Dual diagnosis is the term used to describe patients with both severe mental illness and problematic drug and/or alcohol use. The term originated from the USA in the 1980s and has been adopted in the UK more recently. It can also be described as co-occurring disorders and has been broadened to include any addictive behaviour.1 The nature of the relationship between the two conditions is well established and may be genetically linked.2
This is a companion discussion topic for the original article at https://patient.info/doctor/mental-health/dual-diagnosis-drug-abuse-with-other-psychiatric-conditions