Dieting to control body weight involves cycles of deprivation from palatable food that can promote compulsive eating. The present study shows that rats withdrawn from intermittent access to palatable food exhibit overeating of palatable food upon renewed access and an affective withdrawal-like state characterized by corticotropin-releasing factor-1 (CRF 1) receptor antagonistreversible behaviors, including hypophagia, motivational deficits to obtain less palatable food, and anxiogenic-like behavior. Withdrawal was accompanied by increased CRF expression and CRF 1 electrophysiological responsiveness in the central nucleus of the amygdala. We propose that recruitment of anti-reward extrahypothalamic CRF-CRF 1 systems during withdrawal from palatable food, analogous to abstinence from abused drugs, may promote compulsive selection of palatable food, undereating of healthier alternatives, and a negative emotional state when intake of palatable food is prevented.eating disorders ͉ obesity ͉ palatability ͉ palatable food dependence ͉ withdrawal F orms of obesity and eating disorders, similar to drug addiction, can be conceptualized as chronic relapsing conditions with alternating periods of abstinence (i.e., dieting to avoid ''forbidden'' palatable foods) and relapse (i.e., compulsive, often uncontrollable, eating of high-palatable foods) that continue despite negative consequences (1). Although the positive reinforcing properties of palatable foods are well known (2, 3), less attention has been given to their negative reinforcing properties (4-6), namely the increased probability of a behavioral response produced by removal of an aversive stimulus (e.g., intake of palatable food to relieve negative emotional states). Intermittent cycles of extended use of drugs of abuse can progressively lead to ''affective dependence,'' observed as a need for higher and/or more regular quantities of the drug to maintain a given emotional set point as well as a negative emotional state upon cessation of drug intake (7,8). Such affective withdrawal may maintain use and motivate relapse via the negative reinforcing properties of continuing and resuming drug use, respectively (7,8).Extrahypothalamic corticotropin-releasing factor (CRF) brain stress systems are putatively involved in the transition from drug use to dependence, during which intake of abused drugs becomes increasingly motivated by these negative, rather than positive, reinforcement mechanisms. CRF plays a motivationally relevant role in withdrawal syndromes for every major drug of abuse, including alcohol, nicotine, cocaine, opiates, amphetamines, and tetrahydrocannabinol (7,8). By analogy, repeated cycles of intermittent, extended access to highly palatable food were hypothesized to induce CRF system neuroadaptations similar to those seen in drug dependence models (4, 5, 9). ResultsIntermittent, extended access to palatable food progressively leads to undereating of less preferred diets when palatable food is not available and to overeating of palatable food upon renewed ...

Narcotic analgesics are commonly prescribed drugs in patients with chronic hepatitis C (CHC) infection. In vitro data have shown that morphine enhances hepatitis C virus replication in human hepatic cells, however the effect of narcotics on hepatitis C virus disease progression remains uncertain. The aim of this study was to evaluate the potential effects of narcotic analgesic use on the progression of hepatic fibrosis in patients with CHC infection. We identified CHC patients who had been seen at our institution and had undergone a liver biopsy between 1990 and 2005. Their charts were reviewed for the presence of narcotic analgesic and known risk factors for progression of hepatic fibrosis including male sex, age > or =40, obesity, diabetes, and alcohol abuse. All biopsy were reviewed and fibrosis scores were standardized using the Batts and Ludwig scoring system (stage 0 to 4). A total of 1147 evaluable patients were identified and 171 of these had narcotic analgesic use. In univariate analysis, narcotic analgesic use was associated with the presence of alcohol abuse (P<0.001), obesity (P=0.02), and advanced fibrosis defined as stage 3 to 4 fibrosis (P=0.02), but not with male sex or diabetes. In multivariate logistic regression analysis, obesity [odds ratio (OR) 1.68 (confidence interval (CI), 1.21-2.33)], alcohol abuse [OR 1.45 (CI, 1.04-2.02)], age > or =40 [OR 1.85 (CI, 1.22-2.89)], and diabetes [OR 2.43 (CI, 1.41-4.14)] all independently predicted advanced liver fibrosis but narcotic analgesic use did not [OR 1.71 (CI, 0.99-2.89)]. As the amount of narcotic analgesic use increased from no use, to <3 months use, to > or =3 months use, the frequency of obesity, alcohol abuse, and advanced fibrosis increased accordingly (P=0.005), suggesting that it is difficult to separate these known risk factors from narcotic use as the cause for advanced fibrosis in this population.