Biological theories of panic; Noradrenergic theory
• Redmond (1981): stimulation locus coeruleus produced fear response in
monkeys
• Efferent axons of locus coeruleus that project to the hypothalamus are of
special significance for panic disorder (Charney & Heiniger, 1986)-
>influence on HPA-axis
• Administration of the noradrenergic antagonist yohimbine produced panic
attacks in panic disorder ( Abelson et al. 1992)
• Dysregulation (hyperactive) of noradrenergic system in panic disorder
(Coplan et al., 1997)
• Desynchronization of noradrenergic system and HPA axis possible but not
completely successful (Coplan et al. 1995)
Biological theories of panic; Serotonergic theory
• Dysfunctional neurotransmission at the serotonin receptors (5HT1A) may result in
anxiety or avoidant behavior (Deakin 1996)
• Activation of HPA Axis in panic disorder, may contribute to disruption of
hippocampal 5HT1A
neurotransmission (Lesch and Lerer 1991)
• Aberrant noradrenergic- serotonergic function (Boyer 1995)
• Serotonin depletion resulted in increased minute ventilation in panic disorder
patients
unaltered ventilatory function in controls (Kent et al., 1996)
Biological theories of Panic; GABAergic Theory
• GABA = inhibitory neurotransmitter
• Benzodiazepines increase function of GABA
• global decrease in benzodiazepine binding
• with a peak decrease in orbitofrontal cortex, and insula, hippocampus in panic
disorder patients compared to healthy controls (Malzia et al., 1998)
• Injection of sodium lactate (panicogen) led to panic-like response in
GABA-blocked rats only (Shekhar 2006)
• Interaction GABA-glutamate interrupted in panic disorder
Role of Panicogens in Panic Disorders
= substances that can induce panic attacks
• substances that influence HPA Axis
Yohimbine (noradrenaline increase)
coffein: adenosinergic (inhibitory) receptor antagonist
• Substances that influence lactate metabolism
sodium lactate, sodium bicarbonate, carbon dioxide
Role of Genetics in the Pathogenesis of Panic Disorder
• Twin studies have attributed 30-40% of the variance for the liability to develop
panic disorder to genetic factors (Kendler et al., 2001; Scherrer et al. 2000)
• highly significant association between panic disorder in probands
and first degree relatives (Hettema et al. 2001)
• cholecystokinin, adenosine 2A, MAO A, and COMT genes.
Psychological Theories of Panic Disorder
• Dynamic Model:
panic attack = expression of an intense unconscious conflict (Bush et al. 1999)
core conflict of depencency and inadequacy (Shear et al. 1993)
Contemporary dynamic models: integration of biological and developmental stressors
(Milrod et al. 2004)
• Cognitive Behavioral Models
• Anxiety Sensitivity
Theoretical perspective: cognitive factors
Anxiety sensitivity (Reiss and Mc Nally (1985)
• Core fear toward anxiety and its associated somatic symptoms
• Measured by anxiety sensitivity index
(Reiss et al. 1986)
• Significant predictor of the onset of panic in different patient populations
(e.g Ehlers 1995, Hayward et al. 2000; Maller and Reiss 1992)
Hyperventilation & Respiratory Theories
• Ley (1985): hyperventilation theory : hyperventilation causes panic attacks
• Klein (1993): false suffocation alarm model: hyperventilation avoid panic
attacks