Separation anxiety disorder
This involves someone feeling excessively and persistently fearful about being away from a person to whom they are strongly attached – in children the focus is usually a caregiver whereas in adults it is more likely to be a child or romantic partner – to the point that it causes a deterioration in functioning. Examples include refusing to go out or sleep away from home because of worries about losing the person they are closest to, or experiencing nightmares about separation.

Selective mutism
Characterised by consistent selectivity in speaking, e.g. the individual (usually a child) is competent in language at home but doesn’t speak at school, which is not due to a different language being used in the two locations. The issue lasts for at least one month, is not limited to the first month of school, and is sufficiently severe so as to interfere with social communication or educational progress.

Hypochondriasis
Features a persistent preoccupation with the possibility of having one or more serious illnesses, which may manifest with repetitive health-related behaviours such as constantly researching symptoms or seeking reassurance from medical professionals, or denial such as missing appointments.

Other conditions
Other problems can overlap with anxiety including obsessive-compulsive disorder and post-traumatic stress disorder.