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Young SN, Leyton M. The role of serotonin in human mood and social interaction. Insight from altered tryptophan levels. Pharmacol Biochem Behav 2002; 71:857-65. [PMID: 11888576 DOI: 10.1016/s0091-3057(01)00670-0] [Citation(s) in RCA: 230] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Alterations in brain tryptophan levels cause changes in brain serotonin synthesis, and this has been used to study the implication of altered serotonin levels in humans. In the acute tryptophan depletion (ATD) technique, subjects ingest a mixture of amino acids devoid of tryptophan. This results in a transient decline in tissue tryptophan and in brain serotonin. ATD can result in lower mood and increase in irritability or aggressive responding. The magnitude of the effect varies greatly depending on the susceptibility of the subject to lowered mood or aggressivity. Unlike ATD, tryptophan can be given chronically. Tryptophan is an antidepressant in mild to moderate depression and a small body of data suggests that it can also decrease aggression. Preliminary data indicate that tryptophan also increases dominant behavior during social interactions. Overall, studies manipulating tryptophan levels support the idea that low serotonin can predispose subjects to mood and impulse control disorders. Higher levels of serotonin may help to promote more constructive social interactions by decreasing aggression and increasing dominance.
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Affiliation(s)
- Simon N Young
- Department of Psychiatry, McGill University, 1033 Pine Avenue West, H3A 1A1, Montréal, Québec, Canada.
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102
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Vázquez DM, Eskandari R, Zimmer CA, Levine S, López JF. Brain 5-HT receptor system in the stressed infant rat: implications for vulnerability to substance abuse. Psychoneuroendocrinology 2002; 27:245-72. [PMID: 11750782 DOI: 10.1016/s0306-4530(01)00048-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Clinical and epidemiological studies have found an association between aversive experiences early in life and an increased risk for depression, anxiety and substance abuse. In order to elucidate the mechanisms by which adverse life events are translated into behavioral and psychological abnormalities, we used a rat model to study the impact of chronic injection and 24 h maternal deprivation on the developing rat brain. Specifically, we investigated the regulation of molecules related to the 5-HT (5-HT) system and studied the effect of desipramine administration on animals that were maternally deprived (DEP) on day 13 of life compared with non-deprived animals. We found that maternal deprivation caused an enhanced corticosterone response to an acute stress. Maternally deprived animals also showed a decrease in corticosteroid receptors and an increase in 5-HT 1A and 1B receptors restricted to the CA1 region of the hippocampus. Desipramine prevented the maternal deprivation induced up-regulation of the 5-HT 1B receptor and the enhanced adrenocortical response observed in these animals. Interestingly, non-deprived animals receiving chronic injections showed a decrease in hippocampal 5-HT1B receptor mRNA. At 80 days of age, a group of animals that were treated as infants were given the option of drinking from two identical water bottles, one bottle contained tap water, while the second contained ethanol at increasing concentrations. Animals that received chronic injections during the newborn period consumed more alcohol than those that were not injected. On the other hand, maternal deprivation did not have an impact on alcohol consumption. Alcohol preference has implications to the organism since studies of drug self-administration in laboratory animals have shown that ethanol ingestion is positively related to the use of other drugs, principally opioids and psychostimulants. Our findings suggest that the quality and/or chronicity of early life stressors can influence the neurobiological substrates that may trigger and/or predispose individuals to substance abuse in adulthood.
