Unmet physical needs are widely regarded as the most common trigger for challenging behaviour in dementia. Pain is particularly significant because many people with dementia cannot reliably communicate that they are hurting. Infections such as urinary tract infections can cause sudden and dramatic changes in behaviour, including agitation and confusion. Hunger, thirst, discomfort, constipation, and fatigue are also frequent triggers. Environmental factors such as too much noise, unfamiliar surroundings, or a sudden change in routine can also provoke distress. Addressing the underlying need is nearly always more effective than attempting to manage the behaviour directly.