The neurobiology of social phobia

Studies in the neurobiology of social phobia have used neuroendocrine, naturalistic and chemical challenges, pharmacological probes, neurotransmitter system measures, peripheral receptor binding and magnetic resonance measures. Studies of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid axes have been largely unrevealing; adrenaline, carbon dioxide, caffeine and yohimbine tests have provided mixed results; probe studies using L-dopa, clonidine and fenfluramine have provided some evidence of post-synaptic serotonergic abnormality; studies on platelet and lymphocyte binding have failed to distinguish social phobia from other groups; magnetic resonance imaging and magnetic resonance spectroscopy studies suggest possible differences between patients with social phobia and healthy controls in respect of dopamine, serotonin and second-messenger function. In aggregate, these studies have provided some neurobiological basis for separating social phobia from panic disorder and non-psychiatric healthy controls.