Computer and video game addiction—a comparison between game users and non game users

Second objective is to describe a brain imaging study measuring dopamine release during computer game playing.. Nine abstinent “ecstasy” users and 8 control subjects were scanned at base

ISSN: 0095-2990 print / 1097-9891 online

DOI: 10.3109/00952990.2010.491879

Computer and Video Game Addiction—A Comparison

between Game Users and Non-Game Users

Aviv Malkiel Weinstein, Ph.D.

Department of Medical Biophysics and Nuclear Medicine, Hadassah Hospital, Ein Kerem, Jerusalem,

Israel, and Department of Nuclear Medicine, Sourasky Medical Center, Tel Aviv, Israel

Background: Computer game addiction is excessive or

com-pulsive use of computer and video games that may interfere with

daily life It is not clear whether video game playing meets

di-agnostic criteria for Didi-agnostic and Statistical Manual of Mental

Disorders, Fourth Edition (DSM-IV) Objectives: First objective is

to review the literature on computer and video game addiction

over the topics of diagnosis, phenomenology, epidemiology, and

treatment Second objective is to describe a brain imaging study

measuring dopamine release during computer game playing

Meth-ods: Article search of 15 published articles between 2000 and 2009

in Medline and PubMed on computer and video game addiction.

Nine abstinent “ecstasy” users and 8 control subjects were scanned

at baseline and after performing on a motorbike riding computer

game while imaging dopamine release in vivo with [123I] IBZM and

single photon emission computed tomography (SPECT) Results:

Psycho-physiological mechanisms underlying computer game

ad-diction are mainly stress coping mechanisms, emotional reactions,

sensitization, and reward Computer game playing may lead to

long-term changes in the reward circuitry that resemble the effects

of substance dependence The brain imaging study showed that

healthy control subjects had reduced dopamine D2 receptor

occu-pancy of 10.5% in the caudate after playing a motorbike riding

computer game compared with baseline levels of binding

consis-tent with increased release and binding to its receptors Ex-chronic

“ecstasy” users showed no change in levels of dopamine D2

recep-tor occupancy after playing this game Conclusion: This evidence

supports the notion that psycho-stimulant users have decreased

sensitivity to natural reward Significance: Computer game

ad-dicts or gamblers may show reduced dopamine response to stimuli

associated with their addiction presumably due to sensitization.

Keywords addictionx, brain imaging, computer game playing,

dopamine, reward, video game playing

INTRODUCTION

Problem Definition

Computer or video game addiction is excessive or compulsive

use of computer and video games that interferes with daily life

Address correspondence to Aviv M Weinstein,, Ph.D., Department

of Medical Biophysics and Nuclear Medicine, Hadassah Hospital, Ein

Kerem, Jerusalem, Israel E-mail: avivweinstein@yahoo.com

Users may play compulsively, isolating themselves from other forms of social contact, and focus almost entirely on in-game achievements rather than broader life events

Griffiths (1) has operationally defined addictive behavior as any behavior that features what he believes are the six core components of addiction (i.e., salience, mood modification, tol-erance, withdrawal symptoms, conflict, and relapse) He further argued that video game addiction fulfils the criterion of addic-tion by virtue of meeting these criteria In his view, since many video game users are excessive users and not addicts, video game addiction may be a medium for satisfaction of arousal and reward (see section on mechanisms of reward) In addition

to the neurochemical basis for addiction, there are accompa-nied behavioral markers of dependence in adolescents such as stealing, truancy, not doing homework, irritability if unable to play, etc Finally, single case studies have shown the video game addiction was used in order to compensate for deficiencies in one’s life in areas such as interpersonal relationships, physical appearance, disability, coping, etc Griffith (2) argued that al-though there are educational, social, and therapeutic benefits to video games play, taken in excess they could lead to addiction, playing 24 hours a day 7 days a week and in some cases to a gambling problem Finally, Griffiths (3) concluded that adverse effects of video game addiction are relatively minor and tempo-rary resolving spontaneously with decreased frequency of play

or to affect a small group of players

There is no evidence for genetic factors influencing video

or computer game addiction Most studies describe a behavior that is independent of other psychiatric disorders (e.g., not just secondary to another condition such as attention deficit hyper-activity disorder [ADHD] or mania) There is a single study suggesting co-morbidity with depression (4) and for comorbid-ity with ADHD (5) but there is no evidence for co-morbidcomorbid-ity with substance use disorder On the spectrum of impulsivity and obsessive-compulsive behavior, there is some evidence for impulsivity on the Barrat Impulsiveness scale (4), and exces-sive computer and video game playing supports the notion of obsessive-compulsive behavior although formal assessment of obsessive-compulsive behavior in these individuals has not been 268

done According to Griffiths (6) case studies of individuals who

use the Internet excessively may also provide better evidence of

whether Internet addiction exists, because the data collected are

much more detailed than data from surveys Case studies can

highlight the role of context in distinguishing excessive

gam-ing from addictive gamgam-ing and can demonstrate that excessive

gaming does not necessarily mean that a person is addicted It

is argued that online gaming addiction should be characterized

by the extent to which excessive gaming impacts negatively on

other areas of the gamers’ lives rather than the amount of time

spent playing It is also suggested that an activity cannot be

described as an addiction if there are few (or no) negative

con-sequences in the player’s life even if the gamer is playing 14

hours a day (7)

