Kimberly Young indicates that previous research links internet/computer addiction with existing mental health issues, most notably depression. She states that computer addiction has significant effects socially such as low self-esteem, psychologically and occupationally which led many subjects to academic failure.

According to a Korean study on internet/computer addiction, pathological use of the internet results in negative life impacts such as job loss, marriage breakdown, financial debt, and academic failure. 70% of internet users in Korea are reported to play online games, 18% of which are diagnosed as game addicts which relates to internet/computer addiction. The authors of the article conducted a study using Kimberly Young's questionnaire. The study showed that the majority of those who met the requirements of internet/computer addiction suffered from interpersonal difficulties and stress and that those addicted to online games specifically responded that they hoped to avoid reality.

The rate of people who have problems of shopping addiction is a very controversial matter, because the dividing line between pathological behaviours and those behaviours which, even if excessive, are socially accepted, is very difficult to determine. However, shopping addiction and other manifestations of the lack of self-control on spending are widespread problems which are constantly expanding. Studies using samples of the general population show that between 8% and 16% of the people have problems with excessive or uncontrolled purchases. Clinical studies give much lower figures, however, between 2% and 5%. According to the European Report on the programme for the prevention and treatment of personal problems related to consumer addiction, personal purchasing habits and over-indebtedness, 3% of European adults and 8% of European young people have a level of shopping addiction which could be considered as pathologic, that is, which seriously affects the life of the people who suffer from this. Other estimates for the prevalence of compulsive buying range from a low of 2 percent to 12 percent or more (in the U.S. population.

Most of people who have these problems neither receive nor ask for treatment. Those that ask for help only do it after years of suffering, when the addiction has caused very serious economic repercussion and has harmed the relationship with their family and social environment. For this reason and due to the lack of social consciousness about this problem, the unrecorded figure of people who suffer from these problems is very high. In addition to the severe cases of shopping addiction, an important part of consumers (between 30% and 50% of the population) have deficiencies with spending self-control or excessive purchases. According to the European Report, 33% of European adults and 46% of the European young people have minor or moderate problems with shopping addiction or lack of economic self-control.

Prevalence of mobile phone overuse depends largely on definition and thus the scales used to quantify a subject's behaviors. Two scales are in use, the 20-item self-reported Problematic Use of Mobile Phones (PUMP) scale, and the Mobile Phone Problem Use Scale (MPPUS), which have been used both with adult and adolescent populations. There are variations in the age, gender and percentage of the population affected problematically according to the scales and definitions used. The prevalence among British adolescents aged 11–14 was 10%. In India, addiction is stated at 39-44% for this age group. Under different diagnostic criteria, the estimated prevalence ranges from 0 to 38%, with self-attribution of mobile phone addiction exceeding the prevalence estimated in the studies themselves. The prevalence of the related problem of Internet addiction was 4.9-10.7% in Korea, and is now regarded as a serious public health issue.

Behaviors associated with mobile-phone addiction differ between genders. Women are more likely to develop addictive mobile phone behavior than men. Men experience less social stress than women and use their mobile phones less for social purposes. Older people are less likely to develop addictive mobile phone behavior because of different social usage, stress and greater self-regulation.

Overuse is often defined as a "dependence syndrome," which is the term used by the World Health Organization (WHO Expert Committee, 1964) to replace "addiction" or "habituation." This is categorised either as substance abuse, such as from psychoactive drugs, alcohol and tobacco under ICD-10, or a behavioral addiction, such as a mobile phone addiction.

Substance use disorders can be defined by 11 factors, according to the DSM-5, including: (1) use in larger quantities or for longer than initially intended, (2) a desire to cut down or control use, (3) spending a great deal of time obtaining, using, or recovering from the substance, (4) craving, (8) use in situations in which it is physically hazardous, (9) continued use of the substance despite adverse physical or psychological consequences associated with use, and (11) withdrawal symptoms.

