It is important to recognise that difficult behaviours serve a function for the person displaying them. It may be that a behaviour is present because the individual is experiencing fear, frustration, distress, sadness, or even excitement. They may be in pain, overwhelmed by environmental factors such as loud noise, or feel unable to communicate effectively.

PBS is a particularly important consideration for supporting people with severe cognitive impairments who as a consequence, have reduced awareness of their difficulties and an inability to self-manage their problems.