Currently, it is not clear whether video game playing meets

criteria for a syndrome, e.g., Diagnostic and Statistical

Man-ual of Mental Disorders, Fourth Edition (DSM-IV) or

ICD-10 definition of a clinically significant pattern (consistent

co-occurrence and time course) of behavioral and psychological

signs and symptoms that cause distress or impairment In 2007,

the American Psychiatric Association reviewed whether or not

video game addiction should be added to the new DSM to be

released in 2012 The conclusion was that there was not enough

evidence to warrant the inclusion of computer game addiction

as a disorder

DIAGNOSIS AND PREVALENCE

The diagnostic assessment of internet or computer game

dependency remains problematic Different studies in

differ-ent countries have used differdiffer-ent scales to assess prevalence

of computer game addiction A national Harris Poll survey of

1,178 U.S youths ages 8–18 years found that 8.5% of computer

gamers were pathological players according to standards

es-tablished for pathological gambling (Harris Interactive, 2007)

Among 323 German children ranging in age from 11 to 14

years, 9.3% (N= 30) met criteria for dependency and

patholog-ical gaming using DSM-IV and ICD-10 criteria (8) A second

study of 7069 computer-game players reported that 11.9% met

three of the diagnostic criteria for addiction (9) Finally, among

221 computer game players, 6.3% have met ICD-10 criterion of

addiction (10) Among 2327 Norwegian youth, 2.7% (4.2% of

the boys, 1.1% of the girls) fulfilled the criteria for pathological

playing following a “Diagnostic Questionnaire for Internet

Ad-diction of Young;” 9.8% (14.5% of the boys, 5% of the girls)

were considered to be engaging in “at risk playing” (11) In the

United Kingdom, a survey of 387 adolescents (12–16 years of

age) found that 20% met computer dependence using a scale

adapted from the DSM-III-R criteria for pathological gambling

(12) A German National survey of 7000 gamers found that

12% met three of the criterion for internet addiction (9)

Re-sults of a German nationwide survey of 44,610 male and female

ninth-graders in 2007 and 2008 have shown that 3% of the male

and.3% of the female students were diagnosed as dependent on

video games Video game dependency (VGD) was accompa-nied by increased levels of psychological and social stress in the form of lower school achievement, increased truancy, reduced sleep time, limited leisure activities, and increased thoughts of committing suicide In addition, it becomes evident that per-sonal risk factors were crucial for VGD (13) Finally, a survey

of 3,975 Turkish undergraduate students found that the most preferred type of game was violent games; while preference for strategy and fantasy role-play games has increased with age, preference for other games has decreased (14)

This review searched articles published between 2000 and

2009 in Medline and PubMed using the key word computer and video game addiction over the topics of diagnosis, phenomenol-ogy, epidemiolphenomenol-ogy, and treatment

WHY DO PEOPLE BECOME ADDICTED TO COMPUTER GAME PLAYING?

Although repetition of favorite activities has a moderate ef-fect upon computer game addiction, flow experience, the emo-tional state embracing percepemo-tional distortion and enjoyment shows a strong impact on addiction in Taiwanese players (15) Responses of computer game players in Taiwan have qualita-tively reflected their psychological needs and motivations in daily life, but also to the interplay of real self and virtual self, compensatory, or extensive satisfaction for their needs and self-reflections (16) Social relationships and the specific time and flexibility characteristics (“easy-in, easy-out”) in multiplayer browser games have been suggested as the main cause for en-joyment in Germany (17) Game and internet addictions are also connected with interpersonal relationship patterns (18) Compe-tition, in contrast, seems to be less important for browser gamers than for users of other game types There is only weak evidence for the assumption that aggressive behavior is associated with excessive gaming (9) Excessive computer game playing could result in deficient visual-spatial ability (19)