Smartphone addiction can be compared to substance use disorders in that smartphones provide the drug (entertainment and connection) while acting as the means by which the drug is consumed. A study conducted at Alabama State University on the effects of smartphones on students, defines the issue by stating that we are not addicted to smartphones themselves, but that we "are addicted to the information, entertainment, and personal connections [that a smartphone] delivers." People have an affinity for constant entertainment, and smartphones provide the quickest, most easily accessible route to it.

In Europe, the rate of problem gambling is typically 0.5 to 3 percent. The "British Gambling Prevalence Survey 2007", conducted by the United Kingdom Gambling Commission, found approximately 0.6 percent of the adult population had problem gambling issues—the same percentage as in 1999. The highest prevalence of problem gambling was found among those who participated in spread betting (14.7%), fixed odds betting terminals (11.2%) and betting exchanges (9.8%). In Norway, a December 2007 study showed the amount of present problem gamblers was 0.7 percent.

Some scholars believe that codependency is not a negative trait, and does not need to be treated, as it is more likely a healthy personality trait taken to excess. Codependency in nonclinical populations has some links with favourable characteristics of family functioning.

Stan Katz states that codependence is over-diagnosed, and that many people who could be helped with shorter-term treatments instead become dependent on long-term self-help programs. The language of, symptoms of, and treatment for codependence derive from the medical model suggesting a disease process underlies the behavior. However, there is no evidence that codependence is caused by a disease process.

In their book, “Attached.”, Dr. Amir Levine and Rachel S. F. Heller, address what they call the “codependency myth” by asserting that attachment theory is a more scientific and helpful model for understanding and dealing with attachment in adults.

The American Psychiatric Association decided that enough evidence exists to propose the potential disorder of video game addiction as a "condition requiring further study" in the "Diagnostic and Statistical Manual of Mental Disorders" as Internet gaming disorder. Video game addiction is a broader concept than internet gaming addiction, but most video game addiction is associated with Internet gaming. APA suggests, like Khan, the effects (or symptoms) of video game addiction may be similar to those of other proposed psychological addictions. Video game addiction may be an impulse control disorder, similar to compulsive gambling APA explains why Internet gaming disorder has been proposed as a disorder:

Excessive use of video games may have some or all of the symptoms of drug addiction or other proposed psychological addictions.

Some players become more concerned with their interactions in the game than in their broader lives. Players may play many hours per day, neglect personal hygiene, gain or lose significant weight due to playing, disrupt sleep patterns to play resulting in sleep deprivation, play at work, avoid phone calls from friends, or lie about how much time they spend playing video games.

APA has developed 9 criteria for characterizing the proposed Internet gaming disorder:

1. Pre-occupation. Do you spend a lot of time thinking about games even when you are not playing, or planning when you can play next?

2. Withdrawal. Do you feel restless, irritable, moody, angry, anxious or sad when attempting to cut down or stop gaming, or when you are unable to play?

3. Tolerance. Do you feel the need to play for increasing amounts of time, play more exciting games, or use more powerful equipment to get the same amount of excitement you used to get?

4. Reduce/stop. Do you feel that you should play less, but are unable to cut back on the amount of time you spend playing games?

5. Give up other activities. Do you lose interest in or reduce participation in other recreational activities (hobbies, meetings with friends) due to gaming?

6. Continue despite problems. Do you continue to play games even though you are aware of negative consequences, such as not getting enough sleep, being late to school/work, spending too much money, having arguments with others, or neglecting important duties?

7. Deceive/cover up. Do you lie to family, friends or others about how much you game, or try to keep your family or friends from knowing how much you game?

8. Escape adverse moods. Do you game to escape from or forget about personal problems, or to relieve uncomfortable feelings such as guilt, anxiety, helplessness or depression?

9. Risk/lose relationships/opportunities. Do you risk or lose significant relationships, or job, educational or career opportunities because of gaming?

One of the most commonly used instruments for the measurement of addiction, the PVP Questionnaire (Problem Video Game Playing Questionnaire), was presented as a quantitative measure, not as a diagnostic tool.

