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Differential EEG activation and pathological gambling
1232
alOL PSVCmATRV 1985;20:1232-1234
BRIEF R E P O R T S
Differential EEG Activation and Pathological Gambling Leonide Goldstein, Paul Manowitz, Rena Nora, Marshall Swartzburg, and Peter L. Carlton
Introduction Conservative estimates indicate that there are at least 1.1 million gamblers in the United States who meet the DSM-III criteria for pathological gambling. These estimates have provided an impetus to elucidate the factors that may contribute to this behavior (Lesieur and Custer 1984). Although psychosocial factors are undoubtedly of major etiological significance, there is also the possibility that a biologically based predisposition interacts with such factors in the development of pathological gambling. The credibility of this view would be substantially enhanced if it could be shown that some index of brain function discriminates between pathological gamblers and controls. On the theory that hemispheric dysregulation related to impulse control may be implicated, that prospect was examined by evaluating the electroencephalographic (EEG) signs of differential hemispheric activation induced by different task requirements. In particular, we studied the effects of verbal tasks chosen to differentially activate the left (L)
From the Deparanent of Psychiatry, University of Medicine and Dentistry of New Jersey-Rutgers Medical School (L.G., P.M., R.N., M.S., P.L.C.), Piscataway, and the Psychiatry Service, Veterans Administration Medical Center (R.N.), Lyons, N.J. Supported in part by a grant from the New Jersey Lottery Commission. Address reprint requests to Dr. Peter L. Carlton, Project Director, Department of Psychiatry, University of Medicine and Dentistry of New Jersey-Rutgers Medical School, Piscataway, NJ 08854. Received March 20, 1985; revised May 24, 1985.
© 1985 Society of Biological Psychiatry
hemisphere, as well as spatial tasks chosen to differentially activate the right (R).
Methods Eight healthy men (mean age 50.2 years), each with a documented history of pathological gambling, were recruited through local self-help groups; none were currently involved in gambling of any kind. In addition, 8 men (mean age 44.6 years), approximately matched to the gamblers with respect to education, occupation, and income, served as controls. All subjects were right-handed and none were taking medication. These subjects participated in two pairs of tasks, each of which required about 3 min. In one pair, the subject's eyes were closed (ECL), and he was instructed to imagine either a scene (R-activation) or giving a speech or explaining a procedure (L-activation). In the second pair of tasks, the subject's eyes were open (EOP), and he was asked to sort nonsense shapes into groups (R-activation) or to spell simple words by arranging letters in a tray (L-activation). The order of tasks was counterbalanced across subjects, and each pair of tasks was preceded by a 3-min rest period, during which the eyes were closed or open as determined by the condition in the tasks that followed. EEG signals were recorded at T3-T4 referenced to Cz, across frequencies from 1.3 to 30 Hz, and were quantified by analog integration. Computer analysis of these signals provided the 0006-3223/85/$03.30
Brief Reports
BIOLPSYCHIATRY
1233
1985;20:1232-1234
Table 1. Mean R/L Values and Indices of Task Differentiation Controls
Pathological gamblers
R/L ratios Condition EOP ECL
R/L ratios
Verbal
Nonverbal
Task differentiation
1.05 1.12
0.90 1.03
0.15 a 0.09 a
Verbal
Nonverbal
1.04 1.10
0.98 1.16
Task differentiation 0.06 a'b - 0.06"
°Differs from 0 (p ~< 0.02; based on two-tailed Mann-Whitney U tests). bDiffers from corresponding control value (p <~ 0.04). cDiffers from corresponding control value (p <~ 0.01).
ratios of R/L cumulated amplitudes for each 5sec epoch. These ratios were averaged over the artifact-free epochs constituting each task and then corrected for corresponding rest period differences (Benjamin 1963).
Results Because lower relative amplitudes reflect greater hemispheric activation, R/L ratios above 1.0 denote differential L-hemispheric activation, whereas ratios below 1.0 indicate differential Ractivation. (The analytic utility of this index has been discussed elsewhere; see Goldstein 1983; Von Knorring et al. 1983.) Differentiation appropriate to task requirement is indicated by higher ratios in verbal tasks as compared to relatively lower ratios in nonverbal tasks; thus, appropriate task differentiation is indicated by verbalnonverbal differences greater than zero. The values in Table 1 include the R/L ratios for both groups in all conditions; it also includes the more pertinent verbal-nonverbal differences that indicate task differentiation. As these differences show, both controls and gamblers appropriately differentiated tasks during the EOP condition (values of 0.15 and 0.06); the extent of task differentiation was, however, reliably greater in controls than gamblers. During the ECL tasks, controls were again characterized by reliable task differentiation (a difference of 0.09), whereas gamblers showed a reversal of differentiation (i.e., greater left hemisphere activation during the nonverbal task; task differentiation = - 0 . 0 6 ) . Thus, gamblers were again characterized by reliably lower levels of appropriate hemispheric differentiation.