HEALTH HAZARDS

The medical profession, for over 20 years, has voiced a num-ber of concerns about video game playing Back in the early 1980s, rheumatologists described cases of “Pac-man’s Elbow” and “Space Invaders’ Revenge” in which players have suffered skin, joint, and muscle problems from repeated button hitting and joystick pushing on the game machines (20) Early research

by Loftus and Loftus indicated that two-thirds of (arcade) video game players examined complained of blisters, calluses, sore tendons, and numbness of fingers, hands, and elbows directly as

a result of their playing There have been a whole host of case studies in the medical literature reporting some of the adverse effects of playing video games (21, 22) These have included auditory hallucinations (23), enuresis (24), encoprisis (25), wrist pain (26), neck pain (27), elbow pain (27), tenosynovitis-also called “nintendinitis” (28–31), hand-arm vibration syn-drome (32), repetitive strain injuries (33), and peripheral

neuropathy (34) Recently, there is a study describing ten

pa-tients who experienced epileptic seizures while playing the

newest genre of electronic games Massively Multiplayer Online

Role-Playing Games (MMORPGs) (35) Patients were

predom-inantly young, male adults, and most of the events were

gener-alized tonic-clonic seizures, myoclonic seizures, and absences

The author suggested that while the prevalence of

MMORPG-induced seizures remains unknown, there should be an

aware-ness of this special form of reflex seizures in order to provide

an appropriate health warning to MMORPG players

PREVENTION AND TREATMENT

There is preliminary evidence for success of an “initiated

ab-stinence” program in 12–15 year old pupils in Austria, Germany,

and Italy (36) Some countries like the United States, Canada,

China, Korea, and the Netherlands have opened treatment

cen-ters for video game addiction In 2009, ReSTART has set up

a residential treatment center in Seattle, WA for pathological

internet use There is little evidence for psychological or

phar-macological treatment for video and computer game addiction

A study using methylphenidate in 62 Korean children diagnosed

with ADHD and internet video game addiction was reported (2)

After 8 weeks of treatment, measures of internet use scores and

internet usage times were significantly reduced, and these

mea-sures were positively correlated with meamea-sures of attention The

authors suggest that internet video game playing might be a

means of self-medication for children with ADHD In addition,

they cautiously suggest that Methylphenidate (MPH) might be

evaluated as a potential treatment of Internet addiction In

sum-mary, there are very few clinical trials and no meta-analyses on

treatment for excessive computer game addiction

MOTORBIKE-RIDING COMPUTER GAME FOR

QUANTIFYING DOPAMINE RELEASE: RATIONALE AND

AIMS OF THE STUDY

Chronic use of psycho-stimulants such as cocaine and

methamphetamine results in long-term effects to the dopamine

reward system For example, compared to healthy subjects,

detoxified cocaine-dependent subjects exhibit reduced striatal

D2 receptor availability (37–39) and decreased drug-induced

dopamine release (39, 40) Currently, there is evidence that

ab-stinent “ecstasy” users with a history of using sequential

“ec-stasy” doses had no reductions in striatal dopamine transporter

(DAT) binding (41) Since other stimulant drug abusing

popu-lations show evidence of diminished dopamine responsiveness

we have decided to test whether this observation extends to

“ecstasy” abusers in response to a non-drug reward/challenge

We hypothesized that chronic use of “ecstasy,” similar to other

psycho-stimulants such as cocaine and methamphetamine might

result in long-term changes to the dopaminergic reward system

The effects of “ecstasy”-induced alterations on the dopamine

reward circuit (basal ganglia-thalamo-cortical circuit) are

potentially secondary to the neurotoxic effects of “ecstasy” on 5-HT signaling

We, therefore, decided to investigate dopamine release in the brain during playing of a motorbike riding computer game Be-cause some subjects were former chronic users of MDMA (“ec-stasy”), we were also able to evaluate whether past chronic use

of “ecstasy” had any long-term effects on game performance, levels of dopamine receptor occupancy, or dopamine release in the striatum during game playing

Unfortunately, our study did not include computer game play-ers since our grant was limited to investigate drug addiction

BEHAVIORALLY-INDUCED DOPAMINE-RELEASE IN THE BRAIN’S REWARD SYSTEM

The quantification of dopamine release in the human brain

is now possible due to brain imaging techniques that mea-sure dopamine D2receptor availability in human subjects using dopamine competition with either [123I] IBZM (a D2 receptor antagonist radiotracer) in single photon emission computed to-mography (SPECT) (42) or [11C] raclopride in positron emission tomography (PET) Either [123I] IBZM or [11C] raclopride bind-ing is sensitive to endogenous DA concentration; this procedure can also be used to measure relative changes in DA concentra-tion secondary to pharmacological or behavioral intervenconcentra-tions Playing a computer tank riding game can release dopamine in vivo in the human brain comparable to the dopamine released as

a result of pharmacological challenge with amphetamines (43) Behavioral paradigms, such as playing a video game (43), mon-etary reward tasks (44), and non-hedonic food motivation (45) also release dopamine in brain meso-limbic reward centers

PROCEDURE Subjects

Nine former “ecstasy” users (mean age 25 years (SD= 3.5);

8 males, 1 female) verified abstinent up to 1.5 years (mean= 5 months, range 1–18 months) and eight control subjects (mean

age 35.75 years(SD= 6.5); 7 males, 1 female) Former “ecstasy” users had less education (12 (.9) years) than control subjects (13.75 (1.6) years) Ex-“ecstasy” users used on average 220

“ecstasy” tablets (range 30–600) in their life, and total number

of tablets in their lifetime was 428.5 (range 30–1500) They

used “ecstasy” on average for 12 years and 3 months (SD = 92) They reported on average 7 times of using “ecstasy” in a

month during their last year of use before treatment (SD= 3.3) and time since last use was on average 5 months (range 1–18 months) A list of all substances used by ex-”ecstasy” users is presented in Table 1

The former “ecstasy”-users, recruited from drug treatment centers Control subjects were recruited through advertisement

in treatment centers and the hospital They reported no current

or recent use of “ecstasy” or marijuana Five of the ex-“ecstasy” patients were treated with antidepressant medication (Sertraline,

TABLE 1.

