Anxiety is distinguished from fear, which is an appropriate cognitive and emotional response to a perceived threat. Anxiety is related to the specific behaviors of fight-or-flight responses, defensive behavior or escape. It occurs in situations only perceived as uncontrollable or unavoidable, but not realistically so. David Barlow defines anxiety as "a future-oriented mood state in which one is not ready or prepared to attempt to cope with upcoming negative events," and that it is a distinction between future and present dangers which divides anxiety and fear. Another description of anxiety is agony, dread, terror, or even apprehension. In positive psychology, anxiety is described as the mental state that results from a difficult challenge for which the subject has insufficient coping skills.
Until recently, panic disorder was not distinguished from agoraphobia (distressing anxiety resulting from being outside the home, travelling via public transit, being in open or claustrophobic environments, or being in crowds that generally leads to extreme avoidance due to fear of not being able to escape in those situations; APA, 2013). As it stands in the current Diagnostic and Statistical Manual of Mental Disorders - 5 agoraphobia is one of the most common disorders to co-occur with panic disorder. Current estimates contend that just under 2% of teens and adults have agoraphobia (Kessler et al., 2012). Often, people associate panic attacks or their panic disorder with certain places, people, or events and the fear of another attack occurring can lead to comorbid fears of the location or idea that there is no escape, which leads to extreme avoidance. Panic disorder can also occur simultaneously with other anxiety disorders, such as Generalized Anxiety Disorder (GAD) and/or Social Anxiety Disorder (SAD), for example.
Many medical conditions can cause anxiety. This includes conditions that affect the ability to breathe, like COPD and asthma, and the difficulty in breathing that often occurs near death. Conditions that cause abdominal pain or chest pain can cause anxiety and may in some cases be a somatization of anxiety; the same is true for some sexual dysfunctions. Conditions that affect the face or the skin can cause social anxiety especially among adolescents, and developmental disabilities often lead to social anxiety for children as well. Life-threatening conditions like cancer also cause anxiety.
Obsessive-compulsive and related disorders are characterized by obsessive, intrusive thoughts (e.g. constantly worrying about staying clean, or about one's body size) that trigger related, compulsive behaviors (e.g. repeated hand-washing, or excessive exercise). These behaviors are performed to alleviate the anxiety associated with the obsessive thoughts. These types of disorders can restrict participation in everyday life and/or generate significant distress, for instance, by making it difficult to leave the house without many repetitions of a compulsive behavior (e.g. checking that the doors are locked). Periodically experiencing worry or having a few "idiosyncratic" habits does not constitute an obsessive-compulsive or related disorder. Instead, these disorders are characterized by unusually high levels of worry and related compulsive behaviors, in comparison with a typical range of individuals.
Anxiety disorders reflect disorders that share a general feature of excessive fear (i.e. emotional response to perceived or real threat) and/or anxiety (i.e. anticipation of future threat) and demonstrate behavioral and functional disturbances as a result. Panic attacks are a feature that can occur in the context of many anxiety disorders and reflect a type of fear response.
People with panic disorder often worry about when the next attack will happen and actively try to prevent future attacks by avoiding places, situations, or behaviors they associate with panic attacks. Worry about panic attacks, and the effort spent trying to avoid attacks, cause significant problems in various areas of the person’s life, including the development of agoraphobia (see below).