Background The brain undergoes major remodeling during adolescence, resulting in improved cognitive control and decision-making, and reduced impulsivity, components of behavior mediated in part by the maturing frontal lobe. Gamma-amino butyric acid (GABA), the main inhibitory neurotransmitter system, also matures during adolescence, with frontal lobe GABA receptors reaching adult levels late in adolescence. Thus, the objective of this study was to characterize in vivo developmental differences in brain GABA levels. Methods Proton magnetic resonance spectroscopy (MRS) was employed at 4 Tesla to acquire metabolite data from the anterior cingulate cortex (ACC) and the parieto-occipital (POC) cortex in adolescents (n=30) and emerging adults (n=20). Results ACC GABA/Cr levels were significantly lower in adolescents relative to emerging adults, whereas no age differences were observed in the POC. Lower ACC GABA/Cr levels were significantly associated with greater impulsivity and worse response inhibition, with relationships being most pronounced for ACC GABA/Cr and No-Go response inhibition in adolescent males. Conclusions These data provide the first human developmental in vivo evidence confirming frontal lobe GABA maturation, which was linked to impulsiveness and cognitive control. These findings suggest that reduced GABA may be an important neurobiological mechanism in the immature adolescent brain, contributing to the reduced, yet rapidly developing, ability to inhibit risky behaviors and to make decisions, which could compromise adolescent health and safety.

Objective Agitation and aggression are among the most frequent and disruptive behavioral complications of dementia that contribute to increased cost of care, hospitalization, caregiver burden, and risk of premature institutionalization. This current study examined the safety and efficacy of electroconvulsive therapy (ECT) as a treatment for behavioral disturbances in dementia. We hypothesized that ECT would result in reduced agitated and aggressive behaviors between baseline and discharge. Methods Twenty-three participants admitted to McLean Hospital (Belmont, MA) and Pine Rest Christian Mental Health Services (Grand Rapids, MI), with a diagnosis of dementia who were referred for ECT to treat agitation and/or aggression, were enrolled in the study. We administered the Cohen-Mansfield Agitation Inventory (CMAI)-short form, Neuropsychiatric Inventory (NPI)-Nursing Home Version, Cornell Scale for Depression in Dementia (CSDD), and the Clinical Global Impression Scale (CGI) at baseline, during, and after the ECT course. Results Regression analyses revealed a significant decrease from baseline to discharge on the CMAI (F(4, 8) =13.3; p=0.006) and NPI (F(4, 31)= 14.6; p<0.001). There was no statistically significant change in scores on the CSDD. The CGI scores on average changed from a rating of “markedly agitated/aggressive” at baseline to “borderline agitated/aggressive” at discharge. Treatment with ECT was well tolerated by most participants; discontinuation of ECT occurred for two participants due to recurrence of agitation and for three participants due to adverse events. Conclusions ECT may be a safe treatment option to reduce symptoms of agitation and aggression in patients with dementia whose behaviors are refractory to medication management.

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