List of drugs and alcohol use among ex-“ecstasy” users

Venlafaxine, Fluoxetine, and Escitalopram) and six of them were

treated with relaxants (Clonazepam and Diazepam) They were

scanned six months after treatment when they were not taking

medication

Behavioral Computerized Game

Commercially available motorbike-riding computerized

video game by “motogp” ultimate racing technology

(www.THQ.Co.UK) using a joystick The time it took to

com-plete each track on the racing field was recorded on the computer

Procedure

Eligible subjects gave written informed consent and were

admitted to the hospital at 10 a.m Starting at 10:30 a.m., they

received a bolus injection of 5–6 mCi of [123I] IBZM, followed

by constant infusion of 5–6 mCi of [123I] IBZM (1.7–2 mCi/hr

for three hours while resting on a hospital bed Due to problems

with radiation safety in our brain imaging facility, we were not

able to continue with constant infusion beyond 3 hours

postin-jection We are not aware of any literature precedents for using

an altered [123I] IBZM infusion protocol like ours In healthy

volunteers who were injected with bolus [123I] IBZM without

constant infusion, pseudo-equilibrium was achieved at 90 min

post-bolus injection of [123I] IBZM, and it was maintained

un-til the end of the SPECT session at 3 hours postinjection (46)

In our study, due to the termination of constant infusion after

3 hours, there is a possibility of a higher rate of washout of

the tracer from the plasma, which might have affected the

re-sults However, there is evidence that postinfusion equilibrium

is maintained, and the washout rate of the tracer from the plasma

may have been minimal, and it may have not affected our results

(47) After a baseline SPECT scan, they returned to their room

and played the motorbike-riding computer game for 40 minutes

After game playing, they had a second SPECT scan, followed

after 15 minutes of rest by a third SPECT scan

Image Analysis

A measure of dopamine receptor occupancy obtained without plasma measurements is the specific to nonspecific equilibrium partition coefficient, V3”, which is a measure of dopamine D2 receptor availability and can be calculated from: V3”= (S – O)/O, where S and O are activity concentrations in the striatum and occipital cortex, respectively (42) This calculation has been shown to give accurate values of V3” under equilibrium condi-tions Its accuracy is not known under the conditions of this study, where infusion was stopped before the first scan All im-ages were registered and normalized to an IBZM template (48) using the preprocessing tools of Statistical Parametric Mapping (SPM) The image comparisons were then performed using the MarsBaR tool within SPM

RESULTS

First, at baseline, there was no significant difference in D2 receptor occupancy, i.e., partition coefficient (V3”), in absti-nent “ecstasy” users compared with control subjects (.71 and 86, respectively) Second, during performance of the video game, there was a 10.5% reduction, compared to baseline, in the partition coefficient (V3”) in control subjects in the cau-date, consistent with increased dopamine release and binding to the D2receptors In control subjects, there were lower rates of binding potential after motorbike riding game compared with baseline (scan 1 versus scan 2) in the right caudate t (1,7)= 2.56;

p < 05 There was no reduction in the abstinent “ecstasy” users

after performance of the video game in all parts of the striatum Third, D2receptor levels have not returned to baseline after the third scan in control subjects consistently with results reported

by a previous study (22) Fourth, there was significant correla-tion between performance measures (reaccorrela-tion time on the video game) of all subjects and baseline measures of binding

poten-tials (scan 1) in the right caudate (r = 70; p < 001), left caudate (r = 67; p < 01), right putamen (r = 68; p < 01), and left putamen (r = 72; p < 001) Finally, there was no difference

Right caudate

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

scan3 scan2

scan1

controls patients

Left caudate

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

scan3 scan2

scan1

controls patients

Right putamen

0 0.2 0.4 0.6 0.8 1 1.2

scan3 scan2

scan1

controls patients

Left putamen

0 0.2 0.4 0.6 0.8 1

scan3 scan2

scan1

controls patients

Figure 1 Measures of partition coefficient (V3”) in control subjects and ex-“ecstasy” patients in the caudate and putamen divided by laterality in all scans (1, 2, and 3).

in performance (reaction-time) between the two groups on the

motorbike video game

Figure 1 shows measures of partition coefficient (V3”) in

control subjects and abstinent “ecstasy” patients in the caudate

and putamen divided by laterality in all scans (1, 2, and 3)

Table 2 shows average V3” measures and standard deviations

in the caudate putamen in control subjects and ex-“ecstasy”

users in all scans

DISCUSSION

Control subjects had significant 10.5% reduction in bind-ing potential measure in the caudate after performance com-pared with their baseline measure, consistent with the results reported by a previous study (43) that showed 13% reduction of binding potential in the ventral striatum after video game perfor-mance This is comparable to measures of dopamine release pro-duced by amphetamine (49) or methylphenidate (50, 51) This

TABLE 2.

