Fear is an automatic neurophysiological state of alarm characterized by a fight or flight response to a cognitive appraisal of present or imminent danger (real or perceived). Anxiety is linked to fear and manifests as a future-oriented mood state that consists of a complex cognitive, affective, physiological, and behavioral response system associated with preparation for the anticipated events or circumstances perceived as threatening. Pathological anxiety is triggered when there is an overestimation of perceived threat or an erroneous danger appraisal of a situation which leads to excessive and inappropriate responses.
Anxiety is one of the most common psychiatric disorders but the true prevalence is not known as many people do not seek help or clinicians fail to make the diagnosis.
Anxiety disorders appear to be caused by an interaction of biopsychosocial factors. Genetic vulnerability interacts with situations that are stressful or traumatic to produce clinically significant syndromes.
Anxiety can be caused by the following conditions:
Anxiety is one of the most common psychiatric disorders in the general population. Specific phobia is the most common with a 12-month prevalence rate of 12.1%. Social anxiety disorder is the next most common, with a 12-month prevalence rate of 7.4%. The least common anxiety disorder is agoraphobia with a 12-month prevalence rate of 2.5%. Anxiety disorders occur more frequently in females than in males with an approximate 2:1 ratio.
The significant mediators of anxiety in the central nervous system are thought to be norepinephrine, serotonin, dopamine, and gamma-aminobutyric acid (GABA). The autonomic nervous system, especially the sympathetic nervous system, mediates most of the symptoms.
The amygdala plays an important role in tempering fear and anxiety. Patients with anxiety disorders have been found to show heightened amygdala response to anxiety cues. The amygdala and limbic system structures are connected to prefrontal cortex regions, and prefrontal-limbic activation abnormalities may be reversed with psychological or pharmacologic interventions.
Characteristic Symptoms Pathological Anxiety
Cognitive symptoms: fear of losing control; fear of physical injury or death; fear of "going crazy"; fear of negative evaluation by others; frightening thoughts, mental images, or memories; perception of unreality or detachment; poor concentration, confusion, distractible; narrowing of attention, hypervigilance for threat; poor memory; and difficulty speaking.
Physiological symptoms: increased heart rate, palpitations; shortness of breath, rapid breathing; chest pain or pressure; choking sensation; dizzy, light-headed; sweaty, hot flashes, chills; nausea, upset stomach, diarrhea; trembling, shaking; tingling or numbness in arms and legs; weakness, unsteadiness, faintness; tense muscles, rigidity; and dry mouth.
Behavioral symptoms: avoidance of threat cues or situations; escape, flight; pursuit of safety, reassurance; restlessness, agitation, pacing; hyperventilation; freezing, motionless; and difficulty speaking.
Affective symptoms: nervous, tense, wound up; frightened, fearful, terrified; edgy, jumpy, jittery; and impatient, frustrated.
Anxiety Disorders as defined in the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM–5; American Psychiatric Association, 2013):
When the history and examination do not suggest the symptoms as arising from any other medical disorder, the initial laboratory studies may be limited to the following: complete blood cell count (CBC) chemistry profile, thyroid function tests, urinalysis, and urine drug screen.
If the anxiety symptoms are atypical or there are some abnormalities noted in the physical examination more detailed evaluations may be indicated to identify or exclude underlying medical conditions. This would include the following: electroencephalography, brain computed tomography (CT) scan, electrocardiography, tests for infection, arterial blood gas analysis, chest radiography, and thyroid function tests.
Acute anxiety may require treatment with a benzodiazepine. Chronic anxiety treatment consists of psychotherapy, pharmacotherapy, or a combination of both.
Pharmacotherapy: selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), benzodiazepines, tricyclic antidepressants, mild tranquilizers, and beta-blockers treat anxiety disorders. 
