Anxiety Disorders

Reviewed July 14, 2004

Teresa
Hermida, MD

Departments of
Psychiatry and
Psychology

As outlined in the Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV), anxiety disorders include not only generalized anxiety disorder (GAD), social anxiety disorder (SAD, also known as social phobia), specific phobia and panic disorder (PD), with and without agoraphobia, but also obsessive-compulsive disorder (OCD) and post-traumatic stress disorder (PTSD). These diagnoses describe constellations of anxiety symptoms commonly found in the general population. In the United States, these disorders afflict approximately 15.7 million people per year, with an additional 11.7 million people who suffer from anxiety along with another psychiatric disorder.¹ The economic burden of anxiety disorders in the United States in 1998 was estimated to be $63.1 billion. People suffering from anxiety disorders are often major utilizers of the nonpsychiatric medical system.¹ This makes the ability to recognize, diagnose and appropriately treat and triage those who have anxiety disorders an important part of primary medical practice.

PREVALENCE

Phobia is the most commonly seen anxiety disorder, with up to 49.5% of people reporting an unreasonably strong fear and 22.7% of those people meeting criteria for simple phobia.² Social anxiety disorder is the next most common disorder of anxiety, with 13.3% of people reporting symptoms which meet the DSM criteria.³ PTSD, which is often unrecognized, afflicts approximately 7.8% of the overall population⁴ and 12% of women, in whom it is significantly more common.⁵ Surprisingly, disorders that are more commonly recognized, such as GAD and PD, have lower lifetime prevalence rates of 4.1-6.6%^6,7 and 1.5% respectively. Of the panic sufferers, up to 40% also meet criteria for agoraphobia.⁸ Another often under-diagnosed disorder, OCD, is found in 2.5% of the population.⁹

PATHOPHYSIOLOGY

While definitive pathophysiological mechanisms have not yet been determined, anxiety symptoms and the resulting disorders are thought to be due to disrupted modulation within the central nervous system. Physical and emotional manifestations of this dysregulation are the result of heightened sympathetic arousal of varying degrees.¹⁰ Several neurotransmitter systems have been implicated to have a role in one or several of the modulatory steps involved. The most commonly considered are the serotonergic and noradrenergic neurotransmitter systems. In very general terms, it is thought that an underactivation of the serotonergic system and an overactivation of the noradrenergic system are involved. These systems regulate and are regulated by other pathways and neuronal circuits in various regions of the brain, resulting in dysregulation of physiological arousal and the emotional experience of this arousal.¹¹ Disruption of the gamma-butyric acid (GABA) system has also been implicated because of the response of many of the anxiety spectrum disorders to treatment with benzodiazepines.¹² More recently there has been some interest in the role of corticosteroid regulation and its relationship to symptoms of fear and anxiety.¹³ Corticosteroids may increase or decrease the activity of certain neural pathways, affecting not only behavior under stress, but also the brain's processing of fear-inducing stimuli.

Many studies indicate that a genetic predisposition to developing an anxiety disorder is likely.¹⁰ However, environmental stressors clearly play a role, in varying degrees. All of the disorders are affected in some way by external cues and how they are processed and reacted to.

SIGNS AND SYMPTOMS

A subjective experience of distress with accompanying disturbances of sleep, concentration, social and/or occupational functioning are common symptoms in many of the anxiety disorders. Despite their similarities, these disorders often differ in presentation, course and treatment.

Patients often present with complaints of poor physical health as their primary concern.⁸ This may temporarily distract from the underlying anxiety symptoms. This is particularly common in panic disorder, which is characterized by a short period of intense fear and a sense of impending doom, with accompanying physical symptoms, such as chest pain, dizziness and shortness of breath. Very often, these patients will first present to an emergency department.⁸ When complicated by agoraphobia, the individual fears having a panic attack in a place that prevents escape. This results in the patient avoiding such situations, with subsequent disturbances in functioning.¹⁴

GAD rarely occurs without a co-morbid psychiatric disorder,⁶ with the patient experiencing consistent worry over multiple areas of his or her life for at least 6 months.

SAD describes fear and anxiety in social situations leading to avoidance of social interaction. Specific phobia is characterized by similar symptoms and behavior, but is triggered by a specific object or situation, such as a fear of certain animals or heights.

PTSD and acute stress disorder occur after a patient experiences a traumatic event with subsequent physiological arousal in the face of stimuli that trigger memories of the event; avoidance of such stimuli; and a sense of re-experiencing the event. The latter occurs in the short term, while the former describe a more chronic version of the disorder.

