14 Imaging Brain imaging represents a tool to characterize state and trait markers, also in disorders with an episodic course such as schizophrenia and bipolar disorder. An integrated approach to support diagnostic processes may lead to a more accurate classification of depression. 11 Results of functional magnetic resonance imaging (fMRI) indicate that both gray and white matter have diagnostic and prognostic potential in major depression and may provide an initial step towards the use of markers to predict efficacy of pharmacologic Inhibitors,research,lifescience,medical treatment.65 Besides structural analyses, positron emission tomography

(PET) and single -photon emission computed tomography (SPECT) are used to identify alterations of neurotransmitters and their respective receptors in specific regions of the brains. Magnetic resonance spectroscopy (MRS) literature supports the presence of brain metabolic alterations in relation to individual mood state, An analysis of 31P-MRS studies regarding brain energetic status and phospholipid metabolism provided support for state-specific alterations in bipolar Inhibitors,research,lifescience,medical disorder.66 More generally, evidence for an abnormal brain energy metabolism in mood disorders was found. Metabolic aberrations

may be intrinsic since, for example, brain intracellular pH determined Inhibitors,research,lifescience,medical by 31P-MRS is decreased in medication-free bipolar patients in manic, depressed, and euthymic mood states.12 Anxiety, and in Inhibitors,research,lifescience,medical particular panic disorder, has been extensively investigated to link episodic PF-04691502 in vivo pathological symptoms to underlying

biological mechanisms. It is hypothesized that respiratory dysregulation persists as a trait finding, also in the asymptomatic state,67 Patients with panic disorder are susceptible to panic attacks precipitated by challenges like sodium lactate infusion, carbon dioxide inhalation, and hyperventilation (Table III). Intravenous infusion of 0. 5 mol/L sodium lactate with 70 mL/kg body weight produces marked physiologic and psychologic symptoms in panic Inhibitors,research,lifescience,medical patients but less frequently in healthy controls.58 Also in 1-h MRS studies lactate infusion was used as a physiological challenge to investigate brain metabolism. When the distribution of lactate increases was assessed, abnormal brain lactate increases were estimated as tissue-based due ADP ribosylation factor to brain metabolic mechanisms. However, persistent brain lactate rises in panic patients during treatment with, eg, fluoxetine or gabapentin, indicate that brain lactate increases are possibly independent of metabolic challenges, which questions their suitability as markers.66 Only a few fMRI studies have investigated the brain activation patterns following CCK4 administration. CCK4-induced anxiety was accompanied by strong and robust activation in various areas. Analysis for placebo and anticipatory anxiety generated no significant differences, and overall functional responses did not differ between panickers and nonpanickers.