Psychotherapy: One of the most effective forms of psychotherapy is cognitive-behavioral therapy. It is a structured, goal-oriented, and didactic form of therapy that focuses on helping individuals identify and modify characteristic maladaptive thinking patterns and beliefs that trigger and maintain symptoms. This form of therapy focuses on building behavioral skills so that patients can behave and react more adaptively to anxiety-producing situations. Exposure therapy is utilized to move individuals towards facing the anxiety-provoking situations and stimuli which they typically avoid. This exposure results in a reduction in anxiety symptoms as they learn that their anxiety is causing them to experience false alarms and they do not need to fear the situation or stimuli and can cope effectively with such a situation.
Anxiety disorders have very high morbidity including substance abuse, alcoholism and major depression. in addition, the constant anxiety also increases the risk of adverse cardiac events. In others, anxiety impairs the ability to develop social relationships and worsens the quality of life. Severe anxiety has also been linked to high rates of suicides.
Characteristic features noted in individuals with clinical anxiety:
Anxiety disorders are very common and can present in diverse ways. Because the condition is underdiagnosed and associated with high morbidity, it is best managed by an interprofessional team consisting of a mental health nurse, psychiatrist, psychotherapist, social worker, and a primary care provider. Family members need to be educated about the disorder and help monitor the symptoms and provide support. A mental health nurse should closely follow these patients as suicidal ideations are not rare. The pharmacist should educate the patient on different medications, their benefits, and potential adverse effects. Collaboration between the team members is vital to ensure that no patient is neglected and that all patients are receiving an acceptable standard of care.
The outlook for patients with anxiety is guarded. Data indicate that the high rates of mortality are associated with adverse cardiac events. In those with social phobia, the condition leads to significant functional impairment and a very poor quality of life. The risk of suicides is also high in this population. Patients with anxiety need lifelong follow up because, despite drug therapy, relapse rates are high. (Level V)
|||Hawken T,Turner-Cobb J,Barnett J, Coping and adjustment in caregivers: A systematic review. Health psychology open. 2018 Jul-Dec [PubMed PMID: 30450216]|
|||Domhardt M,Geßlein H,von Rezori RE,Baumeister H, Internet- and mobile-based interventions for anxiety disorders: A meta-analytic review of intervention components. Depression and anxiety. 2018 Nov 19 [PubMed PMID: 30450811]|
|||Lahousen T,Kapfhammer HP, [Anxiety disorders - clinical and neurobiological aspects]. Psychiatria Danubina. 2018 Dec [PubMed PMID: 30439809]|
|||Remes O,Wainwright N,Surtees P,Lafortune L,Khaw KT,Brayne C, Generalised anxiety disorder and hospital admissions: findings from a large, population cohort study. BMJ open. 2018 Oct 27 [PubMed PMID: 30368445]|
|||Durazzo M,Gargiulo G,Pellicano R, Noncardiac chest pain: a 2018 update. Minerva cardioangiologica. 2018 Apr 11 [PubMed PMID: 29642692]|
|||Jafferany M,Khalid Z,McDonald KA,Shelley AJ, Psychological Aspects of Factitious Disorder. The primary care companion for CNS disorders. 2018 Feb 22 [PubMed PMID: 29489075]|
|||Cosci F,Fava GA,Sonino N, Mood and anxiety disorders as early manifestations of medical illness: a systematic review. Psychotherapy and psychosomatics. 2015 [PubMed PMID: 25547421]|
|||Chapdelaine A,Carrier JD,Fournier L,Duhoux A,Roberge P, Treatment adequacy for social anxiety disorder in primary care patients. PloS one. 2018 [PubMed PMID: 30395608]|
|||Rickels K,Moeller HJ, Benzodiazepines in anxiety disorders: Reassessment of usefulness and safety. The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry. 2018 Sep 25 [PubMed PMID: 30252578]|
|||Kreuze LJ,Pijnenborg GHM,de Jonge YB,Nauta MH, Cognitive-behavior therapy for children and adolescents with anxiety disorders: A meta-analysis of secondary outcomes. Journal of anxiety disorders. 2018 Oct 30 [PubMed PMID: 30447493]|
|||Pereira AS,Willhelm AR,Koller SH,Almeida RMM, Risk and protective factors for suicide attempt in emerging adulthood. Ciencia [PubMed PMID: 30427447]|