Average V3” measures in the caudate putamen in control subjects and ex-“ecstasy” users in all scans

Control

subjects

mean

Ex-“ecstasy”

subjects

mean

Control

subjects

mean

Ex-“ecstasy”

subjects

mean

finding implies that video game playing is capable of significant

dopamine release that is comparable to the effects of

psycho-stimulant drugs on the brain It is plausible that individuals who

are addicted to video-game playing derive much pleasure from

playing these games due to extensive dopamine release In

con-trast, former “ecstasy” users showed little change in D2binding

potential in the caudate/putamen in response to video game

per-formance This finding implies low brain dopamine response

to natural reward presumably due to previous sensitization to

stimulant drugs that release a great amount of dopamine in their

brain over time

The finding of correlation between reaction time

measure-ments and the baseline scan V3” for both cohorts merits further

consideration Our findings suggest that there was no effect of

game playing on changes in V3” in ex-“ecstasy” users, even

though their reaction times like comparison subject reaction

times were correlated with baseline scan V3” These findings

taken altogether may imply at least a partial dissociation

be-tween the reward and motor system consequences of “ecstasy”

use

There are several limitations to our study First, our

ex-“ecstasy” patients have used other drugs than “ecstasy,” which

may have affected measures of binding potential especially

in the case of marijuana Secondly, most ex-“ecstasy” users

have been treated with Selective Serotonin Reuptake Inhibitors

(SSRIs) or relaxant medication (benzodiazepines), and these

medications are known to interact with the dopamine system,

although they were not medicated during scanning Thirdly,

the ex-“ecstasy” users were younger than control subjects, but

that would only mean that their dopamine receptor occupancy

should be higher than control subjects (dopamine transporter

availability measures decline about 6.6% every 10 years) (52) Fourthly, since there was only one female subject in each group, and they were both pre-menopausal, this may have affected the results, but there is no evidence for any menstrual-cycle-dependent variation in D2receptor density detectable with single PET [11C] Raclopride (53) Fifthly, the second and third scans were not performed under ideal conditions of equilibrium, and this may have affected the results due to higher rates of washout Finally, this is a small sample even for a brain imaging study due to strict selection criteria

OVERALL DISCUSSION

Computer or video game addiction, which is excessive or compulsive use of computer and video games with resulting adverse consequences, is not clinically defined as a part of be-havioral addictions in DSM-IV There is no official diagnosis

or definition of the disorder in any official diagnostic system There were several studies investigating the prevalence of this disorder; however, they used different scales adapted from the DSM-III-R criteria for pathological gambling or other addic-tions to create diagnostic questionnaires People like computer game playing and become addicted to it due to repetition of favorable activities or emotional experiences, experiences of fulfillment, social relationship, and flexibility, while the aspects

of competition and aggression have been discounted

Three different mechanisms have been suggested as driving excessive computer gaming, although there have been very few psycho-physiological investigations of these underlying mech-anisms First, it has been suggested that computer games are inadequate means of coping with frustration, stress, and fears

(5) The excessive usage of computer and video games is seen as

a rewarding behavior which can, due to learning mechanisms,

become a prominent and inadequate strategy for 11 to 14 year

old children to cope with negative emotions like frustration,

un-easiness, and fears Like substance abuse or addiction, excessive

computer and video game players use their excessive rewarding

behavior specifically as an inadequate stress coping strategy It is

also known that computer game addiction decreased the quality

of interpersonal relationships and the amount of social anxiety

increased as the amount of time spent playing online games

increased (54) Secondly, and consistent with the stress-coping

explanation, it has been suggested that in-game reinforcement

and skill significantly influence a number of affective measures,

most notably excitement, arousal, and frustration (55) Thirdly,

excessive computer game playing may be maintained through

effects on reward and sensitization (56), similar to the

long-term changes in the brain reward circuitry thought to maintain

substance dependence Electroencephalographic recordings in

computer game players have shown increased emotional

pro-cessing of computer-related cues in parietal brain regions in

pathologically excessive players compared with casual

play-ers Furthermore, when participants with online game addiction

were presented with gaming pictures and mosaic control

pic-tures while undergoing functional magnetic resonance imaging

(fMRI), they have shown activation of the brain’s craving areas

including the right orbito-frontal cortex, right nucleus

accum-bens, bilateral anterior cingulate and medial frontal cortex, right

dorso-lateral prefrontal cortex, and right caudate nucleus (57)

