A positron emission tomography study of nigro-striatal dopaminergic mechanisms underlying attention: implications for ADHD and its treatment.

Through the combined use of (18)F-fallypride positron emission tomography and magnetic resonance imaging this study examined the neural mechanisms underlying the attentional deficits associated with attention deficit/hyperactivity disorder and their potential reversal with a single therapeutic dose of methylphenidate. Sixteen adult patients with attention deficit/hyperactivity disorder and 16 matched healthy control subjects were positron emission tomography and magnetic resonance imaging scanned and tested on a computerized sustained attention task after oral methylphenidate (0.5 mg/kg) and placebo administration in a within-subject, double-blind, cross-over design.

Atomoxetine improved response inhibition in adults with attention deficit/hyperactivity disorder.

Background: Atomoxetine, a highly selective noradrenaline reuptake inhibitor (SNRI), shows efficacy in the treatment of attention-deficit/hyperactivity disorder (ADHD). Compared with psychostimulants, atomoxetine has a distinct mode of brain action and potentially lower addictive potential. Studies have yet to assess whether atomoxetine improves cognition following a single oral dose in ADHD.

Lack of deleterious effects of buspirone on cognition in healthy male volunteers.

Buspirone is a serotonin 5-HT(1A) receptor agonist licensed for the treatment of anxiety. Other anxiolytic drugs such as benzodiazepines show significant sedative and other unwanted effects on cognition. Studies to date have yet to investigate cognitive effects of buspirone using well-validated computerized tests.

Questionnaire ratings of attention-deficit/hyperactivity disorder (ADHD) in adults are associated with spatial working memory.

Objective: Data related to brain function may have the potential to improve the reliability and validity of assessments for the aetiologically and clinically heterogeneous syndrome of attention-deficit/hyperactivity disorder (ADHD). This study investigated associations between questionnaire assessments of behavioural features of adults with ADHD and an aspect of neurocognitive performance which has been reported to be impaired in adults with ADHD.

Methods: Fifty-nine adult patients with a DSM-IV diagnosis of ADHD, and their informants, completed questionnaires related to aspects of severity of ADHD.

Association between response inhibition and working memory in adult ADHD: a link to right frontal cortex pathology?

Background: We sought to assess the relationship between response inhibition and working memory in adult patients with attention-deficit/hyperactivity disorder (ADHD) and neurosurgical patients with frontal lobe damage.

Methods: The stop-signal reaction time (SSRT) test and a spatial working memory (SWM) task were administered to 20 adult patients with ADHD and a group of matched controls. The same tasks were administered to 21 patients with lesions to right frontal cortex and 19 patients with left frontal lesions.

Characteristics of neuronal lipofuscin in the superior temporal gyrus in Alzheimer's disease do not differ from non-diseased controls: a comparison with disease-related changes in the superior frontal gyrus.

Neuronal lipofuscin characteristics in the superior temporal gyrus from 21 patients with Alzheimer's disease (AD) and from 18 age-matched non-diseased subjects were compared with previously reported findings from the superior frontal gyrus. A discriminant function analysis of lipofuscin characteristics in the superior temporal gyrus did not provide a significant predictive level for cases whose diagnoses were correctly classified (56.4%, P=0.

Neurocognitive effects of methylphenidate in adult attention-deficit/hyperactivity disorder.

Rationale: Features of childhood attention-deficit/hyperactivity disorder (ADHD) often persist into adulthood. It has been shown that adult ADHD is associated with various neurocognitive deficits, including impairments in spatial working memory (SWM) and attention. It is not known whether these deficits are ameliorated by methylphenidate in adult ADHD.

Modafinil improves cognition and response inhibition in adult attention-deficit/hyperactivity disorder.

Background: Modafinil, a novel cognitive enhancer, has a clinical profile similar to conventional stimulants such as methylphenidate, despite a seemingly different mechanism of action. Modafinil selectively improves neuropsychological task performance in healthy volunteers, possibly through improved inhibitory control. We examined whether modafinil induced similar improvements in adults with attention-deficit/hyperactivity disorder.

Associations of the severity of depressive disorders in women with psychogenic low weight.

Background: Depressive disorders are common in patients with anorexia nervosa (AN). Although depression with AN has been considered to be mainly secondary to the features of AN, other characteristics of such patients may also be causal, as personality disorders (PDs) often occur with AN and there are indications that PDs are causal factors for some depressive disorders. This study examined associations of the severity of depressive disorders in patients with low weight and a history of full or partial AN, to determine which characteristics of patients with AN are candidates as causal factors for depression in this context.

Impulsivity in patients with borderline personality disorder.

This study investigated features of impulsivity in patients with borderline personality disorder (BPD) using the self-report Attention-Deficit Scales for Adults (ADSA) and computer-administered neurocognitive tasks. Forty-one patients with DSM-III-R BPD and 35 nonclinical control subjects were assessed by the ADSA, the National Adult Reading Test, and two computerized tasks mediated by the frontal lobes. Mean scores for seven ADSA scales (six of which relate to aspects of impulsivity) were significantly higher in the patient group compared with the control group.

Relative lack of cognitive effects of methylphenidate in elderly male volunteers.

Rationale: Methylphenidate, a dopaminergic and noradrenergic reuptake inhibitor, has been shown in young, healthy adult volunteers to produce pronounced effects on working memory and sustained attention. We were interested in assessing whether similar improvements could be conferred upon elderly volunteers in order to gain a more complete understanding of the effects of age on monoaminergic manipulations of working memory and attention, as well as to explore the potential for pharmacological intervention in attention and executive dysfunction disorders in this age group.

Objectives: The main aim of the study was to characterise the dose-related effects of methylphenidate on a range of neuropsychological functions in elderly healthy volunteers.

Impaired visual discrimination learning in anorexia nervosa.

The primate dopamine system is involved in appetitively motivated behaviours, including certain forms of learning, for example, visual discrimination learning. Furthermore, food restriction in animals and anorexia in humans is associated with impaired dopamine signaling. Based on this, we hypothesized that patients with anorexia nervosa (AN) would show a deficit in visual discrimination learning.

Cognitive enhancing effects of modafinil in healthy volunteers.

Rationale: Modafinil, a novel wake-promoting agent, has been shown to have a similar clinical profile to that of conventional stimulants such as methylphenidate. We were therefore interested in assessing whether modafinil, with its unique pharmacological mode of action, might offer similar potential as a cognitive enhancer, without the side effects commonly experienced with amphetamine-like drugs.

Objectives: The main aim of this study was to evaluate the cognitive enhancing potential of this novel agent using a comprehensive battery of neuropsychological tests.