According to Griffiths, "all addictions (whether chemical or behavioral) are essentially about constant rewards and reinforcement". Griffiths proposed that addiction has six components: salience, mood modification, tolerance, withdrawal, conflict, and relapse. But, APA's 9 criteria for diagnosing Internet gaming disorder were made by taking point of departure in 8 different diagnostic/measuring tools proposed in other studies. Thus, APA's criteria attempt to condense the scientific work on diagnosing Internet gaming disorder.

The World Health Organization (WHO) has also proposed possible categories for "gaming disorder" for the forthcoming International Statistical Classification of Diseases and Related Health Problems (ICD). A group of 26 scholars wrote an open letter to the WHO, suggesting that the proposed diagnostic categories lacked scientific merit and were likely to do more harm than good. A December 2017 draft of ICD-11 submitted to WHO approval (expected by 2018) includes "gaming addiction", defined as "a pattern of persistent or recurrent gaming behaviour ('digital gaming' or 'video-gaming')", defined by three criteria: the lack of control of playing video games, priority given to video games over other interests, and inability to stop playing video games even after being affected by negative consequences.

Some theorists focus on presumed built-in reward systems of the games to explain their potentially addictive nature. Many video games, particularly massively multiplayer online role-playing games and social network and mobile games, rely on a "compulsion loop" or "core loop", a cycle of activities that involve rewarding the player and driving them to continue through another cycle, retaining them in the game. The anticipation of such rewards can create a neurological reaction that releases dopamine into the body, so that once the reward is obtained, the person will remember it as a pleasurable feeling. This has been found similar to the same neurological reaction believed to be associated with gambling addiction. In reference to gamers such as one suicide in China, the head of one software association was quoted, "In the hypothetical world created by such games, they become confident and gain satisfaction, which they cannot get in the real world."

Griffiths has also proposed that another reason why online video games are potentially addictive is because they "can be played all day every day". The fact that there is no end to the game can feel rewarding for some, and hence players are further engaged in the game.

A high prenatal testosterone load may be a risk factor for the development of video game addiction in adulthood.

Ferguson, Coulson and Barnett in a meta-analytic review of the research, concluded that the evidence suggests that video game addiction arises out of other mental health problems, rather than causing them. Thus it is unclear whether video game addiction should be considered a unique diagnosis.

Researchers at the University of Rochester and Immersyve, Inc. (a Celebration, Florida, computer gaming think-tank) investigated what motivates gamers to continue playing video games.

According to lead investigator Richard Ryan, they believe that players play for more reasons than fun alone.

Ryan, a motivational psychologist at Rochester, says that many video games satisfy basic psychological needs, and players often continue to play because of rewards, freedom, and a connection to other players.

Michael Brody, M.D., head of the TV and Media Committee of the American Academy of Child and Adolescent Psychiatry, stated in a 2007 press release that "... there is not enough research on whether or not video games are addictive". However, Brody also cautioned that for some children and adolescents, "... it displaces physical activity and time spent on studies, with friends, and even with family".

Karen Pierce, a psychiatrist at Chicago's Children's Memorial Hospital, sees no need for a specific gaming addiction diagnosis. Two or more children see her each week because of excessive computer and video game play, and she treats their problems as she would any addiction. She said one of her excessive-gaming patients "...hasn't been to bed, hasn't showered...He is really a mess".

Research carried out on people undergoing treatment, as well as on the general population has revealed a negative correlation between age and addiction. As the age of people increases there is a lower number of shopping addicts. This data was confirmed by the 1999 European Report.

It must be noted that the age of diagnosis is much later than the age when the problems of addiction begin. Most addicts have the first symptoms of addiction in their twenties, but do not ask for help nor accept treatment until more than ten years afterwards. To explain the higher incidence of shopping addiction in young people, it has been shown that younger people have been born, and have grown up, in an increasingly consumerist society and they have endured the impact of publicity and marketing from birth. On the contrary, it is very unusual to find shopping addiction problems in people older than 65 years.

Computers nowadays rely almost entirely on the internet and thus relevant research articles relating to internet addiction may also be relevant to computer addiction.

- Gaming addiction: a hypothetical behavioral addiction characterized by excessive or compulsive use of computer games or video games, which interferes with a person's everyday life. Video game addiction may present itself as compulsive gaming, social isolation, mood swings, diminished imagination, and hyper-focus on in-game achievements, to the exclusion of other events in life.

