Anxiety is a common symptom of depressive illness as well as of other disorders. It can be shown by both psychological and bodily symptoms. The former include fearfulness, panic attacks, worrying and avoidance of situations which experience shows induce fear (these are phobias of irrational avoidance and fear of harmless situations). Physical effects of anxiety include breathing difficulties, palpitation, sweating, trembling and feelings of bodily tension.

It is not unusual for these symptoms to occur in depressed people and indeed at times to dominate the pattern of symptoms. However, careful enquiry often allows the typical features of depression, such as insomnia, which thereby allows the correct diagnosis to be made.