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MESH Headings
- Adrenal Cortex/physiology
- Alcohol Drinking/psychology
- Animals
- Antidepressive Agents, Tricyclic/therapeutic use
- Autoradiography
- Brain Chemistry/physiology
- Carrier Proteins/metabolism
- Chronic Disease
- Densitometry
- Desipramine/therapeutic use
- Female
- In Situ Hybridization
- Male
- Maternal Deprivation
- Membrane Glycoproteins/metabolism
- Membrane Transport Proteins
- Nerve Tissue Proteins/metabolism
- RNA Probes
- RNA, Messenger/biosynthesis
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT2A
- Receptors, Serotonin/biosynthesis
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/metabolism
- Receptors, Serotonin, 5-HT1
- Serotonin Plasma Membrane Transport Proteins
- Stress, Psychological/drug therapy
- Stress, Psychological/metabolism
- Substance-Related Disorders/metabolism
- Substance-Related Disorders/prevention & control
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Affiliation(s)
- Delia M Vázquez
- Department of Pediatrics, University of Michigan, Medical Science Research Building, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0646, USA.
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103
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Abstract
Phenytoin is a widely used anticonvulsant drug that also reduces aggressive behavior. Aggression in humans and animals is often associated with low serotonin levels. This study examined the anti-aggressive properties of phenytoin in rodent isolation-induced aggression using a resident-intruder test to quantify aggression. Chronic treatment with p-chlorophenyl-alanine (PCPA), a competitive inhibitor of serotonin synthesis, significantly enhanced resident attack behavior compared to saline-treated control rats. Phenytoin dose-dependently reduced aggressive behavior specifically in PCPA-treated rats, but had no anti-aggressive properties in saline-treated rats. These data suggest that aggressive behavior in this model may be related to neuronal hyperexcitability that is sensitive to the anticonvulsant effects of phenytoin. Further, these data suggest isolation-induced aggression in PCPA-treated rats may be a useful model to investigate aggression associated with low serotonin in the brain.
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Affiliation(s)
- N B Keele
- Department of Psychology and Neuroscience, Baylor University, Box 97334, Waco, TX 76798-7334, USA
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104
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Williams RB, Marchuk DA, Gadde KM, Barefoot JC, Grichnik K, Helms MJ, Kuhn CM, Lewis JG, Schanberg SM, Stafford-Smith M, Suarez EC, Clary GL, Svenson IK, Siegler IC. Central nervous system serotonin function and cardiovascular responses to stress. Psychosom Med 2001; 63:300-5. [PMID: 11292279 DOI: 10.1097/00006842-200103000-00016] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The objective of this study was to evaluate the impact of indices of central nervous system (CNS) serotonin function on cardiovascular reactivity to mental stress. METHODS Lumbar puncture was performed on 54 healthy volunteers to obtain cerebrospinal fluid (CSF) for determination of 5-hydroxyindoleacetic acid (5HIAA) levels. Genotypes were determined with respect to a functional polymorphism of the serotonin transporter gene promoter region (5HTTLPR). Subjects then underwent mental stress testing. RESULTS Persons with one or two long (l) 5HTTLPR alleles had CSF levels of the major serotonin metabolite, 5HIAA, that were 50% higher than those of persons with the s/s 5HTTLPR genotype. Persons with one or two l alleles or higher CSF 5HIAA levels also exhibited greater blood pressure and heart rate responses to a mental stress protocol. CONCLUSIONS These findings suggest the 5HTTLPR polymorphism affects CNS serotonin function, and they are consistent with the general hypothesis that CNS serotonin function is involved in the regulation of potentially health-damaging biobehavioral characteristics. In particular, the l allele could contribute, through its association with increased cardiovascular reactivity to stress, to increased risk of cardiovascular disease.
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Affiliation(s)
- R B Williams
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina 27710, USA.