- Social media addiction: Data suggest that participants use social media to fulfill their social needs, but are typically dissatisfied. Lonely individuals are drawn to the Internet for emotional support. This could interfere with "real life socializing" by reducing face-to-face relationships. Some of these views are summed up in an Atlantic article by Stephen Marche entitled "Is Facebook Making Us Lonely?", in which the author argues that social media provides more breadth, but not the depth of relationships that humans require and that users begin to find it difficult to distinguish between the meaningful relationships which we foster in the real world, and the numerous casual relationships that are formed through social media.

According to the Productivity Commission's 2010 final report into gambling, the social cost of problem gambling is close to 4.7 billion dollars a year. Some of the harms resulting from problem gambling include depression, suicide, lower work productivity, job loss, relationship breakdown, crime and bankruptcy. A survey conducted in 2008 found that the most common motivation for fraud was problem gambling, with each incident averaging a loss of $1.1 million. According to Darren R. Christensen. Nicki A. Dowling, Alun C. Jackson and Shane A.Thomas a survey done from 1994-2008 in Tasmania gave results that gambling participation rates have risen rather than fallen over this period.

Over the past decade, the concept of Internet addiction has grown in terms of acceptance as a legitimate clinical disorder often requiring treatment. Researchers are divided over whether Internet addiction is a disorder on its own or a symptom of another underlying disorder. There is also debate over whether it should be classified as an impulse-control disorder or an obsessive-compulsive disorder rather than an addiction.

While the existence of Internet addiction is debated, self-proclaimed sufferers are resorting to the courts for redress. In one American case ("Pacenza v. IBM Corp."), the plaintiff argued he was illegally dismissed from his employment in violation of the Americans with Disabilities Act because of Internet addiction triggered by Vietnam War-related post-traumatic stress disorder (PTSD). The case was dismissed by the United States District Court for the Southern District of New York and affirmed on appeal to the United States Court of Appeals, Second Circuit in 2010 (case summarized in Glaser & Carroll, 2007).

About 25% of users fulfill Internet addiction criteria within the first six months of using the Internet. Many individuals initially report feeling intimidated by the computer but gradually feel a sense of "competency and exhilaration from mastering the technology and learning to navigate the applications quickly by visual stimulation" (Beard 374). The feeling of exhilaration can be explained by the way IAD sufferers often describe themselves as: bold, outgoing, open-minded, intellectually prideful, and assertive.

According to a study by Kathy Scherer, a psychologist from the University of Texas at Austin, "13% of college internet users fit the criteria for Internet addicts" (Scherer 1997). In her study, Scherer enlisted the help of 531 college students. She discovered that "72% of the Internet addicted students were men" (Scherer 1997).

The China Communist Youth League claimed in 2007 that over 17% of Chinese citizens between 13 and 17 were addicted to the Internet.

Public concern, interest in, and the study of, Internet over use can be attributed to the fact that it has become increasingly difficult to distinguish between the online and offline worlds. The Internet has tremendous potential to affect the emotions of humans and in turn, alter our self-perception and anxiety levels.

According to Maressa Orzack, director of the Computer Addiction Study at Harvard University's McLean Hospital, between 5% and 10% of Web surfers suffer some form of Web dependency.

According to the Center for Internet Addiction Recovery (whose director is Kimberly S. Young, a researcher who has lobbied for the recognition of net abuse as a distinct clinical disorder), "Internet addicts suffer from emotional problems such as depression and anxiety-related disorders and often use the fantasy world of the Internet to psychologically escape unpleasant feelings or stressful situations." More than half are also addicted to alcohol, drugs, tobacco, or sex.

Mark Griffiths states that "[t]he way of determining whether nonchemical (i.e., behavioral) addictions are addictive in a nonmetaphorical sense is to compare them against clinical criteria for other established drug-ingested addictions", and although his data is dated, and may no longer represent average Internet use accurately, Griffiths comes to the conclusion that the Internet does meet that criteria for addiction in a small number of users.

