Secondary sexual characteristics convey information about reproductive potential. In the same way that facial symmetry and masculinity, and shoulder-to-hip ratio convey information about reproductive/genetic quality in males, waist-to-hip-ratio (WHR) is a phenotypic cue to fertility, fecundity, neurodevelopmental resources in offspring, and overall health, and is indicative of “good genes” in women. Here, using fMRI, we found that males show activation in brain reward centers in response to naked female bodies when surgically altered to express an optimal (∼0.7) WHR with redistributed body fat, but relatively unaffected body mass index (BMI). Relative to presurgical bodies, brain activation to postsurgical bodies was observed in bilateral orbital frontal cortex. While changes in BMI only revealed activation in visual brain substrates, changes in WHR revealed activation in the anterior cingulate cortex, an area associated with reward processing and decision-making. When regressing ratings of attractiveness on brain activation, we observed activation in forebrain substrates, notably the nucleus accumbens, a forebrain nucleus highly involved in reward processes. These findings suggest that an hourglass figure (i.e., an optimal WHR) activates brain centers that drive appetitive sociality/attention toward females that represent the highest-quality reproductive partners. This is the first description of a neural correlate implicating WHR as a putative honest biological signal of female reproductive viability and its effects on men's neurological processing.
Citation: Platek SM, Singh D (2010) Optimal Waist-to-Hip Ratios in Women Activate Neural Reward Centers in Men. PLoS ONE 5(2): e9042. https://doi.org/10.1371/journal.pone.0009042
Editor: Henry Harpending, University of Utah, United States of America
Received: December 9, 2009; Accepted: January 18, 2010; Published: February 5, 2010
Copyright: © 2010 Platek, Singh. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This work was supported by a faculty induction award from the University of Liverpool and a grant from the Pioneer Fund. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Variations in men's facial (e.g., symmetry, masculinity) and body (e.g., shoulder-to-hip ratio) morphology are related to women's ratings of attractiveness. Specifically, women tend to rate more symmetrical and masculine faces, and higher SHR as attractive during fertile phases of their menstrual cycle and for short-term mating partners, , , , , , . Several recent findings, , ,  demonstrate that faces that are rated as attractive activate neural reward substrates in females, and that this neural activation is partly modulated by hormonal status of women. These findings support the hypothesis that men's facial and body morphology serves as an honest biosignal to genetic fitness.
Women have a larger proportion of fat stores in comparison to non-human female primates and men. Prior to puberty, a sexual dimorphism in fat distribution is not apparent, however, in post-menarche women estrogen inhibits storage of fat around abdominal areas and fat is stored in the gluteofemoral (thighs and buttock) region. Women have a lower waist-to-hip ratio (WHR) than men and men's preference for lower WHR, or hour-glass figures, appears to be cross-cultural, c.f.,  and adaptive because WHR is positively correlated with fecundity, levels of the reproductive hormones estradiol and progesterone, higher likelihood of conception, and availability of neurodevelopmental resources for offspring, but negatively correlated with lower likelihood of illnesses such as heart disease and various cancers, and lower incidence of depression. Differences in WHR can also be used to index pregnancy and the capacity for unencumbered childbirth. Consequently, it's been hypothesized that distribution of body fat represents a secondary sexual characteristic that, in the same way variation in men's facial and body morphology does, can influence ratings of attraction and fecundity (see also for arguments regarding female BMI).
Here 14 men (Mage = 25.21, S.D. = 6.30) were scanned using fMRI while making attractiveness ratings to randomly and individually presented pictures (one from the rear and one from an oblique rear position for each woman) of seven naked female bodies prior to and after recovery from an elective cosmetic surgical procedure to reconfigure and optimize WHR. All participants provided written informed consent and the study was approved by the University of Liverpool School of Biological Sciences committee on research ethics.
Stimuli were a sample of seven images taken from those used in another study . Images were presented in both the rear and oblique rear position (see ). Images were presented 15 times for 1 second with a variable interstimulus (2–15 s) interval to maximize jittering using Neurobehavioral Systems Presentation. Each participant saw each of the 14 different images in random order. Participants were asked to respond to the attractiveness of the images by using a 5 button fMRI-comaptible response pad (MR technologies). Order of button anchor (most attractive/least attractive) was randomized across subjects.
