Complex needs
Definition
NICE Guideline NG216 - Social work with adults experiencing complex needs

Adults with complex needs are defined as people aged 18 or over who need a high level of support with many aspects of their daily life, and relying on a range of health and social care services. This may be because of illness, disability, broader life circumstances or a combination of these. Complex needs may be present from birth or develop over the course of a person's life, and may fluctuate.
Plain English definition
Think Local Act Personal (TLAP) Jargon Buster

You may have complex needs if you require a high level of support with many aspects of your daily life and rely on a range of health and social care services. This may be because of illness, disability or loss of sight or hearing - or a combination of these. Complex needs may be present from birth, or may develop following illness or injury or as people get older.