Finally, OCD is characterized by repeated behaviors (compulsions), which serve to reduce anxiety connected to unwanted, intrusive thoughts (obsessions). Commonly seen behaviors are cleaning or washing in response to concerns about contamination, or repeatedly checking to see if a stove is turned off in response to concerns over a fire starting. Some people repeatedly check work or seek excessive reassurance due to obsessive self-doubt.

DIAGNOSIS

In order for a patient with symptoms of anxiety to be diagnosed with one of the disorders, DSM-IV criteria should be met (Table 1). Diagnosis is often complicated by frequent co-morbidity with other psychiatric disorders. Up to 60% of sufferers of GAD have a co-morbid condition, with PD and major depressive disorder being the most common.⁶ PD is often co-morbid with alcohol abuse, with an increased risk for suicidality.⁸ Agoraphobia is commonly connected to panic disorder with co-morbidity rates approaching 40%.¹⁵ Many of these disorders have overlapping signs and symptoms, requiring the clinician to explore several lines of questioning to clarify the primary diagnosis.

Table 1:

DSM IV Criteria for the Anxiety Disorders*

Click on a disorder for more information

*Excluding anxiety disorder due to a medical condition, substance-induced anxiety disorder, and anxiety disorder not otherwise specified.

In order to make a diagnosis of PD in a patient who is having panic attacks, there are several criteria that must be met (Table 1). Agoraphobia is not required to make the diagnosis of PD.

Important in the diagnosis of PTSD is identifying a history of trauma and being sure to ask questions related to avoidance, re-experiencing and physiological arousal in the face of triggering stimuli. The most common trauma associated with the disorder is rape.⁴ The symptoms of PTSD may be misconstrued for depression, other anxiety disorders and/or dysfunctional personality traits. Patients may not be able to identify a connection between the symptoms and the trauma history, requiring that the clinician be sensitive to the possibility that a trauma history exists. If the patient presents with complaints within 4 weeks of the trauma (with resolution within 4 weeks of symptom onset) then acute stress disorder should be the diagnosis.¹⁴

Patients with OCD are often secretive regarding their symptoms. These are secondary to feelings of shame and a sense of isolation. Many are not aware that others suffer from the same constellation of thoughts and behavior. Questions should explore whether certain routines are related to specific fears, thoughts and /or images.¹⁶ OCD is often co-morbid with major depressive disorder (in 2/3 of patients over lifetime) and panic attacks, with rates up to 60%.¹⁶ One must also distinguish between OCD and obsessive-compulsive personality disorder (OCPD). Although up to 25 % of patients suffering from OCD also suffer from OCPD, the two can present very differently. Interestingly, if the source of compulsive behavior is kept secret, a patient with OCD can sometimes appear to be suffering from psychosis. The treatment strategy for psychosis differs markedly, making it very important to distinguish between the two when presented with bizarre behavior. Questions should differentiate between "voices" and intrusive thoughts. The patient suffering from OCD knows his or her thoughts and actions are irrational.

The symptoms of SAD can also be confused with psychosis. One must distinguish between paranoia and the fear of being evaluated. Those suffering from SAD desire social interaction, but avoid it in order to reduce anxiety.¹⁴ When diagnosing specific phobia, the clinician should remember that the majority of patients who meet the criteria have more than one fear-inducing object or situation.²

Central to the diagnosis of any of the anxiety disorders is a good history, often requiring collateral from friends and family. One must also rule out any medical disorders, which may be causing the distress (eg, hyperthyroidism, pheochromocytoma), as well as substance abuse or dependence. It is important to note, however, that anxiety disorders are common and finding an underlying medical cause is unusual. Finally, the symptoms must result in a deficit in social and/or occupational functioning.

THERAPY

An important part of any intervention with a patient with an anxiety disorder is education. The practice guidelines for PD recommend education of the family as well.¹⁷ Many people are confused by the symptoms and behavior and are reassured to know they are not alone and that there are effective interventions.¹⁷ The patient should receive appropriate medical work-up, such as a physical exam, and studies (eg, EKG, TSH) when indicated. After ruling out a medical condition, developing a working alliance with the patient will provide a basis for ongoing management, and prevent further inappropriate utilization of the medical system.¹⁷

A combination of psychotherapy and medication management is recommended in all of the anxiety disorders.^6,9,17,18 Cognitive behavioral therapy (CBT) has the strongest support of all the psychotherapies, but requires commitment to treatment on the part of the patient.^10,17 Its efficacy is also contingent on the ability of the therapist and the length of therapy, with a 78% response rate in PD patients who have committed to 12-15 weeks of therapy.¹⁷ While therapy has the advantage of no physical side effects, some studies have found that CBT alone is inferior to medication alone,¹⁸ while others have shown that CBT alone has similar efficacy when compared to medication.¹⁹

