Loneliness is a common human emotion that is difficult to define, but generally speaking, refers to a feeling of disconnectedness and isolation as a consequence of having limited or no social interactions. It’s not the same as being alone, as many people enjoy solitude, and is associated more with a person’s deteriorating physical and mental health as a consequence of social isolation. Loneliness in old age is personal to every individual, so it can sometimes be easier to think about loneliness in terms of its symptoms than its causes.