Panic Disorder



Panic Disorder








Panic disorder (PD) is a debilitating disease. The estimated lifetime prevalence is 1.5% to 3.5% with an eightfold increased risk in first-degree relatives. The disorder has a bimodal peak in adolescence and mid 30s and may predispose to the development of other mental disorders (e.g., other anxiety disorders, mood disorders). Women are twice as likely as men to develop PD. One third to one half of patients will also suffer from agoraphobia. Other potential complications are a higher risk of substance abuse (perhaps as an attempt to self-medicate), suicide, and mitral valve prolapse. Because symptoms also overlap with many physical conditions, there is often an excessive use of medical services. PD typically follows a waxing and waning course but up to 20% of patients will experience a more chronic, persistent course.

PD consists of several components, including:



  • Panic attack (at least two episodes that are unexpected, spontaneous)



    • Limited symptoms


    • Full episodes


  • Anticipatory anxiety for at least 1 month that another episode will occur in certain places or situations


  • Phobic avoidance of the feared situational trigger(s)


  • Anxiety about serious medical problems

Table 4-1 lists common symptoms associated with a panic attack.


DIFFERENTIAL DIAGNOSIS

Comorbidity with other psychiatric disorders and overlapping symptoms is common (e.g., 50% to 60% of patients with PD will also meet criteria for major depressive disorder, many patients will experience panic symptoms during a depressive episode). In addition, a variety of other psychiatric and nonpsychiatric disorders may produce panic symptoms, including:



  • Substance-induced (e.g., caffeine intoxication, alcohol withdrawal)



  • Medical disorders (e.g., hyperthyroidism)


  • Other psychiatric disorders (e.g., major depression, posttraumatic stress disorder, specific phobia, social phobia)








TABLE 4-1 aSymptoms of a Panic Attack













































Shortness of breath/smothering sensations



Dizziness, unsteady feelings, or faintness



Palpitations/tachycardia



Trembling/shaking



Sweating



Choking



Nausea/abdominal distress



Depersonalization/derealization



Paresthesias



Flushes/chills



Chest pain or discomfort



Fear of dying



Fear of going crazy or doing something uncontrolled


aAt least four of these symptoms should be present to meet diagnostic criteria.


Therefore, a thorough history and physical examination should be conducted to rule out other potential causes.




NEUROBIOLOGY OF PANIC DISORDER

Environmental and biological factors predispose to the development of this disorder. For example, most symptomatic patients will report a major life stressor in the previous year. In addition, PD appears to have the highest level of family aggregation (i.e., almost a sevenfold increased risk) among the anxiety disorders. Twin studies also indicate that PD has the highest heritability of all the anxiety disorders.

The characteristic respiratory symptoms (e.g., dyspnea, rapid breathing) that often accompany panic attacks have led to different hypotheses, including:



  • Respiratory instability secondary to abnormal brain stem mechanisms



    • Hyperventilation syndrome


    • Increased respiratory variability


    • “False suffocation alarm”


  • Conditioned fear response



    • Driven by an oversensitive network involving the amygdala, prefrontal cortex, and hypothalamus


    • Physiological changes trigger panic attacks by contributing to the perception of anxiety

In part, on the basis of the putative mechanisms of action of various effective treatments for PD and imaging studies, abnormalities in neurotransmitter systems such as serotonin and γ-aminobutyric acid (GABA) have also been implicated.


TREATMENT OF PANIC DISORDER


Pharmacotherapy for Panic Disorder

While benzodiazepines (BZDs) have been used for decades to treat the symptoms of PD, they have largely been replaced by antidepressant agents.1 As with obsessive compulsive disorder (OCD), the selective serotonin reuptake inhibitors (SSRIs) are the recommended first-line drug strategy primarily due to their better safety-tolerability profiles (see Table 2-5 for more details regarding the adverse effects of antidepressants [ADs]). Table 4-2 lists the various classes of drugs frequently used to treat PD. Often, higher doses and longer durations of exposure (e.g., ≥12 weeks) are required to achieve optimal control of acute symptoms. Additionally, there is growing evidence that these agents are also effective in maintaining symptom control, preventing recurrence, and improving overall functioning in patients with PD.









TABLE 4-2 Medications for Treatment of Panic Disorder























































































Class/Generic Name


Common Trade Name


Usual Dose Range (mg/d)


Benzodiazepines


Alprazolam


Xanax


2-6


Alprazolam XR


Xanax XR


2-6


Clonazepam


Klonopin


1-2


SSRIs


Paroxetine


Paxil


40


Paroxetine CR


Paxil CR


40


Fluoxetine


Prozac


20


Sertraline


Zoloft


50


aCitalopram


Celexa


20-30


aEscitalopram


Lexapro


10


SNRIs


Venlafaxine ER


Effexor ER


75-225


aDuloxetine


Cymbalta


30-120


Tetracyclics


Mirtazapine


Remeron


7.5-45


Tricyclics


Imipramine


Tofranil


100-300


Clomipramine


Anafranil


25-150


MAOIs


aPhenelezine


Nardil


15-45


aTranylcypromine


Parnate


15-70


a Not approved by U.S. Food and Drug Administration.


SSRIs, selective serotonin reuptake inhibitors; SNRIs, serotonin norepinephrine reuptake inhibitors; MAOIs, monoamine oxidase inhibitors.

Only gold members can continue reading. Log In or Register to continue

Jul 8, 2016 | Posted by in PSYCHOLOGY | Comments Off on Panic Disorder
Premium Wordpress Themes by UFO Themes