Harmful use of alcohol kills more than 3 million people each year. 35 million people are estimated to be suffering from drug use disorders. Tobacco contributes to the death of more than 8 million people a year around the world.

It is important that people who have substance use problems receive interventions that are of high quality, ethical and have strong evidence-base.

Motivational interviewing (MI) can be used as a psychological treatment that aims to help people cut down or stop using substances.

Typically, a counsellor who is trained in MI works with a client to support them making...