Enhanced primary care management of common mental and substance use disorders is a key healthcare target. Though primary care may be well placed to achieve this target, a greater understanding of the prevalence and profile of common mental and substance use disorders in primary care settings is needed. We searched the MEDLINE database (2002–2012) to provide an update on biomedical literature describing the prevalence of common mental and substance use disorders in European general practice. Following “PRISMA” guidelines, 17 studies were kept for qualitative synthesis. Prevalence, profile, screening instruments, associated co-morbidities, and gender distribution were tabulated. Depending on the screening method, the prevalence of common mental and substance use disorders ranged from 10.4% (Luxemburg) to 53.6% (Spain). Mood disorders were the most common. High co-morbidity with anxiety and somatisation hindered early identification and management. The continuing burden of common mental and substance use disorders, coupled with poor identification described in the updated EU biomedical literature, suggests that the unmet need for health care – identified by the World Health Organization a decade ago – remains unmet. Understanding the prevalence of common mental and substance use disorders, associated morbidity, and the extent to which general practice represents an important catchment mechanism can enhance their management at this level. General practitioners should be trained in accurate screening. Short screening instruments for general practitioners should be unified and promoted.