Data were collected using a Siemens Trio 3T scanner using gradient-echo T2*-weighted echo-planar images (EPI) to measure blood-oxygen-level-dependent (BOLD) contrasts. For each participant approximately 225 volumes were collected with an interleaved acquisition, a slice thickness of 2 mm, at a TR of 2.75 s, TE of 30 ms, and a resolution of 3.5×3.5 mm for each participant. Slices were tilted to 30 degrees from horizontal to maximize image quality in areas near susceptibility field gradients. All participants also underwent high-resolution structural scanning with a standard MP-RAGE sequence (176 1 mm voxel saggital slices, TR = 2040 ms, TE = 5.57 ms, FoV = 256, flip angle = 8°). While being scanned participants were asked to make explicit ratings of attractiveness to naked female body images  presented for 1 second (ISI randomization optimized for jitter 2–15 seconds). Ratings were made on a 5-point scale from very unattractive to very attractive (counterbalanced for which finger anchored each end of the attractiveness scale).
fMRI data were analyzed using general linear modeling and mixed effects analysis implemented in FEAT-FSL. We hypothesized that if WHR represents a cue to genetic quality then, similar to symmetry and masculinity in male faces, bodies that represent optimal WHR would activate neural reward substrates.
In order to determine whether the WHR surgical procedure had an effect on brain activation we first computed a contrast between pre-surgical and post-surgical bodies. Relative to viewing pre-surgical bodies, viewing post-surgical bodies revealed activation in right orbital frontal cortex (OFC) (Z = 4.11, p<.01 cluster corrected), lateral occipital cortex (Z = 3.82, p<.01 cluster corrected), and the anterior cingulate gyrus (Z = 3.71, p<.01) (Fig. 1a–b). Because the OFC has been associated with reward evaluation we created a bilateral OFC region of interest (ROI) mask to investigate the extent of activation in this area specifically. This analysis revealed that post-surgical images activated the left (Z = 3.59, p<.01) and the right (Z = 3.77, p<.01) OFC, but pre-surgical images did not (Fig. 2). An ROI of activation in bilateral amygdala, another area often associated with reward processing, , ,  and recently associated with implicit social judgment making,  revealed no voxels survived statistical threshold for pre- or post-surgical bodies. This finding demonstrates that changes associated with cosmetic surgery (aimed at optimizing female WHR) have specific effects on men's OFC, an area of the brain that is associated with evaluations of rewards.
(a) Statistical parametric map for contrast post-surgical versus pre-surgical bodies showing activation in anterior cingulate cortex and (c) right orbital frontal cortex at cluster corrected threshold of 3.0, p<.01.
We then regressed each woman's change in BMI and WHR between pre-surgery and post-surgery onto the participants' brain activation to determine how changes in BMI and WHR differentially affected the brains of men. While changes in BMI only revealed activation in visual brain substrates (right lingual gyrus Z = 2.72, p<.001 uncorrected; left fusiform gyrus Z = 2.25, p<.001 uncorrected; and right lateral occipital cortex Z = 2.21, p<.001 uncorrected) (Fig. 3a), changes in WHR revealed activation in the right para-anterior cingulate gyrus (Z = 2.58, p<.001 uncorrected) (Fig. 3b). This finding suggests that changes in BMI activate low-level visual areas that are tuned to noticing variations in body configuration, but not involved in the aesthetic evaluation of the body. On the other hand, changes in WHR activated the anterior paracingulate gyrus, which has been associated with reward processing, , social evaluation and decision-making, , and responses under uncertainty and adaptive personal significance.
(a) Statistical parametric map showing activation in visual areas to changes in BMI. (b) Activation to changes in WHR in the anterior paracingulate gyrus. (parametric analysis, p<.001 uncorrected).
Lastly, we regressed each participant's idiosyncratic ratings of attractiveness on their brain activation to post- minus pre-surgical bodies to investigate how explicit ratings of body attractiveness predict brain activation. This revealed activation in various forebrain structures including the left (Z = 3.40, p<.001 uncorrected) and right (Z = 4.30, p<.001 uncorrected) OFC, left putamen (Z = 3.70, p<.001 uncorrected), left nucleus accumbens (Z = 4.22, p<.001 uncorrected), left (Z = 4.93, p<.001 uncorrected), right (Z = 3.90, p<.001 uncorrected) caudate, and right thalamus (Z = 3.47, p<.001 uncorrected) (Fig. 4). This activation pattern, particularly activation of the nucleus accumbens, suggests that attractiveness ratings were associated with activation in neural reward centers, , , , , , , , , ,  that have also been associated with drug/alcohol-induced rewardc.f., , .