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105
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Abstract
The hormones and other physiological agents that mediate the effects of stress on the body have protective and adaptive effects in the short run and yet can accelerate pathophysiology when they are over-produced or mismanaged. Here we consider the protective and damaging effects of these mediators as they relate to the immune system and brain. 'Stress' is a principle focus, but this term is rather imprecise. Therefore, the article begins by noting two new terms, allostasis and allostatic load that are intended to supplement and clarify the meanings of 'stress' and 'homeostasis'. For the immune system, acute stress enhances immune function whereas chronic stress suppresses it. These effects can be beneficial for some types of immune responses and deleterious for others. A key mechanism involves the stress-hormone dependent translocation of immune cells in the blood to tissues and organs where an immune defense is needed. For the brain, acute stress enhances the memory of events that are potentially threatening to the organism. Chronic stress, on the other hand, causes adaptive plasticity in the brain, in which local neurotransmitters as well as systemic hormones interact to produce structural as well as functional changes, involving the suppression of ongoing neurogenesis in the dentate gyrus and remodelling of dendrites in the Ammon's horn. Under extreme conditions only does permanent damage ensue. Adrenal steroids tell only part of the story as far as how the brain adapts, or shows damage, and local tissue modulators - cytokines for the immune response and excitatory amino acid neurotransmitters for the hippocampus. Moreover, comparison of the effects of experimenter-applied stressors and psychosocial stressors show that what animals do to each other is often more potent than what experimenters do to them. And yet, even then, the brain is resilient and capable of adaptive plasticity. Stress-induced structural changes in brain regions such as the hippocampus have clinical ramifications for disorders such as depression, post-traumatic stress disorder and individual differences in the aging process.
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Affiliation(s)
- B S McEwen
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Avenue, Box 165, 10021, New York, NY, USA.
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106
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Tiefenbacher S, Novak MA, Jorgensen MJ, Meyer JS. Physiological correlates of self-injurious behavior in captive, socially-reared rhesus monkeys. Psychoneuroendocrinology 2000; 25:799-817. [PMID: 10996475 DOI: 10.1016/s0306-4530(00)00027-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study examined the relationship between self-injurious behavior (SIB) in rhesus monkeys and several biological variables, including monoamine metabolites in cerebrospinal fluid (CSF) and circulating levels of ACTH, cortisol, and testosterone. Cisternal CSF and blood plasma samples were obtained from 23 individually housed male rhesus macaques, 14 of which had a veterinary record of self-inflicted wounding. CSF samples were analyzed for 5-hydroxyindole-3-acetic acid (5-HIAA), homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) using isocratic high-performance liquid chromatography with electrochemical detection (HPLC-EC). Plasma samples were analyzed for ACTH, cortisol, and testosterone using commercially available radioimmunoassays (RIAs). Rates of self-directed biting were determined by systematic observation of all monkeys. Monkeys with SIB did not differ from controls in their basal monoamine or gonadal activity. However, the SIB group showed consistently lower mean plasma cortisol levels than the control group. Plasma cortisol was negatively correlated with rates of self-directed biting. These results suggest a persistent dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in monkeys with SIB. It is not yet clear whether this phenomenon of low cortisol represents chronically reduced adrenocortical secretion under basal conditions or a difference in response to the mild stress of capture and chemical restraint. The implications of these findings will be discussed with respect to SIB in humans as well as post-traumatic stress disorder (PTSD), a condition characterized by pituitary-adrenocortical hypoactivity.
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Affiliation(s)
- S Tiefenbacher
- Neuroscience and Behavior Program, Department of Psychology, Tobin Hall, University of Massachusetts, Amherst, MA 01003-7710, USA
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107
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Abstract
BACKGROUND Community cohort studies and meta-analyses of randomized trials have shown a relation between low or lowered cholesterol and death by violence (homicide, suicide, accident); in primates, cholesterol reduction has been linked to increased behavioral acts of aggression (Kaplan J, Manuck S. The effects of fat and cholesterol on aggressive behaviour in monkeys. Psychosom. Med 1990;52:226-7; Kaplan J, Shively C, Fontenot D, Morgan T, Howell S, Manuck S et al. Demonstration of an association among dietary cholesterol, central serotonergic activity, and social behaviour in monkeys. Psychosom. Med 1994;56:479-84.). In this study we test for the first time whether cholesterol level is related to commission of violent crimes against others in a large community cohort. METHODS We merged one-time cholesterol measurements on 79,777 subjects enrolled in a health screening project in Varmland, Sweden with subsequent police records for arrests for violent crimes in men and women aged 24-70 at enrollment; and with information on covariates. We performed a nested case control comparison of cholesterol in violent criminals - defined as those with two or more crimes of violence against others - to cholesterol in nonoffenders matched on age, enrollment year, sex, education and alcohol, using variable-ratio matching, with a nonparametric sign test. RESULTS One hundred individuals met criteria for criminal violence. Low cholesterol (below the median) was strongly associated with criminal violence in unadjusted analysis (Men: risk ratio 1.94, P=0.002; all subjects risk ratio 2.32, P<0.001). Age emerged as a strong confounder. Adjusting for covariates using a matching procedure, violent criminals had significantly lower cholesterol than others identical in age, sex, alcohol indices and education, using a nonparametric sign test (P=0.012 all subjects; P=0.035 men). CONCLUSIONS Adjusting for other factors, low cholesterol is associated with increased subsequent criminal violence.