Discussion Pathological gamblers, like other diagnostically categorized groups, are surely not homogeneous with respect to all pertinent factors. The data at hand suggest, however, that a highly selected subset from this population may be characterized by a deficit in task-appropriate hemispheric differentiation. This deficit is of particular interest because it parallels that observed by McGee and Goldstein (see Goldstein and Wiet 1979) in preliminary studies of unmedicated children diagnosed as having attention deficit disorder (ADD). Thus, although such a conclusion must now be a very tentative one, there is an indication that adult pathological gambling may share a common predispositional factor with alcoholism (Tarter et al. 1977; Wood et al. 1983); that is, both pathological gambling and alcoholism may be related to dysfunctional attention mechanisms and, more to the point, to the deficits in impulse control that characterize ADD. The expert technical assistance of Ms. Denise Lantz is gratefully acknowledged.
References Benjamin LS (1963): Statistical treatment of the law of initial values (LIV) in autonomic research: A review and recommendation. Psychosom Med 25:556-566. Goldstein L (1983): Some EEG correlates of behavioral states and traits in humans. Res Commun Psychol Psychiatr Behav 8:115-141.
1234
BIOLPSYCHIATRY
Brief Reports
1985 ;20:1232-1234
Goldstein L, and Wiet S (1979): Some quantitated hemispheric EEG correlates of psychopathology. Paper presented at Symposium of the International Convention of Psychologists. Lesieur HR, and Custer RL (1984): Pathological gambling: Roots, phases, and treatment. Ann Am Acad Pol Soc Sci 474:146--156. Tarter RE, McBride H, Buonpane N, and Schneider DU (1977): Differentiation of alcoholics: Childhood history of minimal brain dysfunction, family history and drinking pattern. Arch Gen Psychiatry 34:761-768.
Von Knotting L, Perris C, Goldstein L, Kewali D, Monakhov K, Vacca L (1983): Intercorrelations between different computer-based measures of the EEG alpha amplitude and its variability over time and their validity in differentiating healthy volunteers from depressed patients. Adv Biol Psychiatry 13:172-181. Wood D, Wender PH, Reimherr FW (1983): The prevalence of attention deficit disorder, residual type, or minimal brain dysfunction, in a population of male alcoholic patients. Am J Psychiatry 140:95-98.
Platelet 3H-Imipramine Binding in Depressed Elderly Patients Lon S. Schneider, James A. Severson, and R. Bruce Sloane
Introduction Recently, attention has been directed to platelet 3H-imipramine binding density as a marker of depressive illness. Several reports suggest that the maximal density of platelet imipramine binding sites (Bm~) is decreased in unmedicated subjects with unipolar or bipolar affective disorder when compared with control groups (Briley et al. 1980; Asarch et al. 1981; Paul et al. 1981; Raisman et al. 1981,) or with subjects with schizophrenia and schizoaffective disorder (Suranyi-Cadotte et al. 1983). The decrease in the Bma~of the depressives reported ranges from about 20% to 54% of the control groups'.
From the Department of Psychiatry and the Behavioral Sciences, University of Southern California School of Medicine, Los Angeles, CA. Address reprint requests to: Dr. Lon S. Schneider, University of Southern California School of Medicine, 1934 Hospital Place, Los Angeles, CA 90033. Received April 15, 1985; revised May 20, 1985.
More recently, there have been reports suggesting that there is no difference, or a slight increase, in 3H-imipramine binding between bipolar patients and controls (Berrettini et al., 1982; Mellerup et al. 1982). To date, comparisons of 3H-imipramine binding in depression have examined patients with mean ages less than 51 years. To our knowledge, no comparison of platelet 3H-imipramine binding has been made in depressed geriatric patients. Thus, there is presently no data available to suggest that 3H-imipramine binding is a viable biological marker for depression in the elderly. Additionally, the density of platelet binding sites for 3H-imipramine may decline with age (Langer et al. 1980). This might suggest an age-dependent variation in this putative biological marker that could affect interpretation of platelet 3H-imipramine binding data in the absence of appropriate controls. We report such a comparison.
