis?
High smoking rates amongst those with SUD
(Guydish et al, 2016)
Used together but clinically separated
Unintended consequence of tobacco
addiction
Poorer cessation outcomes for co-users (Peters
et al, 2012)
Increasing concern about impact of cannabis
use; potency increased (EMCDDA, 2018, Freeman
et al 2018, 2019)
Unique, complex relationship

5. Cannabis, THC and CBD
Hash,
resin,
hashish
High
potency,
‘skunk’
THC and
CBD

6. Harms associated with cannabis use
Acute:
◦ Impaired attention, memory, psychomotor performance
◦ increased risk of road traffic accidents
◦ Increased risk of psychosis
Most likely chronic effects:
◦ dependence (1 in 10 users)
◦ subtle cognitive impairment
◦ pulmonary disease and respiratory symptoms
◦ malignancy of the oropharynx
Adolescent cannabis use:
◦ impaired personal and educational attainment
◦ higher rates of truancy, delinquency, criminality, higher rates of other substance
misuse, lower employment
◦ potential exacerbation of mental health conditions such as anxiety, depression and
psychotic disorders
Winstock et al, 2010

7. Cannabis use across Europe in young adults
EMCDDA data, 2018

9. UK treatment services
Tobacco cessation:
◦ Stop Smoking Services, funded by Public Health
England
◦ Behavioural treatment + NRT
◦ Specialist stop smoking services for those with
mental health problems, pregnant women
◦ Free NRT prescriptions for all on social security
benefits
Cannabis use disorder
◦ Substance use disorder treatment provided by
third sector
◦ Most services focus on other substance use, i.e.
heroin or alcohol dependence
◦ 2.3% of UK population report CUD; but only
14.6% of these ever accessed treatment (McManus
2014)

10. Tobacco and
cannabis:
a unique
relationship
psychological
physiological
(co)
dependence
How do these
factors influence
quitting either, or
both?

11. Doctoal thesis:
Aims
To describe profiles of co-smokers, co-
quitters and trying-to-quitters
To build up the evidence and
background theory to support an
intervention
To develop a logic model for an
intervention which addresses both
tobacco and cannabis

12. Who and what to target?
Tobacco treatment seekers?
Cannabis treatment seekers?
Treatment seekers or general population?
What age?
Where?

13. Medical Research Council complex
intervention development framework
Carry out a systematic review of interventions which address both
substances
To carry out a questionnaire survey to ascertain patterns of co-
smoking, motivation to quit, history of quit attempts, potential
sources of support for quitting
- To carry out qualitative interviews with co-smokers, to further
explore similar questions as above
-Develop a logic model for an intervention to address both tobacco
and cannabis
-COM-B used for development of survey questions and qualitative
interviews

14. Systematic review & meta-analysis
Aims: To identify studies reporting on interventions addressing tobacco
and/or cannabis use, and reporting on change in use of both substances post intervention
Methods: 5 databases were searched between 1990 and 2018, to identify intervention studies which
either;​
- Targeted both tobacco and cannabis use (including multi-substance interventions) OR​
- Targeted either tobacco or cannabis use, but which reported on use of both pre and
post intervention​
RCTs, feasibility and pilot studies were included.​
Data were also collected from some authors (n=13) on sample of co-users at baseline only. Raw
or analysed data were provided by authors.
Outcome measures: Tobacco and cannabis reduction and cessation rates for CO-USERS ONLY
were extracted

15. Results (preliminary, not peer reviewed)
20 studies were found; 12 RCTs, 8 pilot or feasibility studies, mostly US
◦ Cannabis focus = 7
◦ Dual focus = 6
◦ Multi-substance interventions = 6
◦ Tobacco focus =1
◦ Dual studies:
◦ Appear feasible
◦ Becker 2015: used a group format; included motivation intervention prior to treatment intervention,
dual abstinence = 7% at 6 months

16. Meta-analyses (preliminary, not peer reviewed)

17. SR and MA conclusions (preliminary, not peer
reviewed)
1. Interventions targeting either cannabis, tobacco or multi-substance
interventions have minimal or no effect on tobacco or cannabis cessation; little
difference seen between target of intervention. Some effect on cannabis
reduction noted. Further research is required to disentangle the potential
reasons why outcomes for co-users appear poor.
2. Dual interventions demonstrate feasibility; motivation may be an issue
3. Measurement outcomes require attention – variety across measurement of
cannabis, and differences between tobacco and cannabis measurement

18. Survey of co-use and “co-quitting”
•3 FE colleges distributed online survey by email; 150 responses so far
•Age range 16-30; most aged 16-19
•Invited to participate if current or recent tobacco AND cannabis user
•Detailed questions on tobacco, cannabis use; tobacco and cannabis quit motivation and quit
attempts;
◦ 41% daily tobacco users, 22% daily cannabis users
◦ 78% reported joints as most common ROA
◦ 8% quit both; 13% tried to quit both
◦ 21% tried to stop tobacco; 3% tried to stop cannabis
◦ 63% reported some motivation to quit tobacco; only 19% reported some motivation to quit
cannabis

19. Qualitative interviews
Who do you know
who has quit tobacco
or cannabis?
What would influence
you to quit smoking
tobacco or cannabis?
Michie et al, 2011

20. Logic model example:
capability, opportunity, motivation
What behaviour
am I trying to
change?
SR: Dual studies
focus on
motivation
Existing theory of
behaviour
change- COM-B
Survey: e.g.
motivation to quit
tobacco higher
Qualitative: e.g.
unaware sources
of support
e.g. Ensure access
to NRT

21. Thank you for listening
Hannah.walsh@kcl.ac.uk
@hannaheawalsh

22. References
European Monitoring Centre for Drugs and Drug Addiction (2018), European Drug Report 2018: Trends and Developments, Publications Office of the
European Union, Luxembourg.
Freeman, T. P., Groshkova, T., Cunningham, A., Sedefov, R., Griffiths, P., and Lynskey, M. T. ( 2019)Increasing potency and price of cannabis in Europe,
2006–16. Addiction, https://doi.org/10.1111/add.14525.
Freeman, T., Van der Pol, P., Kuijpers, W., Wisselink, J., Das, R., Rigter, S., . . . Lynskey, M. (2018). Changes in cannabis potency and first-time
admissions to drug treatment: A 16-year study in the Netherlands. Psychological Medicine, 48(14), 2346-2352. doi:10.1017/S0033291717003877
Guydish, J., Passalacqua, E., Pagano, A., Martínez, C., Le, T., Chun, J., Tajima, B., Docto, L., Garina, D., and Delucchi, K. ( 2016) An international
systematic review of smoking prevalence in addiction treatment. Addiction, 111: 220– 230. doi: 10.1111/add.13099.
McManus S, Bebbington P, Jenkins R, Brugha T. (eds.) (2016) Mental health and wellbeing in England: Adult Psychiatric Morbidity Survey 2014.
Leeds: NHS Digital.
Michie S, van Stralen MM, West R. The behaviour change wheel: a new method for characterising and designing behaviour change
interventions. Implement Sci. 2011;6:42. Published 2011 Apr 23. doi:10.1186/1748-5908-6-42
Peters, E. N., Budney, A. J. and Carroll, K. M. (2012), Clinical correlates of co‐occurring cannabis and tobacco use: a systematic review. Addiction,
107: 1404-1417. doi:10.1111/j.1360-0443.2012.03843.x
Winstock Adam R, Ford Chris, Witton John. Assessment and management of cannabis use disorders in primary care BMJ 2010; 340 :c1571