PSYCHOLOGY Etiology of Mental Dysfunction Neurobiological Theory of Anxiety Disorders

1. PSYCHOLOGYEtiology of Mental DysfunctionNeurobiological Theory of Anxiety Disorders Sources: Mental Health Nursing, Fontaine & Fletcher, 4th ed., Addison Wesley Longman, Inc., 1999 Psychiatric Mental Health Nursing, Fortinash & Holoday-Worret, Mosby-Year Book, Inc. 1996 Contemporary Psychiatric-Mental Health Nursing; Kneisl, Wilson & Trogoboff, Pearson Education Inc., New Jersey, 2004 Instructor: Doris O. Aghazarian, M.A., B.Sc.N., R.N.

2. Etiology of Anxiety Disorders(Source 1)CONCOMITANT DISORDERS • There is a high correlation between anxiety disorders and substance abuse. • As many as 50-60% of substance abusers have an anxiety disorder. • Typically, severe anxiety precedes substance abuse, although for some the abuse precedes the anxiety.

3. Etiology of Anxiety Disorders(Source 1)Concomitant disorders (cont´d) • People suffering from anxiety disorders ”self-medicate” with alcohol, not realizing that alcohol in fact increases anxiety. • It becomes a self-destructive cycle.

4. Etiology of Anxiety Disorders(Source 1)Concomitant disorders (cont´d) Frequently, depression follows the onset of an anxiety disorder. • Depression and anxiety disorders, it is thought, share a common biological predisposition, which may be activated by stress. • The depression caused by the results of anxiety may range from mild to severe, and suicide becomes a danger.

5. Etiology of Anxiety Disorders(Source 1)CAUSATIVE THEORIES NO SINGLE THEORY CAN ADEQUATELY EXPLAIN THE CAUSE AND MAINTENANCE OF ANXIETY DISORDERS. • THEY ARE BEST UNDERSTOOD AS A COMPLEX INTERACTION OF MANY THEORIES.

6. Etiology of Anxiety Disorders(Source 1)NEUROBIOLOGICAL THEORY • Some component of anxiety appear to run in families. • The exact role of genetic disposition is unknown at this time. • Some believe anxious individuals have an overly responsive autonomic nervous system related to a dysfunction of serotonin (5-HT) and norepinephrine (NE) neurotransmission.

7. Etiology of Anxiety Disorders(Source 1)Neurobiological theory (cont´d) • A hyperactive autonomic nervous system may be responsible for the characteristics panic levels of anxiety. • Research is continuing in the following areas: • A deficiency in certain receptors causing surges of NE • CNS abnormalities, particularly in the locus coeruleus of the pons, which inhibit the ability to moderate sensory input • An increased sensitivity to carbon dioxide, leading to rapid breathing and sensations of suffocation. (Panic attacks usually occur in places where CO2 concetrations are high: fresh air has a CO2 level of 200 parts per million. In cars the CO2 level reaches 750 ppm and as high as 900 ppm in elevators and planes. • Stimulants that alter NE transmission, e.g. caffeine and drugs

8. Etiology of Anxiety Disorders(Source 1)Neurobiological theory (cont´d) - It is believed that some biological vulnerability – when combined with certain psychological, social and environmental events – leads to the development of panic disorder. (Hedaya, 1996; Perna et al, 1996)

9. Etiology of Anxiety Disorders(Source 1)Neurobiological theory (cont´d) • Social phobia may be associated with decreased dopamine (DA) transmission related to a reduced number of DA synapses. • The enhancement of DA transmission leads to increased activity, novelty seeking and exploratory behaviour, all of which are the opposite of symptoms of social phobia. (Tiihonen, 1997)

10. Etiology of Anxiety Disorders(Source 1)Neurobiological theory (cont´d) • Research in obsessive-compulsive disorder is now focusing on genetic factors. • In this disorder, children and adults experience identical symptoms, whereas in most other mental disorders, children´s symptoms are quite different from those of adults. • Also, 50% of adults with OCD state that their symptoms began when they were children; only 5% of adults with other mental disorders report childhood onset.

11. Etiology of Anxiety Disorders(Source 1)Neurobiological theory (cont´d) • In 39% of women with OCD who have children, the onset occurred during pregnancy. • Of OCD sufferers 20% have a firs-degree relative with the same problem. • Father-son combinations are the most common.

12. Etiology of Anxiety Disorders(Source 1)Neurobiological theory (cont´d) • It is unlikely that the behaviour is learned, given the high level of secrecy. • Also, children and parents may have very different rituals. (Pauls, 1995; Rapoport, 1989)

13. Etiology of Anxiety Disorders(Source 1)Neurobiological theory (cont´d) • Increased activity in the frontal lobes and basal ganglia has been demonstrated through PET (positron emission tomography) scans, which measure glucose metabolism in different areas of the brain. • PET scans provide some evidence of neurological deficit in some individuals suffering from OCD.

14. Etiology of Anxiety Disorders(Source 1)Neurobiological theory (cont´d) • The abnormality apparently lies in a pathway that links the frontal lobes of the cerebral cortex with the basal ganglia. • Heightened activity in the cortex may reflect obsessional thinking, while compulsions may originate in the basal ganglia where body movements are planned and executed. (Eisenberg, 1995, Greenberg et al, 1997)

15. Etiology of Anxiety Disorders(Source 1)Neurobiological theory (cont´d) • There appear to be biological changes in PTSD that illustrate the influence of psychological events on neurobiology. • When high levels of adrenaline and other stress hormones are circulating, memory traces are deeply imprinted. • These are then reactivated as if the traumatic event were actually occurring.