alOL PSVCmATRV 1985;20:1232-1234
BRIEF R E P O R T S
Differential EEG Activation and Pathological Gambling Leonide Goldstein, Paul Manowitz, Rena Nora, Marshall Swartzburg, and Peter L. Carlton
Introduction Conservative estimates indicate that there are at least 1.1 million gamblers in the United States who meet the DSM-III criteria for pathological gambling. These estimates have provided an impetus to elucidate the factors that may contribute to this behavior (Lesieur and Custer 1984). Although psychosocial factors are undoubtedly of major etiological significance, there is also the possibility that a biologically based predisposition interacts with such factors in the development of pathological gambling. The credibility of this view would be substantially enhanced if it could be shown that some index of brain function discriminates between pathological gamblers and controls. On the theory that hemispheric dysregulation related to impulse control may be implicated, that prospect was examined by evaluating the electroencephalographic (EEG) signs of differential hemispheric activation induced by different task requirements. In particular, we studied the effects of verbal tasks chosen to differentially activate the left (L)
From the Deparanent of Psychiatry, University of Medicine and Dentistry of New Jersey-Rutgers Medical School (L.G., P.M., R.N., M.S., P.L.C.), Piscataway, and the Psychiatry Service, Veterans Administration Medical Center (R.N.), Lyons, N.J. Supported in part by a grant from the New Jersey Lottery Commission. Address reprint requests to Dr. Peter L. Carlton, Project Director, Department of Psychiatry, University of Medicine and Dentistry of New Jersey-Rutgers Medical School, Piscataway, NJ 08854. Received March 20, 1985; revised May 24, 1985.
© 1985 Society of Biological Psychiatry
hemisphere, as well as spatial tasks chosen to differentially activate the right (R).
Methods Eight healthy men (mean age 50.2 years), each with a documented history of pathological gambling, were recruited through local self-help groups; none were currently involved in gambling of any kind. In addition, 8 men (mean age 44.6 years), approximately matched to the gamblers with respect to education, occupation, and income, served as controls. All subjects were right-handed and none were taking medication. These subjects participated in two pairs of tasks, each of which required about 3 min. In one pair, the subject's eyes were closed (ECL), and he was instructed to imagine either a scene (R-activation) or giving a speech or explaining a procedure (L-activation). In the second pair of tasks, the subject's eyes were open (EOP), and he was asked to sort nonsense shapes into groups (R-activation) or to spell simple words by arranging letters in a tray (L-activation). The order of tasks was counterbalanced across subjects, and each pair of tasks was preceded by a 3-min rest period, during which the eyes were closed or open as determined by the condition in the tasks that followed. EEG signals were recorded at T3-T4 referenced to Cz, across frequencies from 1.3 to 30 Hz, and were quantified by analog integration. Computer analysis of these signals provided the 0006-3223/85/$03.30
Brief Reports
BIOLPSYCHIATRY
1233
1985;20:1232-1234
Table 1. Mean R/L Values and Indices of Task Differentiation Controls
Pathological gamblers
R/L ratios Condition EOP ECL
R/L ratios
Verbal
Nonverbal
Task differentiation
1.05 1.12
0.90 1.03
0.15 a 0.09 a
Verbal
Nonverbal
1.04 1.10
0.98 1.16
Task differentiation 0.06 a'b - 0.06"
°Differs from 0 (p ~< 0.02; based on two-tailed Mann-Whitney U tests). bDiffers from corresponding control value (p <~ 0.04). cDiffers from corresponding control value (p <~ 0.01).
ratios of R/L cumulated amplitudes for each 5sec epoch. These ratios were averaged over the artifact-free epochs constituting each task and then corrected for corresponding rest period differences (Benjamin 1963).
Results Because lower relative amplitudes reflect greater hemispheric activation, R/L ratios above 1.0 denote differential L-hemispheric activation, whereas ratios below 1.0 indicate differential Ractivation. (The analytic utility of this index has been discussed elsewhere; see Goldstein 1983; Von Knorring et al. 1983.) Differentiation appropriate to task requirement is indicated by higher ratios in verbal tasks as compared to relatively lower ratios in nonverbal tasks; thus, appropriate task differentiation is indicated by verbalnonverbal differences greater than zero. The values in Table 1 include the R/L ratios for both groups in all conditions; it also includes the more pertinent verbal-nonverbal differences that indicate task differentiation. As these differences show, both controls and gamblers appropriately differentiated tasks during the EOP condition (values of 0.15 and 0.06); the extent of task differentiation was, however, reliably greater in controls than gamblers. During the ECL tasks, controls were again characterized by reliable task differentiation (a difference of 0.09), whereas gamblers showed a reversal of differentiation (i.e., greater left hemisphere activation during the nonverbal task; task differentiation = - 0 . 0 6 ) . Thus, gamblers were again characterized by reliably lower levels of appropriate hemispheric differentiation.
