Publications by authors named "Christopher T Wong"

Background: Acute care hospitals increasingly provide care for youth experiencing mental health crises while they await transfer for psychiatric hospitalization. To inform quality improvement efforts, we aimed to characterize hospitalists' perceptions of health care quality during pediatric mental health boarding and their experiences of moral distress in caring for this population.

Methods: In March 2021, we conducted a web-based survey of hospitalists who participate in the Pediatric Research in Inpatient Settings (PRIS) network.

View Article and Find Full Text PDF

Objective: Obesity is associated with impaired inhibitory control over food intake. We hypothesized that the neural circuitry underlying inhibition of food craving would be impaired in obesity. Here we assessed whether obese men show altered brain responses during attempted cognitive inhibition of craving when exposed to food cues.

View Article and Find Full Text PDF

The response to drugs of abuse is affected by expectation, which is modulated in part by dopamine (DA), which encodes for a reward prediction error. Here we assessed the effect of expectation on methylphenidate (MP)-induced striatal DA changes in 23 participants with an active cocaine use disorder (CUD) and 23 healthy controls (HC) using [C]raclopride and PET both after placebo (PL) and after MP (0.5 mg/kg, i.

View Article and Find Full Text PDF

To assess how tobacco smoking status affects baseline dopamine D2/D3 (D2R) receptor availability and methylphenidate-induced dopamine (DA) release, we retrospectively analyzed D2R availability measures of 8 current smokers, 10 ex-smokers, and 18 nonsmokers who were scanned with positron emission tomography and [C]raclopride, after administration of an injection of placebo or 0.5 mg/kg i.v.

View Article and Find Full Text PDF

The role of the protein kinase Akt1 in dopamine neurotransmission is well recognized and has been implicated in schizophrenia and psychosis. However, the extent to which variants in the gene influence dopamine neurotransmission is not well understood. Here we investigated the effect of a newly characterized variant number tandem repeat (VNTR) polymorphism in [major alleles: L- (eight repeats) and H- (nine repeats)] on striatal dopamine D2/D3 receptor (DRD2) availability and on dopamine release in healthy volunteers.

View Article and Find Full Text PDF

The extent to which cannabis is deleterious to the human brain is not well understood. Here, we test whether cannabis abusers (CA) have impaired frontal function and reactivity to dopaminergic signaling, which are fundamental to relapse in addiction. We measured brain glucose metabolism using PET and [(18)F]FDG both at baseline (placebo) and after challenge with methylphenidate (MP), a dopamine-enhancing drug, in 24 active CA (50% female) and 24 controls (HC; 50% female).

View Article and Find Full Text PDF

Objective: Dopamine mediates the rewarding effects of food that can lead to overeating and obesity, which then trigger metabolic neuroadaptations that further perpetuate excessive food consumption. We tested the hypothesis that the dopamine response to calorie intake (independent of palatability) in striatal brain regions is attenuated with increases in weight.

Method: We used positron emission tomography with [11C]raclopride to measure dopamine changes triggered by calorie intake by contrasting the effects of an artificial sweetener (sucralose) devoid of calories to that of glucose to assess their association with body mass index (BMI) in nineteen healthy participants (BMI range 21-35).

View Article and Find Full Text PDF

Objective: Brain dopamine dysfunction in attention deficit/hyperactivity disorder (ADHD) could explain why stimulant medications, which increase dopamine signaling, are therapeutically beneficial. However while the acute increases in dopamine induced by stimulant medications have been associated with symptom improvement in ADHD the chronic effects have not been investigated.

Method: We used positron emission tomography and [(11)C]cocaine (dopamine transporter radioligand) to measure dopamine transporter availability in the brains of 18 never-medicated adult ADHD subjects prior to and after 12 months of treatment with methylphenidate and in 11 controls who were also scanned twice at 12 months interval but without stimulant medication.

View Article and Find Full Text PDF

Dopamine signals through D1-like and D2-like receptors, which can stimulate or inhibit, respectively, neuronal activity. Here we assessed the balance between D1 or D2 receptor signaling in the human brain and how it is affected in alcoholism. Using PET, we measured the relationship between changes in dopamine and brain glucose metabolism induced by methylphenidate in controls and alcoholics.

View Article and Find Full Text PDF

Stimulant medications, such as methylphenidate, which are effective treatments for attention deficit hyperactivity disorder (ADHD), enhance brain dopamine signaling. However, the relationship between regional brain dopamine enhancement and treatment response has not been evaluated. Here, we assessed whether the dopamine increases elicited by methylphenidate are associated with long-term clinical response.

View Article and Find Full Text PDF

Subjects with binge eating disorder (BED) regularly consume large amounts of food in short time periods. The neurobiology of BED is poorly understood. Brain dopamine, which regulates motivation for food intake, is likely to be involved.

View Article and Find Full Text PDF

Although impaired inhibitory control is linked to a broad spectrum of health problems, including obesity, the brain mechanism(s) underlying voluntary control of hunger are not well understood. We assessed the brain circuits involved in voluntary inhibition of hunger during food stimulation in 23 fasted men and women using PET and 2-deoxy-2[(18)F]fluoro-D-glucose ((18)FDG). In men, but not in women, food stimulation with inhibition significantly decreased activation in amygdala, hippocampus, insula, orbitofrontal cortex, and striatum, which are regions involved in emotional regulation, conditioning, and motivation.

View Article and Find Full Text PDF

The neurobiological mechanisms underlying overeating in obesity are not understood. Here, we assessed the neurobiological responses to an Implantable Gastric Stimulator (IGS), which induces stomach expansion via electrical stimulation of the vagus nerve to identify the brain circuits responsible for its effects in decreasing food intake. Brain metabolism was measured with positron emission tomography and 2-deoxy-2[18F]fluoro-D-glucose in seven obese subjects who had the IGS implanted for 1-2 years.

View Article and Find Full Text PDF

Objective: The increased incidence of obesity most likely reflects changes in the environment that had made food more available and palatable. Here we assess the response of the human brain to the presentation of appetitive food stimuli during food presentation using PET and FDG.

Method: Metabolic changes in response to food presentation were done in 12 healthy normal body weight subjects who were food deprived before the study.

View Article and Find Full Text PDF

Background: The mechanisms underlying the gender differences in alcohol drinking behavior and alcohol's effects are poorly understood and may reflect gender differences in brain neurochemistry. Alcohol decreases glucose metabolism in the human brain in a pattern that is consistent with its facilitation of GABAergic neurotransmission. We compared the regional changes in brain glucose metabolism during alcohol intoxication between female and male subjects.

View Article and Find Full Text PDF

The cerebral mechanisms underlying excess food intake in obese subjects are poorly understood. We used PET and 2-deoxy-2[18F]fluoro-D-glucose to assess differences in regional brain metabolism between obese and lean subjects at rest. Brain metabolic images were analyzed using statistical parameter maps.

View Article and Find Full Text PDF