Thus, the results suggest that the gaming urge/craving in online

gaming addiction and craving in substance dependence might

share the same neurobiological mechanism

Finally, in an functional Magnetic Resonance Imaging

(fMRI) study contrasting a space-infringement game with a

control task, males showed greater activation and functional

connectivity compared to females in the meso-cortico-limbic

system (58) These findings may be attributable to higher

moti-vational states in males, as well as gender differences in reward

prediction, learning reward values, and cognitive state during

computer video game playing These gender differences may

help explain why males are more attracted to, and more likely

to become “hooked” on video games

The reward and sensitization explanation is consistent with

growing evidence that computer game playing addiction,

sim-ilar to other behavioral addictions like compulsive gambling,

overeating, sex, and shopping, leads to long-term changes in

the reward circuitry that resemble the effects of substance

dependence Advanced brain imaging techniques using the

dopamine-competition paradigm can quantify dopamine

re-lease as result of computer game playing So far, playing

com-puter games in healthy volunteers has shown dopamine release

in the striatum to a similar extent as pharmacological

chal-lenge, whereas we have shown that former chronic users of

“ecstasy” released very little dopamine after performance of a

computer game We speculate that, similar to psycho-stimulant

abusers, individuals diagnosed with behavioral addictions such

as gambling and computer game addiction would show reduced dopamine release after performance of video games or gam-bling presumably due to sensitization Future research could investigate these individuals and could give a psycho-biological explanation to this emerging object of scientific research

ACKNOWLEDGMENT

We would like to thank Shaul Schreiber, Isachar Herman, Omri Frisch, and Eitan Ekstein for providing access to their patients We would like to thank the staff at the Departments of Nuclear Medicine at Sourasky Medical Center and Hadassah Hospital, particularly Einat Even-Sapir, Mazal Greemland, Hedva Lerman, Yodphat Krausz, and Boris Bakunin We would also like to thank David Nutt and Paul Grasby for early dis-cussions and initiation of the study, John Seibyl for advice concerning imaging, Nanette Freedman and Elisheva Deutz for image analysis, and Marko Leyton and Mike Morgan for useful comments on the manuscript Preliminary results of this study were presented at the College of Problems of Drug Dependence annual meeting, Orlando, FL, June 2005 and the European Col-lege of Neuropsychopharmacology annual meeting in Vienna, Austria, October 2007

Declaration of Interest

The reported research was funded by a grant from the “Adams Trust” in Tel Aviv University and a grant from the Israeli Anti-Drug Authority

Dr Weinstein is now supported by the Israeli Anti-Drug Authority and the National Institute for Psychobiology in Israel The authors report no conflict of interest The authors alone are responsible for the content and writing of this paper

REFERENCES

1 Griffiths MD A “components” model of addiction within a biopsychosocial

framework Journal of Substance Use 2005; 10:191–197.

2 Griffiths MD Videogame addiction: further thoughts and observations Int

J Ment Health Addiction 2008; 6:182–185.

3 Griffiths MD Videogame addiction: Fact or fiction? In Willoughby T, Wood E, (Eds.) Children’s Learning in a Digital World Oxford: Blackwell Publishing, 2007; pp 85–103.

4 te Wildt BT, Putzig I, Zedler M, Ohlmeier MD Internet dependency as

a symptom of depressive mood disorders Psychiatr Prax 2007; 34(Suppl

3):S318–322 (in German)

5 Han D, Lee Y, Na C, Ahn J, Chung U, Daniels M, Haws C, Renshaw

P The effect of methylphenidate on Internet video game play in

chil-dren with attention-deficit/hyperactivity disorder Compr Psychiatry 2009;

50(3):251–256.

6 Griffiths MD Does Internet and computer “addiction” exist? Some case

study evidence Cyberpsychol and Behav 2000; 3(2):211–218.

7 Griffiths MD The role of context in online gaming excess and

addic-tion: Some case study evidence Int J Ment Health Addiction 2010; 8:119–

125.

8 Grusser SM, Thalemann R, Albrecht U, Thalemann CN Excessive

com-puter usage in adolescents—Results of a psychometric evaluation Wien

Klin Wochenschr 2005; 117(5–6):188–195 (in German)

9 Grusser SM, Thalemann R, Griffiths MD Excessive computer game

play-ing: evidence for addiction and aggression? Cyberpsycho Behav 2007;

10(2):290–292.

10 Woelfling K, Thalemann R, Grusser SM Computer game addiction: A

psychopathological symptom complex in adolescence Psychiat Prax 2008;

35(5):226–232 (in German)

11 Johansson A, G¨otestam KG Problems with computer games without

mon-etary reward: similarity to pathological gambling Psychol Rep 2005;

95(2):641–650.