Our observed activation patterns in the brain suggest that female body configuration represents a salient stimulus to men and that optimal female body configurations activate areas of men's brains that are associated with reward processing and appetitive behaviors. This activation may represent the proximate neural mechanism of attraction to females that express curvaceous body types and also further account for cross-cultural findings showing that optimal WHR (∼.7) as being consistently rated as attractive. Lastly, this finding may extend our understanding of some men's proclivity to develop a preoccupation with stimuli depicting optimally designed women (e.g., pornography), . Interestingly, our findings did not demonstrate that BMI had a large effect on brain activation except in areas associated with simple visual evaluations of shape and size. This does not downplay the importance of BMI in evaluations of female attractiveness, but may suggest that BMI's role in these evaluations is less the product of evolved psychological mechanisms and more the part of culturally driven, or societal based norms and perceptions.
The authors would like to thank Magdalena Babiszewska for her assistance with data collection. The authors would also like to thank Rebecca Burch, J. Mark Davis, Jennifer Davis, Andrew Gallup, Gordon Gallup, Aaron Goetz, Austen Krill, Katherine Reding, Todd Shackelford, Kyrre Wahtne and the staff at MARIARC for comments on an earlier draft and assistance with fMRI data acquisition.
Conceived and designed the experiments: SMP DS. Performed the experiments: SMP. Analyzed the data: SMP. Wrote the paper: SMP DS. Contributed stimuli for experiments: DS.
- 1. Hughes SM, Gallup GGJ (2003) Sex differences in morphological predictors of sexual behavior: Shoulder to hip and waist to hip ratios. Evolution and Human Behavior 24: 173–178.SM HughesGGJ Gallup2003Sex differences in morphological predictors of sexual behavior: Shoulder to hip and waist to hip ratios.Evolution and Human Behavior24173178
- 2. Gangestad SW, Cousins AJ (2001) Adaptive design, female mate preferneces and shifts across the menstrual cycle. Annual Review of Sex Research 12: 145–185.SW GangestadAJ Cousins2001Adaptive design, female mate preferneces and shifts across the menstrual cycle.Annual Review of Sex Research12145185
- 3. Gangestad SW, Garver-Apgar CE, Simpson JA, Cousins AJ (2007) Changes in women's mate choice preferences across the menstrual cycle. Journal of Personality and Social Psychology 92: 151–163.SW GangestadCE Garver-ApgarJA SimpsonAJ Cousins2007Changes in women's mate choice preferences across the menstrual cycle.Journal of Personality and Social Psychology92151163
- 4. Penton-Voak IS, Jones BC, Little AC, Baker S, Tiddeman B, et al. (2001) Symmetry, sexual dimorphism in facial proportions and male facial attractiveness. Proc Biol Sci 268: 1617–1623.IS Penton-VoakBC JonesAC LittleS. BakerB. Tiddeman2001Symmetry, sexual dimorphism in facial proportions and male facial attractiveness.Proc Biol Sci26816171623
- 5. Penton-Voak IS, Little AC, Jones BC, Burt DM, Tiddeman BP, et al. (2003) Female Condition Influences Preferences for Sexual Dimorphism in Faces of Male Humans (Homo sapiens). Journal of Comparative Psychology 117: 264–271.IS Penton-VoakAC LittleBC JonesDM BurtBP Tiddeman2003Female Condition Influences Preferences for Sexual Dimorphism in Faces of Male Humans (Homo sapiens).Journal of Comparative Psychology117264271
- 6. Penton-Voak IS, Perrett DI, Castles DL, Kobayashi T, Burt DM, et al. (1999) Menstrual cycle alters face preference. Nature 399: 741–742.IS Penton-VoakDI PerrettDL CastlesT. KobayashiDM Burt1999Menstrual cycle alters face preference.Nature399741742
- 7. Thornhill R, Gangestad SW (1999) Facial attractiveness. Trends Cogn Sci 3: 452–460.R. ThornhillSW Gangestad1999Facial attractiveness.Trends Cogn Sci3452460
- 8. Thornhill R, Grammer K (1999) The Body and Face of Woman: One Ornament that Signals Quality? Evolution and Human Behavior 20: 105–120.R. ThornhillK. Grammer1999The Body and Face of Woman: One Ornament that Signals Quality?Evolution and Human Behavior20105120
