Ms Hannah Walsh

I am a mental health nurse, and a PhD candidate at the Florence Nightingale Faculty of Nursing, Midwifery and Palliative Care at King’s College London. I have over ten years nursing experience in inpatient, community and Deaf mental health services, in leadership and in practice development. I was awarded an NIHR studentship to complete an MClinRes, and a Nightingale scholarship to undertake a PhD. My PhD is a mixed methods study which aims to develop the evidence base for an intervention to address tobacco and cannabis co-use amongst young adults, supervised by Dr Maria Duaso and Prof Ann McNeill at KCL. I am interested in health inequalities, mental health and substance misuse.

Measuring co-use of tobacco and cannabis: methodological findings from a systematic review and meta-analysis of treatment interventions

PhD Student

I am a mental health nurse by background, and have recently completed a Masters in Clinical Research. I am now undertaking a PhD at Kings College London, Florence Nightingale Faculty of Nursing and Midwifery.

Introduction and aims:

Co-use of tobacco and cannabis (co-administered or concurrent) is a complex form of polysubstance use. However, measurement of cannabis use and hence also co-use within the literature is less consistent than tobacco use.  Based on findings from a recent systematic review exploring treatment interventions for tobacco and cannabis (Walsh et al., in preparation), this methodological review aims to identify and evaluate methods used for tobacco, cannabis and co-use measurement.


The systematic review and meta-analysis (Walsh et al, in preparation) included studies targeting or reporting on changes in both tobacco and cannabis use post treatment intervention. This methodological review extracted methods described to measure tobacco, cannabis and co-use within included studies.


18 studies were included in the systematic review, all of which reported on use of tobacco and cannabis within treatment interventions. Most (n=13) used cigarettes per day to measure tobacco use, but cannabis outcomes varied considerably between and within amount and frequency of use.

No validated co-use scales were used, and co-use was not specifically measured in any study.


Whilst standardised measurement of tobacco use and cessation exist, they are not consistently used. Standardised measurement of cannabis is warranted.

A tool to measure co-use of tobacco and cannabis is required, in order to establish consumption patterns and to inform intervention design, and to avoid tobacco use in joints being overlooked.

Walsh, H; Duaso, M; McNeill A (in preparation) A systematic review and meta-analysis of interventions which address or measure co-use of tobacco and cannabis.


Dr Maria Duaso, Florence Nightingale Faculty of Nursing, Midwifery and Palliative Care, King’s College London Professor Ann McNeill, National Addictions Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London

Conflicts of interest:

No conflict of interest