These findings provide further evidence that the pathophysiology of BD involves impairment in the DLPFC. Our findings can be interpreted as evidence for reduced cellular energy and phospholipid metabolism, consistent with the hypothesis of mitochondrial dysfunction in BD.

These findings provide fresh evidence for abnormalities in the striatum of medication-naïve pediatric MDD patients and suggest the possible involvement of the striatum in the pathophysiology of MDD.

Our results suggest that abnormal OFC gray matter volumes are not a pervasive characteristic of BD, but may be associated with specific clinical features of the disorder.

Imaging studies indicate smaller orbitofrontal cortex (OFC) volume in mood disorder patients compared with healthy subjects. We sought to determine whether child and adolescent patients with bipolar disorder have smaller OFC volumes than healthy controls. Fourteen children and adolescents meeting DSM-IV criteria for bipolar disorder (six males and eight females with a mean age ± S.D. = 15.5 ± 3.2 years) and 20 healthy controls (11 males and nine females with mean age ± S.D. = 16.9 ± 3.8 years) were studied. Orbitofrontal cortex volume was measured using magnetic resonance imaging. Male bipolar patients had smaller gray matter volumes in medial (p = 0.044), right medial (0.037) and right (p = 0.032) lateral OFC subdivisions compared to male controls. In contrast, female patients had larger gray matter volumes in left (p = 0.03), lateral (p = 0.012), left lateral (p = 0.007), and trends for larger volumes in right lateral and left medial OFC subdivisions compared with female controls. Male patients exhibit smaller gray matter volumes, while female patients exhibit larger volumes in some OFC sub-regions. Gender differences in OFC abnormalities may be involved in illness pathophysiology among young bipolar patients. No neuroimaging studies utilizing a region-of-interest approach have examined OFC volumes in patients with bipolar disorder. The purpose of this study was to investigate possible structural abnormalities of the OFC and its subdivisions in child and adolescent bipolar disorder patients compared to healthy controls. Based on the previous findings in mood disorder patients, we hypothesized smaller OFC volumes in child and adolescent bipolar individuals. KeywordsFourteen children and adolescents (mean age ± S.D. = 15.5 ± 3.2 years, age range = 10-21 years; six males and eight females; 14 Caucasian; 11 bipolar type I, 2 bipolar type II, 1 bipolar NOS; 12 right handed) diagnosed with DSM-IV bipolar disorder were studied. Twelve patients were euthymic and two were depressed at the time of the study. The patients had mean illness duration of 3.6 years, and the mean age at onset was 11.9 years. Ten patients were receiving treatment for bipolar disorder (six on lithium, one on valproate, and three on lithium and valproate). Twenty healthy controls (mean age ± S.D. = 17 ± 3.9 years, range: 10-21 years, 11 males and nine females; 19 right handed) were recruited. Healthy controls were excluded if they had any DSM-IV axis I disorders, any first degree relatives with a history of psychiatric disorders, or any current serious medical problem. Psychiatric diagnoses were determined through the schedule for affective disorders and schizophrenia for school-age children-present and life version [9], for Children up to 17-years-old, or the structural clinical interview for DSM-IV (American Psychiatric Association, 1994), for subjects of 18-year-old or older. The pubertal development of all subjects was measured using the Petersen pubertal development scale [15]. Written informed consent was obtained from all study par...

BP subjects have lower NAA levels in the left DLPFC compared to healthy subjects, suggesting neuronal dysfunction in this region.