- 9. Aharon I, Etcoff N, Ariely D, Chabris CF, O'Connor E, et al. (2001) Beautiful faces have variable reward value: fMRI and behavioral evidence. Neuron 32: 537–551.I. AharonN. EtcoffD. ArielyCF ChabrisE. O'Connor2001Beautiful faces have variable reward value: fMRI and behavioral evidence.Neuron32537551
- 10. O'Doherty J, Winston J, Critchley H, Perrett D, Burt DM, et al. (2003) Beauty in a smile: the role of medial orbitofrontal cortex in facial attractiveness. Neuropsychologia 41: 147–155.J. O'DohertyJ. WinstonH. CritchleyD. PerrettDM Burt2003Beauty in a smile: the role of medial orbitofrontal cortex in facial attractiveness.Neuropsychologia41147155
- 11. Reding K, Platek SM(submitted) Reward responses to male faces flutuate across the menstrual cycle: An event related fMRI study. Evolution and Human Behavior. K. RedingSM Platek(submitted) Reward responses to male faces flutuate across the menstrual cycle: An event related fMRI study.Evolution and Human Behavior
- 12. Rupp HA, James TW, Ketterson ED, Sengelaub DR, Janssen E, et al. (2009) Neural activation in the orbitofrontal cortex in response to male faces increases during the follicular phase. Horm Behav 56: 66–72.HA RuppTW JamesED KettersonDR SengelaubE. Janssen2009Neural activation in the orbitofrontal cortex in response to male faces increases during the follicular phase.Horm Behav566672
- 13. Dufour DL, Slather ML (2002) Comparative and evolutionary dimensions of the energetics of human pregnancy and lactation. American Journal of Human Biology 14: 584–602.DL DufourML Slather2002Comparative and evolutionary dimensions of the energetics of human pregnancy and lactation.American Journal of Human Biology14584602
- 14. Singh D, Randall PK (2007) Beauty is in the eye of the plastic surgeon: Waist-hip ratio (WHR) and women's attractiveness. Personality and Individual Differences 43: 329–340.D. SinghPK Randall2007Beauty is in the eye of the plastic surgeon: Waist-hip ratio (WHR) and women's attractiveness.Personality and Individual Differences43329340
- 15. Singh D (1993) Adaptive significance of female physical attractiveness: role of waist-to-hip ratio. J Pers Soc Psychol 65: 293–307.D. Singh1993Adaptive significance of female physical attractiveness: role of waist-to-hip ratio.J Pers Soc Psychol65293307
- 16. Singh D (1994) Waist-to-hip ratio and judgment of attractiveness and healthiness of female figures by male and female physicians. Int J Obes Relat Metab Disord 18: 731–737.D. Singh1994Waist-to-hip ratio and judgment of attractiveness and healthiness of female figures by male and female physicians.Int J Obes Relat Metab Disord18731737
- 17. Wetsman A, Marlowe F (1999) How Universal Are Preferences for Female Waist-to-Hip Ratios? Evidence from the Hadza of Tanzania. Evolution and Human Behavior 20: 219–228.A. WetsmanF. Marlowe1999How Universal Are Preferences for Female Waist-to-Hip Ratios? Evidence from the Hadza of Tanzania.Evolution and Human Behavior20219228
- 18. Yu DW, Shepard GH (1998) Is beauty in the eye of the beholder? Nature 396: 321–322.DW YuGH Shepard1998Is beauty in the eye of the beholder?Nature396321322
- 19. Jasien G, Ziomkiewwicz A, Ellison PT, Lipson SF, Thune I (2004) Large breats and narrow waists indicate high reproductive potential in women. Proc Biol Sci 271: 1213–1217.G. JasienA. ZiomkiewwiczPT EllisonSF LipsonI. Thune2004Large breats and narrow waists indicate high reproductive potential in women.Proc Biol Sci27112131217
- 20. Zaadstra BM, Seidell JC, Van Noord PAH, Te Velde ER, Habbema JDF, et al. (1993) Fat and women fecundity: prospective study of body fat distribution in conception rates. British Medical Journal 306: 484–487.BM ZaadstraJC SeidellPAH Van NoordER Te VeldeJDF Habbema1993Fat and women fecundity: prospective study of body fat distribution in conception rates.British Medical Journal306484487