Discussion Pathological gamblers, like other diagnostically categorized groups, are surely not homogeneous with respect to all pertinent factors. The data at hand suggest, however, that a highly selected subset from this population may be characterized by a deficit in task-appropriate hemispheric differentiation. This deficit is of particular interest because it parallels that observed by McGee and Goldstein (see Goldstein and Wiet 1979) in preliminary studies of unmedicated children diagnosed as having attention deficit disorder (ADD). Thus, although such a conclusion must now be a very tentative one, there is an indication that adult pathological gambling may share a common predispositional factor with alcoholism (Tarter et al. 1977; Wood et al. 1983); that is, both pathological gambling and alcoholism may be related to dysfunctional attention mechanisms and, more to the point, to the deficits in impulse control that characterize ADD. The expert technical assistance of Ms. Denise Lantz is gratefully acknowledged.
References Benjamin LS (1963): Statistical treatment of the law of initial values (LIV) in autonomic research: A review and recommendation. Psychosom Med 25:556-566. Goldstein L (1983): Some EEG correlates of behavioral states and traits in humans. Res Commun Psychol Psychiatr Behav 8:115-141.
1234
BIOLPSYCHIATRY
Brief Reports
1985 ;20:1232-1234
Goldstein L, and Wiet S (1979): Some quantitated hemispheric EEG correlates of psychopathology. Paper presented at Symposium of the International Convention of Psychologists. Lesieur HR, and Custer RL (1984): Pathological gambling: Roots, phases, and treatment. Ann Am Acad Pol Soc Sci 474:146--156. Tarter RE, McBride H, Buonpane N, and Schneider DU (1977): Differentiation of alcoholics: Childhood history of minimal brain dysfunction, family history and drinking pattern. Arch Gen Psychiatry 34:761-768.
Von Knotting L, Perris C, Goldstein L, Kewali D, Monakhov K, Vacca L (1983): Intercorrelations between different computer-based measures of the EEG alpha amplitude and its variability over time and their validity in differentiating healthy volunteers from depressed patients. Adv Biol Psychiatry 13:172-181. Wood D, Wender PH, Reimherr FW (1983): The prevalence of attention deficit disorder, residual type, or minimal brain dysfunction, in a population of male alcoholic patients. Am J Psychiatry 140:95-98.
Platelet 3H-Imipramine Binding in Depressed Elderly Patients Lon S. Schneider, James A. Severson, and R. Bruce Sloane
Introduction Recently, attention has been directed to platelet 3H-imipramine binding density as a marker of depressive illness. Several reports suggest that the maximal density of platelet imipramine binding sites (Bm~) is decreased in unmedicated subjects with unipolar or bipolar affective disorder when compared with control groups (Briley et al. 1980; Asarch et al. 1981; Paul et al. 1981; Raisman et al. 1981,) or with subjects with schizophrenia and schizoaffective disorder (Suranyi-Cadotte et al. 1983). The decrease in the Bma~of the depressives reported ranges from about 20% to 54% of the control groups'.
From the Department of Psychiatry and the Behavioral Sciences, University of Southern California School of Medicine, Los Angeles, CA. Address reprint requests to: Dr. Lon S. Schneider, University of Southern California School of Medicine, 1934 Hospital Place, Los Angeles, CA 90033. Received April 15, 1985; revised May 20, 1985.
More recently, there have been reports suggesting that there is no difference, or a slight increase, in 3H-imipramine binding between bipolar patients and controls (Berrettini et al., 1982; Mellerup et al. 1982). To date, comparisons of 3H-imipramine binding in depression have examined patients with mean ages less than 51 years. To our knowledge, no comparison of platelet 3H-imipramine binding has been made in depressed geriatric patients. Thus, there is presently no data available to suggest that 3H-imipramine binding is a viable biological marker for depression in the elderly. Additionally, the density of platelet binding sites for 3H-imipramine may decline with age (Langer et al. 1980). This might suggest an age-dependent variation in this putative biological marker that could affect interpretation of platelet 3H-imipramine binding data in the absence of appropriate controls. We report such a comparison.