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Affiliation(s)
- B A Golomb
- Department of Medicine, University of California, Los Angeles, CA 92093-0995, USA.
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108
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DePetrillo PB, Bennett AJ, Speers D, Suomi SJ, Shoaf SE, Karimullah K, Dee Higley J. Ondansetron modulates pharmacodynamic effects of ketamine on electrocardiographic signals in rhesus monkeys. Eur J Pharmacol 2000; 391:113-9. [PMID: 10720642 DOI: 10.1016/s0014-2999(00)00056-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Electrocardiographic signal dynamics were examined in rhesus monkeys (Macaca mulatta) before and after treatment with ketamine and/or ondansetron. Ketamine exerts differential pharmacodynamic effects on behavior in animals stratified according to a measure of central serotonergic turnover. We hypothesized that measures of serotonergic turnover might explain some of the variance in the electrocardiographic (ECG) response to ketamine. Electrocardiographic recordings of animals were obtained at baseline, after administration of either saline or ondansetron (0.125 mg/kg), and after administration of ketamine (15 mg/kg). Electrocardiographic signal dynamics were measured using an algorithm that extracts the Hurst parameter (H) of the interbeat interval (IBI) time-series. H decreased after ketamine administration, (mean+/-S.E.M.), 0.33+/-0.04 vs. 0.12+/-0.02, P</=0. 001, n=10. Cerebrospinal fluid 5-hydroxyindole-3-acetic acid (5-HIAA) concentrations, a measure of serotonergic turnover, predicted the monkeys' response to ketamine, H=0.001 (5-HIAA, pmol/ml)-0.130, R=0.66, P</=0.003, n=18. Ondansetron attenuated the response to ketamine, 0.14+/-0.02 vs. 0.08+/-0.02, P</=0.05, n=8, ondansetron vs. saline. These data provide evidence that naturally occurring differences in serotonin function alter the ECG response of the animals to ketamine and that activation of the serotonin type-3 receptor by ketamine is involved.
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Affiliation(s)
- P B DePetrillo
- Laboratory of Clinical Studies, Unit of Clinical and Biochemical Pharmacology, Division of Intramural Clinical and Biochemical Research, National Institutes of Health, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892-1256, USA
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109
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Evolutionary and ecological aspects of early brain malnutrition in humans. HUMAN NATURE-AN INTERDISCIPLINARY BIOSOCIAL PERSPECTIVE 2000; 11:1-26. [DOI: 10.1007/s12110-000-1000-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/1998] [Accepted: 05/24/1999] [Indexed: 10/23/2022]
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110
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Goldney RD. The Privilege and Responsibility of Suicide Prevention*Presidential Address, presented at the 20th Congress of the International Association for Suicide Prevention, Athens, Greece, 6-10 November 1999. CRISIS 2000. [DOI: 10.1027//0227-5910.21.1.8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Each year about a million people worldwide take their lives, and a further unknown number, but probably no less than 20 million, attempt suicide. In addition, for every person who engages in suicidal behavior, another five or six will be associated with them in some way, making a conservative total of 100 million people worldwide who are affected each year—and to whom we have some degree of responsibility. There is no one approach to suicide prevention, and probably more so than for any other human condition, we are privileged to be able to collaborate with many different disciplines in our endeavors. However, there is a considerable responsibility to ensure that whatever our own area of expertise and interest may be, we should apply universal principals of objective analysis to these diverse contributions. This is addressed by examining research from four broad areas. First, there are studies that irrevocably bring together the sociological and biological approaches to suicide. Second, there are reports that support the notion of the universality of suicide. Third, despite considerable attention paid to the media, its influence on suicide is very limited. And finally, although there have been pessimistic reviews, there are persuasive data from innovative research designs that have documented that we can prevent suicide.
