Medial temporal N-acetyl-aspartate in pediatric major depression.

The medial temporal cortex (MTC) has been implicated in the pathogenesis of pediatric major depressive disorder (MDD). Eleven MDD case-control pairs underwent proton magnetic resonance spectroscopic imaging. N-acetyl-aspartate was lower in the left MTC (27%) in MDD patients versus controls. Lower N-acetyl-aspartate concentrations in MDD patients may reflect reduced neuronal viability.

Gray matter structural alterations in psychotropic drug-naive pediatric obsessive-compulsive disorder: an optimized voxel-based morphometry study.

OBJECTIVE: Although several magnetic resonance imaging (MRI) studies have been conducted in adults with obsessive-compulsive disorder (OCD), few studies have used voxel-based morphometry to examine brain structure, especially in psychotropic drug-naive pediatric patients. METHOD: MRI examinations of 37 psychotropic drug-naive pediatric OCD patients and 26 age- and sex-matched healthy volunteers were acquired on a 1.5 T MRI system, normalized to a customized template, and segmented with optimized voxel-based morphometry. RESULTS: Pediatric OCD patients had significantly more gray matter in regions predicted to differ a priori between groups, including the right and left putamen and orbital frontal cortex. Among patients, more gray matter in the left putamen and right lateral orbital frontal cortex correlated significantly with greater OCD symptom severity, but not with anxiety or depression. Manual region-of-interest measurements confirmed more gray matter in the orbital frontal cortex and putamen in patients compared to healthy volunteers. More anterior cingulate gray matter was evident among patients compared to healthy volunteers with regional volumetry but not with voxel-based morphometry. Regions of significantly less gray matter in OCD were confined to the occipital cortex and were not predicted a priori. CONCLUSIONS: Our results suggest that OCD is characterized by more gray matter in brain regions comprising cortical-striatal-thalamic-cortical circuits. These findings are consistent with functional neuroimaging studies reporting hypermetabolism and increased regional cerebral blood flow in striatal, anterior cingulate, and orbital frontal regions among OCD patients while in a resting state.

Amygdala and hippocampal volumes in familial early onset major depressive disorder.

BACKGROUND: Abnormalities in the amygdala and hippocampus have been implicated in the pathogenesis of major depressive disorder (MDD). To our knowledge, no prior study has examined amygdala-hippocampus anatomy in pediatric patients with familial MDD (at least one first degree relative with MDD). METHODS: Thirty-two psychotropic-naive patients with familial MDD, aged 8-21 years (12 males and 20 females), and 35 group-matched healthy participants (13 males and 22 females) underwent volumetric magnetic resonance imaging in order to evaluate hippocampal and amygdala volumes. RESULTS: Patients with familial MDD had significantly smaller left hippocampal (p = .007, effect size [d] = .44) and right hippocampal volumes (p = .025, d = .33) than controls. No differences were noted in amygdala volumes between groups (right: p > .05, left: p > .05). No correlations between hippocampal or amygdala volumes and demographic or clinical variables were noted. CONCLUSIONS: Reduced hippocampal volume may be suggestive of a risk factor for developing MDD.

Development and sexual dimorphism of the pituitary gland.

The pituitary gland plays a central role in sexual development and brain function. Therefore, we examined the effect of age and gender on pituitary volume in a large sample of healthy children and adults. Volumetric magnetic resonance imaging (MRI) was conducted in one hundred and fifty four (77 males and 77 females) healthy participants. Males were between the ages of 7 to 35 years (16.91+/-5.89 years) and females were 7 to 35 years of age (16.75+/-5.75 years). Subjects were divided into subgroups of age (7 to 9, 10 to 13, 14 to 17, 18 to 21, 22 and older) and sex (male/female). Pituitary gland volume differed between sexes when comparing the age groups (F=3.55, df=2, 143, p=0.03). Females demonstrated larger pituitary glands than males in the age 14 to 17 year old groups (p=0.04). Young (19 years and under) and old (20 years and older) females demonstrated a correlation between pituitary volume and age. Males did not show this relationship. These findings provide additional evidence for gender differences in the normative anatomy of the pituitary and may have relevance for the study of various childhood onset neuropsychiatric disorders in which pituitary dysfunction has been implicated.

Pituitary volume in treatment-naïve pediatric major depressive disorder.

BACKGROUND: Prior pilot investigation identified a larger pituitary gland volume (PGV) in pediatric patients with major depressive disorder (MDD) compared with healthy pediatric control subjects that was most prominent in boys with MDD. In this independent sample, we focus on gender differences in pituitary volume in a larger sample of pediatric patients with MDD. METHODS: Volumetric magnetic resonance imaging studies were conducted in 35 psychotropic drug-naïve children (15 boys, 20 girls), ages 8-17 years, and 35 case-matched healthy control subjects. RESULTS: The MDD boys had larger PGV (19%) compared with male control subjects. No significant diagnostic group differences in pituitary volume were observed in girls. Healthy boys had significantly smaller PGV (27%) than healthy girls, whereas MDD boys did not differ from girls with MDD. Nonfamilial (without a family history of mood disorder) boys with MDD had significantly larger PGV (35%) than male healthy control subjects and tended to have a larger PGV (27%) than familial (at least one first-degree relative with MDD) boys with MDD. Boys with familial MDD did not differ from control subjects. CONCLUSIONS: These findings provide new evidence of increased pituitary volume in psychotropic-naïve pediatric patients with MDD that seems to be more prominent in male patients with nonfamilial MDD.