Neuroimaging studies depression

Advances in this area have perhaps been the most profound over the past 5 to 10 years, occurring as a result of imaging studies followed by focused postmortem studies of the brains of patients with both bipolar and unipolar depression. Neuroimaging studies of patients with familial pure major depression have identified neurophysiological abnormalities in multiple areas of the orbital and medial prefrontal cortex (PFC), the amygdala, and related parts of the striatum and thalamus. Some of these abnormalities appear to be state dependent (i.e., present only when the patient is clinically depressed), whereas other abnormalities appear to be trait dependent (i.e., present whether the patient is depressed or not) ( 27). 

Depression is not the only clinical condition in which placebo effects have been linked to changes in the brain. Changes in brain activity have also been shown in neuroimaging studies of placebo analgesics, the most influential of which was reported by a team of researchers led by Tor Wager, a neuroscientist at Columbia University who, at the time he conducted these studies, was a postgraduate student at the University of Michigan.39... 

Glucocorticoid receptors are present in a high density in the amygdala and neuroimaging studies have shown that the amygdala is the only structure in which the regional blood flow and glucose metabolism consistently correlate positively with the severity of depression. This... 

Preliminary Results of Neuroimaging Studies in Children and Adolescents with Depression... 

Table 10.1 summarizes the results of available pediatric neuroimaging studies in depressed patients. Given the limited amount of available data, published papers and professional presentations are reviewed. Two of the eight studies included seven or fewer depressed subjects, and two had no normal control comparisons. Results from the three largest-scale studies suggest that there are some neuroanatomical correlates of depression that may be evident across the life cycle (e.g., frontal lobe and amygdala volume changes), and others... 

TABLE 10.1. Neuroimaging Studies of Children and Adolescents with Major Depression... 

In this chapter we review extant data on the neurobiology of unipolar and bipolar depressive disorders in children and adolescents. A complement to two recent reviews (Kaufman and Ryan, 1999 Kaufman et ah, 2001), this chapter places primary emphasis on those studies in which neuroimaging techniques have been used. Unfortunately, such studies are few and far between. Preclinical models that have guided research on the neurobiology of affective disorders in adults are discussed, and, given the limits in the application of these models to juvenile samples, especially in the case of unipolar disorder, the need for more developmentally focused preclinical work is emphasized. 

Unipolar and bipolar depressive disorders in children and adolescents are serious conditions. The pathophysiology of these disorders is poorly understood. The new tools available through neuroimaging techniques will help to unravel the neuroanatomical systems involved in the onset and recurrence of these disorders. There is a need for more developmentally informed predinical research and more studies of the normal development of the neural systems implicated in emotional regulation. 

Drevets WC. Neuroimaging and neuropathological studies of depression implications for the cognitive-emotional features of mood disorders. Curr Opin Neurobiol 2001 11 240-249. 

---