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111
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Turecki G. O suicídio e sua relação com o comportamento impulsivo-agressivo. BRAZILIAN JOURNAL OF PSYCHIATRY 1999. [DOI: 10.1590/s1516-44461999000600006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
O suicídio é um sério problema de saúde pública, principalmente em países desenvolvidos, onde as altas taxas de suicídio entre jovens adultos do sexo masculino fazem com que este seja uma das principais causas de morte e de anos potenciais de vida perdidos. A etiologia do suicídio é certamente complexa, com diversos fatores contribuindo para a predisposição a este evento. Entre estes se encontram os fatores genéticos. Nos últimos anos, diversos estudos genético-epidemiológicos têm consistentemente sugerido que o componente genético é significativo. Entretanto, o modo exato através do qual os genes aumentam a predisposição de certos indivíduos a cometer o suicídio é ainda desconhecido. Há evidência crescente de que os fatores genéticos devem influenciar a predisposição ao suicídio via uma modulação dos comportamentos impulsivo e impulsivo-agressivo. Este artigo revisa e discute os estudos que investigaram fatores genéticos no comportamento suicida, assim como esta relação com os traços impulsivo-agressivos.
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112
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Lindell SG, Suomi SJ, Shoaf S, Linnoila M, Higley JD. Salivary prolactin as a marker for central serotonin turnover. Biol Psychiatry 1999; 46:568-72. [PMID: 10459408 DOI: 10.1016/s0006-3223(99)00037-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Central nervous system (CNS) serotonin deficits have been linked to many pathological behaviors in both human and nonhuman primates. The plasma prolactin response to fenfluramine has been widely used to assess CNS serotonin functioning in humans. Prolactin is also found as an integrated measure in saliva. We hypothesized that salivary prolactin concentrations would correlate positively with cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) in rhesus monkeys. Twenty-seven adult male and female rhesus macaques (Macaca mulatta) were sampled for concurrent saliva, blood, and CSF. Saliva and blood serum were assayed for prolactin concentrations, and CSF was assayed for 5-HIAA, homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG). Salivary prolactin concentrations were positively correlated with CSF 5-HIAA concentrations. No other relationships between any of the measures, including that between salivary prolactin and serum prolactin, were found to be statistically significant. These findings suggest the possibility of using salivary prolactin concentrations as an index of CNS serotonin turnover in humans.
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Affiliation(s)
- S G Lindell
- Laboratory of Comparative Ethology, National Institute on Child Health and Human Development, Poolesville, Maryland 20837-0529, USA
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113
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Leckman JF, Mayes LC. Preoccupations and behaviors associated with romantic and parental love. Perspectives on the origin of obsessive-compulsive disorder. Child Adolesc Psychiatr Clin N Am 1999. [PMID: 10442234 DOI: 10.1016/s1056-4993(18)30172-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This article first examines the hypothesis that the early phases of romantic love and early parental love share phenomenologically an overlapping set of mental states and behaviors. Second, the authors consider what is known of the neurobiologic substrates of these behaviors. Third, the authors evaluate the hypothesis that these highly conserved behavioral and neural systems and the genetic messages that guide their development are intimately involved in the pathogenesis of OCD.
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