12 Griffiths MD, Hunt N Dependence on computer games by adolescents.

Psychol Rep 1998; 82(2):475–480.

13 Rehbein F, Kleimann M, M¨oßle T Prevalence and Risk Factors of Video

Game Dependency in Adolescence: Results of a German Nationwide

Sur-vey Cyberpsychology, Behavior, and Social Networking [ePub ahead of

print] doi:10.1089/cpb.2009.0227.

14 Tahiroglu AY, Celik GG, Uzel M, Ozcan N, Avci A Internet use among

Turkish adolescents Cyberpsychol Behav 2008; 11(5):537–543.

15 Chou TJ, Ting CC The role of flow experience in cyber-game addiction.

Cyberpsychol Behav 2003; 6(6):663–675.

16 Wan CS, Chiou WB Why are adolescents addicted to online gaming? An

interview study in Taiwan Cyberpsychol Behav 2006; 9(6):762–766.

17 Klimmt C, Schmid H, Orthmann J Exploring the enjoyment of playing

browser games Cyberpsychol Behav 2009; 12(2):231–234.

18 Lee M, Ko Y, Song H, Kwon K, Lee H, Nam M, Jung I Characteristics of

Internet use in relation to game genre in Korean adolescents Cyberpsychol

Behav 2007; 10(2):278–285.

19 Sun DL, Ma N, Bao M, Chen XC, Zhang DR Computer games: A

double-edged sword? Cyberpsychol Behav 2008; 11(5):545–548.

20 Loftus GA, Loftus EF Mind at Play: The Psychology of Video Games.

New York: Basic Books, 1983.

21 Griffiths M, Wood RTA Risk factors in adolescence: the case of

gam-bling, videogame playing and the Internet J Gambling Studies 2000;

16(2–3):199–225.

22 Griffiths MD, Meredith A Videogame Addiction and its treatment J

Con-temp Psychother 2009; 39:247–253.

23 Spence SA Nintendo hallucinations: A new phenomenological entity Irish

Journal of Psychological Medicine 1993; 10:98–99.

24 Schink JC Nintendo enuresis American Journal of Diseases in Children

1991; 145:1094.

25 Corkery JC Nintendo power American Journal of Diseases in Children,

1990; 144:959.

26 McCowan TC Space Invaders wrist New England Journal of Medicine

1981; 304:1368.

27 Miller DLG Nintendo neck Canadian Medical Association Journal

1991;145:1202.

28 Reinstein L de Quervain’s stenosing tenosynovitis in a video games player.

Archives of Physical and Medical Rehabilitation 1983; 64:434–435.

29 Brasington R Nintendinitis New England Journal of Medicine 1990;

322:1473–1474.

30 Casanova J, Casanova J Nintendinitis Journal of Hand Surgery 1991;

16:181.

31 Siegal IM Nintendonitis Orthopedics 1991; 14:745.

32 Cleary AG, Mckendrick H., Sills JA Hand-arm vibration syndrome may

be associated with prolonged use of vibrating computer games British

Medical Journal 2002; 324:301.

33 Mirman MJ, Bonian VG “Mouse elbow:” A new repetitive stress

in-jury The Journal of the American Osteopathic Association 1992; 92:

701.

34 Friedland RP, St John, JN Video-game palsy: Distalulnar neuropathy in

a video game enthusiast New England Journal of Medicine 1984; 311:

58–59.

35 Chuang YC Massively multiplayer online role-playing game-induced

seizures: A neglected health problem in Internet addiction Cyberpsychol

Behav 2006; 9(4):451–456.

36 Kalke J, Raschke P Learning by doing: ‘initiated abstinence,’ a school-based programme for the prevention of addiction Results of an evaluation

study Eur Addict Res 2004; 10(2):88–94.

37 Volkow ND, Fowler JS, Wolf AP, Schlyer D, Shiue CY, Alpert R Effects of

chronic cocaine abuse on postsynaptic dopamine receptors Am J Psychiatry 1990; 147:719–724.

38 Volkow ND, Fowler JS, Wang GJ, Hitzemann R, Logan J, Schyler

DJ Decreased dopamine D2 receptor availability is associated with

re-duced frontal metabolism in cocaine abusers Synapse1993; 14:169–

177.

39 Volkow ND, Wang GJ, Fowler, JS, Logan J, Gatley SJ, Hitzemann R Decreased striatal dopaminergic responsiveness in detoxified

cocaine-dependent subjects Nature 1997; 386:830–833.

40 Martinez D, Broft A, Foltin RW, Slifstein M, Hwang D-R, Huang Y, Perez

A, Frankel WG, Cooper T, Kleber HD, Fischman MW, Laruelle M Cocaine dependence and D2 receptor availability in the functional subdivisions of the

striatum: Relationship with cocaine-seeking behavior

Neuropsychophar-macology 2004; 29:1190–1202.