The selective serotonin reuptake inhibitors (SSRIs) have been shown to be the best-tolerated medications, with response rates significantly higher than placebo for PD,¹⁷ OCD,⁹ PTSD,^5,20 SAD²¹ and GAD.²² This class of medication includes fluoxetine (Prozac), fluvoxamine (Luvox), citalopram (Celexa), paroxetine (Paxil) and sertraline (Zoloft). Some improvement should be noted within 3-4 weeks, with appropriate increase of the dose if no improvement is seen. In OCD, symptoms may take 8-12 weeks of treatment to respond. These patients often require doses at the higher end of the dosage range, so one should not be hesitant to make increases. It is also rare to achieve absolute resolution of symptoms in OCD, with partial reduction being the norm.⁹ In all of the anxiety disorders, SSRIs should be started at low doses and gradually titrated up to therapeutic levels, to avoid an initial exacerbation of anxiety.

Benzodiazepines, which have been used commonly in the past to treat anxiety disorders, continue to be useful in the short-term management of symptoms until acceptable reduction of symptoms is achieved with an SSRI and/or CBT.^6,17 The tolerability and lack of addiction potential make the SSRIs more desirable for long-term management, but the delay in response makes short-term symptom relief with a benzodiazepine desirable to those with the greatest impairment. Because of the risk for rebound anxiety on short half-life benzodiazepines, such as alprazolam (Xanax),⁶ many psychiatrists prefer the longer-acting benzodiazepines, such as clonazepam (Klonopin).

If a lack of response to the combination of CBT and medication occurs, a re-evaluation of symptoms may reveal a co-morbid disorder missed on the first exam. Many clinicians will try switching between SSRIs before considering the next step in treatment. Finally, a referral to a psychiatrist for further evaluation and management may be necessary if none of these strategies work. Treatment-refractory anxiety can be extremely frustrating for both patient and clinician. This can lead to increased dependence on benzodiazepines, and an escalation of doses required for the same effect.

When approaching the start of therapy, the clinician should provide reassurance that effective treatment is available, but that patience may be necessary until the right combination of modalities is found.

OUTCOMES

While all of the anxiety disorders display a significant amount of chronicity, the majority of people will have an improved outcome with appropriate treatment. Response rates improve when co-morbidity is low.^6,8,23 Patients with an earlier onset of symptoms (childhood/adolescence) can generally expect a more chronic course and may by more difficult to treat.^6,9,23 In some of the disorders (PTSD, PD), patients may have spontaneous remission, or be able to function despite the symptoms. However, time to resolution of symptoms is shortened and overall functioning can improve with treatment.^4,17

Pharmacotherapy often aids in relapse prevention, with improved rates when effective treatment is continued for 12 months.^17,24 When considering the termination of pharmacologic treatment, the risk for relapse in all of the disorders should be discussed with the patient. When discontinuing the SSRIs, a slow taper is recommended, with close monitoring for rebound symptoms (headache, GI upset, restlessness).¹⁷ If relapse occurs, reinstituting treatment is indicated, with many patients opting for indefinite treatment in order to maintain remission of symptoms.

Lifelong management with pharmacotherapy and/or psychotherapy is not unusual for many patients. For many, a maximal reduction of symptoms, rather than a full remission, is an acceptable outcome.⁹

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REFERENCES

Markowitz JS, Weissman MM, Ouellette R, Lish JD, Klerman GL. Quality of life in panic disorder. Arch Gen Psychiatry. 1989;46:984-92.

Eddy MF, Walbroehl GS. Recognition and treatment of obsessive compulsive disorder. Am Family Physician. 1998;57:1623-8,1632-4.

Kaplan HI, Sadock BJ. (1995) Comprehensive Textbook of Psychiatry/VI. 6th ed. Williams &Wilkins, Baltimore, Maryland. pp. 1244-48.

Ressler KJ, Nemeroff CB. Role of serotonergic and noradrenergic systems in the pathophysiology of depression and anxiety disorders. Depress Anxiety. 2000;12(Suppl 1):2-19.

Davidson JR. Pharmacotherapy of social anxiety disorder. J Clin Psychiatry. 1998;59(Suppl 17):47-53.

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Definition

Prevalence

Pathophysiology

Signs and
Symptoms

Diagnosis

Therapy

Outcomes

References