- 21. Lassek W, Gaulin SJC (2008) Wasit-to-hip ratio and cognitive ability: is gluteofemoral fat a priveleged store of neurodevelopmental resources? Evolution and Human Behavior 29: 28–36.W. LassekSJC Gaulin2008Wasit-to-hip ratio and cognitive ability: is gluteofemoral fat a priveleged store of neurodevelopmental resources?Evolution and Human Behavior292836
- 22. Nelson TL, Palmer RF, Pedersen NL, Miles TP (1999) Psychological and behavioral predictors of body fat distribution: age and gender effects. Obes Res 7: 199–207.TL NelsonRF PalmerNL PedersenTP Miles1999Psychological and behavioral predictors of body fat distribution: age and gender effects.Obes Res7199207
- 23. Swami V, Miller R, Furnham A, Penke L, TovÈe MJ (2008) The influence of men's sexual strategies on perceptions of women's bodily attractiveness, health and fertility. Personality and Individual Differences 44: 98–107.V. SwamiR. MillerA. FurnhamL. PenkeMJ TovÈe2008The influence of men's sexual strategies on perceptions of women's bodily attractiveness, health and fertility.Personality and Individual Differences4498107
- 24. Chen NK, Dickey CC, Yoo SS, Guttman CR, Panych LP (2003) Selection of voxel size and slice orientation for fMRI in the presence of susceptibility field graidents: application to imaging of the amygdala. NeuroImage 19: 817–825.NK ChenCC DickeySS YooCR GuttmanLP Panych2003Selection of voxel size and slice orientation for fMRI in the presence of susceptibility field graidents: application to imaging of the amygdala.NeuroImage19817825
- 25. Smith SM, Jenkinson M, Woolrich MW, Beckman CF, Behrens TEJ, et al. (2004) Advances in functional and structural MR image analysis and implementation as FSL. NeuroImage 23: 208–219.SM SmithM. JenkinsonMW WoolrichCF BeckmanTEJ Behrens2004Advances in functional and structural MR image analysis and implementation as FSL.NeuroImage23208219
- 26. Berns GS, McClure SM, Pagnoni G, Mantague PR (2001) Predictability modulates human brain response to reward. Journal of Neuroscience 21: 2793–2798.GS BernsSM McClureG. PagnoniPR Mantague2001Predictability modulates human brain response to reward.Journal of Neuroscience2127932798
- 27. Breiter HC, Rosen BR (1999) Functional magnetic resonance imaging of brain reward circuitry in the human. Ann N Y Acad Sci 877: 523–547.HC BreiterBR Rosen1999Functional magnetic resonance imaging of brain reward circuitry in the human.Ann N Y Acad Sci877523547
- 28. O'Doherty J, Kringelbach ML, Rolls ET, Hornack J, Andrews C (2001) Abstract reward and punishment representations in the human orbitalfrontal cortex. Nature Neuroscience 4: 95–102.J. O'DohertyML KringelbachET RollsJ. HornackC. Andrews2001Abstract reward and punishment representations in the human orbitalfrontal cortex.Nature Neuroscience495102
- 29. Platek SM, Krill AL, Wilson B (2009) mplicit trustworthiness ratings of self-resembling faces activate brain centers involved in reward. Neuropsychologia 47: 289–293.SM PlatekAL KrillB. Wilson2009mplicit trustworthiness ratings of self-resembling faces activate brain centers involved in reward.Neuropsychologia47289293
- 30. Engell AD, Haxby JV, Todorov A (2007) Implicit trustworthiness decisions: Automatic coding of face properties in the human amygdal. Journal of Cognitive Neuroscience 19: 1508–1519.AD EngellJV HaxbyA. Todorov2007Implicit trustworthiness decisions: Automatic coding of face properties in the human amygdal.Journal of Cognitive Neuroscience1915081519
- 31. Willis J, Todorov A (2006) First impressions: Making up your mind after a 100-ms exposure to a face. Psychological Science 17: 592–598.J. WillisA. Todorov2006First impressions: Making up your mind after a 100-ms exposure to a face.Psychological Science17592598
- 32. Platek SM, Keenan JP, Mohamed FB (2005) Sex differences in the neural correlates of child facial resemblance: an event related fMRI study. NeuroImage 25: 1336–1344.SM PlatekJP KeenanFB Mohamed2005Sex differences in the neural correlates of child facial resemblance: an event related fMRI study.NeuroImage2513361344
