Much is known about the negative health effects of substance misuse for the individual. This paper set out to explore the morbidity and health costs for family members of those with a substance problem compared with relatives of people with asthma and diabetes. 'Disability and chronic illness of any kind affects the whole family. Having a family member with an alcohol or drug problem may have a negative effect on family functioning and dynamics and is associated with an increased risk of being diagnosed with a substance use disorder, depression, and trauma. GPs should bear this in mind when managing the families of those with problem substance abuse.'