16. Etiology of Anxiety Disorders(Source 1)Neurobiological theory (cont´d) • Traumatic nightmares can occur in stages of sleep in which people do not ordinarily dream. • Thus, traumatic memories appear to be based in altered neurophysiological organization. (Reeves and Ellison, 1996)

17. Etiology of Anxiety Disorders(Source 2)Neurobiological theory (cont´d) • In the section entitled BIOLOGIC MODEL (Source 2) it is stated that: • Roots of the biologic model for anxiety disorders date back to the 19th century writings of Charles Darwin. • In the early 20th century investigators linked the endocrine system with emotions, initially by establishing the relationship of the adrenal medulla in production of epinephrine, resulting in the flight or flight response theory.

18. Etiology of Anxiety Disorders(Source 2)Neurobiological theory (cont´d) • Seyle built on this work after WWII. • Seyle expanded the notion that the endocrine system and the central nervous system (CNS), particularly the hypothalamus and pituitary gland, have a reciprocal relationship. • At the same time important advances were made in investigations of the autonomic nervous system (ANS) in regulating cardiovascular, gastrointestinal and motor responses, showing the ANS to be responsive to environmental stimuli, including emotional states.

19. Etiology of Anxiety Disorders(Source 2)Neurobiological theory (cont´d) • Today, psychopharmacological interventions target the serotonin, noradrenergic and GABA systems primarily. • (See: Gamma-aminobutyric acid handout. http://en.wikipedia.org/wiki/GABA or just type GABA in Google.)

20. Etiology of Anxiety Disorders(Source 3)Neurobiological theory (cont´d) • In Source 3, all theories are discussed under the general heading of: BIOPSYCHOSOCIAL THEORIES. The neurobiological theory is seen as only part of the theory and is discussed under two separate headings, these being: BIOLOGIC FACTORS & GENETIC THEORIES.

21. Etiology of Anxiety Disorders(Source 3)Neurobiological theory (cont´d) • BIOLOGIC FACTORS • A major research question that remains unanswered is: Are the physiologic imbalances a cause or a result of the anxiety disorder?

22. Etiology of Anxiety Disorders(Source 3)Neurobiological theory (cont´d) • During the ”Decade of the Brain” (the 1990s), research efforts were undertaken to determine a pysiologic basis for mental disorders. • Much of the research findings indicate biologic changes in the brains of individuals experiencing anxiety disorders.

23. Etiology of Anxiety Disorders(Source )Neurobiological theory (cont´d) • Some of the findings are: • Drugs that increase the activity of the locus ceruleus have been found to cause panic attacks; drugs that inhibit the activity of the locus ceruleus block panic attacks. • Tricyclic antidepressant medications stabilize the locus ceruleus and noradrenergic system; thus, they are sometimes useful in alleviating the symptoms associated with panic attack. (Kaplan & Sadock 2000)

24. Etiology of Anxiety Disorders(Source 3)Neurobiological theory (cont´d) • The brain´s benzodiazepine (BZD) receptor system is especially sensitive to BZD drugs. The BZDs enhance the anction of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter. With the administration of GABA, or dugs that potentiate GABA, anxiety is reduced. On the other hand, drugs that inhibit the activity of GABA increase anxiety. (Kaplan & Sadock 2000). GABA may have a slight tranquilizing effect. (Bourne 2001)

25. Etiology of Anxiety Disorders(Source 3)Neurobiological theory (cont´d) • Structural changes have been discovered in the brains of people with PTSD. Specifically, atrophy of the hippocapus was shown in the brains of male Vietnam combat veterans. (Sapolsky 2000). The hippocampus is the area of the brain that regulates memory formulation and retention.

26. Etiology of Anxiety Disorders(Source 3)Neurobiological theory (cont´d) • Changes in another area of the brain, the amygdala, have been noted in people with OCD and other anxiety disorders. (Szesko, et al., 1999). The amygdala is the site in the brain that controls fear responses.

27. Etiology of Anxiety Disorders(Source 3)Neurobiological theory (cont´d) • Magnetic resonance imaging (MRI) findings show that those subjects with panic disorder had significantly smaller temporal lobe volume than normal subjects (Vythilingam et al., 2000)

28. Etiology of Anxiety Disorders(Source 3)Neurobiological theory (cont´d) • The reason why females have higher rates than males in males in most anxiety disorders is unclear, although some theories have implicated the gonadal steroids (U.S. Public Health Service, 2000)

29. Etiology of Anxiety Disorders(Source 3)Neurobiological theory (cont´d) • Lactic acid levels are higher in some individuals experiencing panic attacks. • Lactic acid may actually precipitate anxiety in some people. (Bourne, 2001).

30. Etiology of Anxiety Disorders(Source 3)Neurobiological theory (cont´d) • Among substances that increase anxiety levels are caffeine and nicotine. • Caffeine stimulates the CNS and increases NE production, producing the same physiologic arousal experienced by exposure to stress. Caffeine causes some people to remain in a chronically tense, aroused condition. • Nicotine is suspected to trigger panic attacks. It is a strong stimulant and causes increased physiologic arousal, vasoconstriction and hypertension. Nicotine consumers tend to sleep less well than nonsmokers.

31. Etiology of Anxiety Disorders(Source 3)Neurobiological theory (cont´d) • Genetics:- • Research evidence indicates that a familial predisposition for anxiety disorders may exist. • According to twin studies, there is a genetic factor in OCD and panic disorder. • Firs-degree relatives of people with panic disorder are 4-7 times more likely to develop panic disorder. • In approximately 25% of individuals with GAD there is a family history of the disorder.

32. Next: Other theories of anxiety disorders • Intrapersonal • Interpersonal • Cognitive • Learning • Behavioural • Humanistic • Continuum • Feminist NOTE THAT THEY MAY OVERLAP