Intranasal oxytocin reduces attentional bias to food stimuli.

Attentional biases to food-related stimuli have been demonstrated in response to hunger as well as during restrained eating. Such biases are often associated with obesity, but healthy-weight individuals who do not self-report hunger have also demonstrated attentional biases to stimuli signalling food using laboratory-based cognitive tasks. Levels of the anorectic neuropeptide oxytocin are elevated by food intake and, when administered intranasally, oxytocin inhibits food intake in the laboratory. To investigate whether oxytocin can affect appetite via an action on attentional processes, 40 adults (29 women; mean age 24.0 years old) self-administered 24 IU of oxytocin or placebo intranasally. Forty minutes after administration, participants ate a small snack to maintain alertness and ameliorate deprivation-induced hunger before starting a computerized dot-probe attentional bias task that presented 180 trials of paired visual stimuli comprising neutral, food, social and/or romantic images (500 ms presentation time). Reaction times to probe stimuli that appeared after the offset of the visual images indicated a significant attentional bias to food pictures after placebo; this effect was significantly attenuated by oxytocin, p < .001. The effect of oxytocin on attentional bias to the food pictures was not altered by the type of stimulus paired with the food image, and was independent of BMI, age, sex, self-rated eating behaviour, and self-reported parental bonding; however, the effect was modulated by self-reported food cravings and trait stress. The findings support and extend previous work which has suggested that oxytocin can counteract attentional biases to food-related stimuli in a sample with anorexia by demonstrating the same effect for the first time in a cohort who do not have an eating disorder.

Subjective self-control and behavioural impulsivity coexist in anorexia nervosa.

OBJECTIVE: Anorexia nervosa (AN) has been associated with impulse regulation problems. This study investigated subjective and behavioural impulsivity in women with anorexia nervosa (n=15) and a control group (n=16). METHOD: A self-report measure (the impulsiveness, venturesomeness, and empathy questionnaire; I(7)) and two behavioural measures (a continuous performance task [CPT]; and a novel risk taking measure [Bets 16]) of impulsivity were used along with the Beck Depression Inventory (BDI). RESULTS: The AN group had elevated BDI scores and lower self-reported impulsiveness and venturesomeness scores, but they also displayed impulsive behaviour on the CPT (more errors of commission with faster reaction times). DISCUSSION: The coexistence, in AN, of self-reported self-control and behavioural impulsivity indicates that the relationship between impulsivity and disordered eating in AN is more complex than previously recognised and supports the view that self-awareness in AN is low.

Impulsivity, risk taking and recreational 'ecstasy' (MDMA) use.

The present study investigated characteristics of recreational drug users, especially 'ecstasy' (MDMA) users, in 254 undergraduates. All participants completed a drug history questionnaire (DHQ), the impulsiveness venturesomeness and empathy questionnaire, a novel risk-taking task (Bets16), and 59 also completed the tri-dimensional personality questionnaire (TPQ). DHQ responses allocated participants to five groups: non-drug controls, cannabis users, polydrug (no ecstasy) users, low (<20 occasions) ecstasy users and high (>20 occasions) ecstasy users. Eighteen percent of the sample had used ecstasy and of the ecstasy users, only one had not used other substances. A larger proportion of high ecstasy users had also used amphetamines, cocaine and LSD in comparison to the low ecstasy and non-ecstasy polydrug users. High ecstasy users typically took significantly more ecstasy tablets compared with low ecstasy users. Impulsiveness, venturesomeness and novelty seeking behaviour increased from the non-drug users to high ecstasy users. Ecstasy users (low and high) and polydrug (non-ecstasy) users had higher levels of impulsivity, venturesomeness and novelty seeking behaviour compared with non-drug users. Furthermore, high ecstasy users scored higher on the Bets16 risk-taking measure than non-drug users, cannabis users and low ecstasy users. The findings are discussed in relation to: (i) the possibility that increased impulsivity pre-dated drug use; and (ii) the possible link between impulsivity and the putative serotonergic neurotoxicity of ecstasy.