- 33. Platek SM, Kemp SM (2009) Is family special to the brain? An event-related fMRI study of familiar, familial, and self-face recognition. Neuropsychologia 47: 849–858.SM PlatekSM Kemp2009Is family special to the brain? An event-related fMRI study of familiar, familial, and self-face recognition.Neuropsychologia47849858
- 34. Critchley HD, Tang J, Glaser D, Butterworth B, Dolan RJ (2005) Anterior cingulate activity during error and autonomic response. NeuroImage 27: 885–895.HD CritchleyJ. TangD. GlaserB. ButterworthRJ Dolan2005Anterior cingulate activity during error and autonomic response.NeuroImage27885895
- 35. Hedges VL, Chakravarty S, Nestler EJ, Meisel RL (2009) Delta FosB overexpression in the nucleus accumbens enhances sexual reward in female Syrian hamsters. Genes Brain Behav 8: 442–449.VL HedgesS. ChakravartyEJ NestlerRL Meisel2009Delta FosB overexpression in the nucleus accumbens enhances sexual reward in female Syrian hamsters.Genes Brain Behav8442449
- 36. Hernandez L, Hoebel BG (1988) Food reward and cocaine increase extracellular dopamine in the nucleus accumbens as measured by microdialysis. Life Sci 42: 1705–1712.L. HernandezBG Hoebel1988Food reward and cocaine increase extracellular dopamine in the nucleus accumbens as measured by microdialysis.Life Sci4217051712
- 37. Hikosaka O (2007) Basal ganglia mechanisms of reward-oriented eye movement. Ann N Y Acad Sci 1104: 229–249.O. Hikosaka2007Basal ganglia mechanisms of reward-oriented eye movement.Ann N Y Acad Sci1104229249
- 38. Pizzagalli DA, Holmes AJ, Dillon DG, Goetz EL, Birk JL, et al. (2009) Reduced caudate and nucleus accumbens response to rewards in unmedicated individuals with major depressive disorder. Am J Psychiatry 166: 702–710.DA PizzagalliAJ HolmesDG DillonEL GoetzJL Birk2009Reduced caudate and nucleus accumbens response to rewards in unmedicated individuals with major depressive disorder.Am J Psychiatry166702710
- 39. Samejima K, Ueda Y, Doya K, Kimura M (2005) Representation of action-specific reward values in the striatum. Science 310: 1337–1340.K. SamejimaY. UedaK. DoyaM. Kimura2005Representation of action-specific reward values in the striatum.Science31013371340
- 40. Stoeckel LE, Kim J, Weller RE, Cox JE, Cook EW III, et al. (2009) Effective connectivity of a reward network in obese women. Brain Res Bull 79: 388–395.LE StoeckelJ. KimRE WellerJE CoxEW Cook III2009Effective connectivity of a reward network in obese women.Brain Res Bull79388395
- 41. Heinz A, Siessmeier T, Wrase J, Hermann D, Klein S, et al. (2004) Correlation between dopamine D(2) receptors in the ventral striatum and central processing of alcohol cues and craving. Am J Psychiatry 161: 1783–1789.A. HeinzT. SiessmeierJ. WraseD. HermannS. Klein2004Correlation between dopamine D(2) receptors in the ventral striatum and central processing of alcohol cues and craving.Am J Psychiatry16117831789
- 42. Bjork JM, Knutson B, Hommer DW (2008) Incentive-elicited striatal activation in adolescent children of alcoholics. Addiction 103: 1308–1319.JM BjorkB. KnutsonDW Hommer2008Incentive-elicited striatal activation in adolescent children of alcoholics.Addiction10313081319
- 43. He F, Guan H, Zhao Z, Miao X, Zhou Q, et al. (2008) Evaluation of short-term psychological functions in opiate addicts after ablating the nucleus accumbens via stereotactic surgery. Stereotact Funct Neurosurg 86: 320–329.F. HeH. GuanZ. ZhaoX. MiaoQ. Zhou2008Evaluation of short-term psychological functions in opiate addicts after ablating the nucleus accumbens via stereotactic surgery.Stereotact Funct Neurosurg86320329
- 44. Bostwick JM, Bucci JA (2008) Internet sex addiction treated with naltrexone. Mayo Clin Proc 83: 226–230.JM BostwickJA Bucci2008Internet sex addiction treated with naltrexone.Mayo Clin Proc83226230
- 45. Stein DJ, Black DW, Shapira NA, Spitzer RL (2001) Hypersexual disorder and preoccupation with internet pornography. Am J Psychiatry 158: 1590–1594.DJ SteinDW BlackNA ShapiraRL Spitzer2001Hypersexual disorder and preoccupation with internet pornography.Am J Psychiatry15815901594