41 McCann UD, Szabo Z, Vranesic M, Palermo M, Mathews WB, Ravert

HT, Dannals RF, Ricaurte GA Positron emission tomographic stud-ies of brain dopamine and serotonin transporters in abstinent ( +/−)3,4-methylenedioxymethamphetamine (“ecstasy”) users: relationship to

cog-nitive performance Psychopharmacology (Berl) 2008; 200(3):439–

450.

42 Laruelle M, Abi-Dargham A, van Dyck CH, Rosenblatt W, Zea-Ponce Y, Zoghbi SS, Baldwin RM, Charney DS, Hoffer PB, Kung HF, Innis RB SPECT imaging of striatal dopamine release after amphetamine challenge.

J Nuc Med 1995; 36:1182–1190.

43 Koepp MJ, Gunn RN, Lawrence AD, Cunningham VJ, Dagher A, Jones T, Brooks DJ, Bench CJ, Grasby PM Evidence for striatal dopamine release

during a video game Nature 1998; 393:266–268.

44 Zald DH, Boileau I, El-Dearedy W, Gunn R, McGlone F, Dichter

GS, Dagher A Dopamine transmission in the human striatum

dur-ing monetary reward tasks J Neuroscience 2004; 24(17):4105–

4112.

45 Volkow ND, Wang G-J, Fowler JS, Logan J, Jayne M, Franchesi D, Wong C, Gatley SJ, Gifford AN, Ding Y-S, Pappas N “Nonhedonic” food motivation

in humans involves dopamine in the dorsal striatum and methylphenidate

amplifies this effect Synapse 2002; 44:175–180.

46 Catafau AM, Bullich S, Dan´us M, Penengo MM, Cot A, Abanades S, Farr´e M, Pav´ıa J, Ros D Test-retest variability and reliability of 123I-IBZM SPECT measurement of striatal dopamine D2 receptor availability

in healthy volunteers and influence of iterative reconstruction algorithms.

Synapse 2008; 62(1):62–69.

47 Seibyl JP, Zea-Ponce Y, Brenner L, Baldwin RM, Krystal JH, Offord SJ, Machoviak S, Charney DS, Hoffer PB, Innis RB Continuous intravenous infusion of Iodine-123-IBZM for SPECT determination of human brain

dopamine receptor occupancy by antipsychotic agent RWJ-37796 J Nuc

Med 1996; 37:11–15.

48 Buchert R, Berding G, Wilke F, Martin B, von Borczyskowski D, Mester

J, Brenner W, Clausen M IBZM tool: A fully automated expert system

for the evaluation of IBZM SPECT studies Euro J Nuc Med Mol Imaging 2006; 33(9):1073–1083.

49 Farde L, Nordstr¨om, AL, Wiesel FA, Pauli S, Halldin C, Sedvall G Positron emission tomography analysis of central D1 and D2 dopamine receptor occupancy in patients treated with classical neuroleptics and clozapine.

Arch Gen Psychiat 1992; 49:538–544.

50 Volkow ND, Wang GJ, Fowler JS, Logan J, Schlyer D, Hitzemann R, Lieberman J, Angrist B, Pappas N, MacGregor R, et al Imaging endogenous

dopamine competition with [11 C] raclopride in the human brain Synapse 1994; 16:255–262.

51 Booij J, Korn P, Linszen DH, van Royen EA Assessment of

endoge-nous dopamine release by methylphenidate challenge using iodine-123

iodobenzamide single-photon emission tomography Euro J Nuc Med 1997;

24(6):674–677.

52 Volkow ND, Ding YS, Fowler JS, Wang GJ, Logan J, Gatley SJ, Hitzemann

R, Smith G, Fields SD, Gur R Dopamine transporters decrease with age J

Nuc Med 1996; 37(4):554–559.

53 Nordstrom A-L, Olsson H, Halldin C, A PET study of D2dopamine

re-ceptor density at different phases of the menstrual cycle Psychiat Res

(Neuroimaging) 1998; 83:1–6.

54 Lo SK, Wang CC, Fang W Physical interpersonal relationships and social

anxiety among online game players Cyberpsychol Behav 2005; 8(1):15–20.

55 Chumbley J, Griffiths M Affect and the computer game player: The effect

of gender, personality, and game reinforcement structure on affective

re-sponses to computer game-play Cyberpsychol Behav 2006; 9(3):308–316.

56 Thalemann R, Wolfling K, Grusser SM Specific cue reactivity on

com-puter game-related cues in excessive gamers Behav Neurosci 2007;

121(3):614–618.

57 Ko CH, Liu GC, Hsiao S, Yen JY, Yang MJ, Lin WC, Yen CF, Chen CS.

Brain activities associated with gaming urge of online gaming addiction J

Psychiatr Res 2009; 43(7):739–747.

58 Hoeft F, Watson CL, Kesler SR, Bettinger KE, Reiss AL Gender differences

in the mesocorticolimbic system during computer game-play J Psychiat

Res 2008; 42(4):253–258.