Scientists have found that compulsive Internet use can produce morphological changes in the structure of the brain. A study which analyzed Chinese college students who had been classified as computer addicts by the study designers and who used a computer around 10 hours a day, 6 days a week, found reductions in the sizes of the dorsolateral prefrontal cortex, rostral anterior cingulate cortex, supplementary motor area and parts of the cerebellum compared to students deemed "not addicted" by the designers. It has been theorized that these changes reflect learning-type cognitive optimizations for using computers more efficiently, but also impaired short-term memory and decision-making abilities—including ones in which may contribute to the desire to stay online instead of be in the real world.

Patricia Wallace PhD, Senior Director, Information Technology and CTY Online, at the Johns Hopkins University Center for Talented Youth argues that based on the case histories that have surfaced, no one denies that excessive involvement with certain psychological spaces on the net can have serious effects on a person's life. She explains that, at a large university in New York, the dropout rate among freshmen newcomers rose dramatically as their investment in computers and Internet access increased, and the administrators learned that 43% of the dropouts were staying up all night on the Internet.

In a codependent relationship, the codependent's sense of purpose is based on making extreme sacrifices to satisfy their partner's needs. Codependent relationships signify a degree of unhealthy "clinginess", where one person does not have self-sufficiency or autonomy. One or both parties depend on their loved one for fulfillment.

Particularly problematic pairings include:

Cash, Rae and Winkler, in a paper titled "Internet Addiction: A brief summary of research and practice", describe early interventions used in the treatment of Internet addiction (IAD), and Internet Gaming Disorder (IGD).

Cognitive Behavior Therapy is designed to help individuals learn how to control their thoughts and feelings. This control is to prevent harmful functions that may trigger impulses to escape into the virtual world. The therapy is setup for three stages. The first stage is to instruct the patient to identify there is a problem and how much a problem computers are creating. Identification is done by using a log to document duration, events, day, of online activity. This can be used to show in black and white how much time is spent online and to help create a realistic goal for patients to strive for. Using this log the patients interact with a therapist to make a schedule for online activity to promote new healthier habits. The second aspect of the treatment program is more for the cognitive aspect, as in, digging into what triggers the excessive online activity. The third phase is to confront or resolve the issues in the patient's life that lead to them seeking escape things via the Internet.

One source states that a major reason the Internet is so appealing is the lack of limits and the absence of accountability.

Professionals generally agree that, for Internet overuse, controlled use is a more practical goal than total abstinence.

Families in the People's Republic of China have turned to unlicensed training camps that offer to "wean" their children, often in their teens, from overuse of the Internet. The training camps have been associated with the death of at least one youth. In November 2009, the government of the People's Republic of China banned physical punishment to "wean" teens from the Internet. Electro-shock therapy had already been banned.

In August 2013, researchers at the MIT Media Lab developed a USB-connected keyboard accessory that would "punish" users – with a small electric jolt – who spent too much time on a particular website.

In July 2014, an internet de-addiction center was started in Delhi, the capital city of India by a non profit organization, Uday Foundation. The Foundation provides counseling to the children and teens with internet addiction disorder.

In August 2009, "ReSTART", a United States-based residential treatment center for "problematic digital media use, internet addiction, and video game addiction", opened near Seattle, Washington, United States. It offers a 7- to 12-week intensive program for adolescents and adults intended to help people set device limits, and address digital distractions.

In 2005, Professor Kiesler called Internet addiction a fad illness. In her view, she said, television addiction is worse. She added that she was completing a study of heavy Internet users, which showed the majority had sharply reduced their time on the computer over the course of a year, indicating that even problematic use was self-corrective.

Most research has focused on adult population or on college students, but little is known about epidemiology of behavioral addictions in adolescence. A study conducted by Villella "et al" looked at a group of students and the prevalence of various addictions. His results showed exercise addiction was the second most prevalent, after compulsive buying.

High risk groups that appear to be addicted to exercise include athletes in sports encouraging thinness or appearance standards, young and middle-age women, and young men.

The consequences of oniomania, which may persist long after a spree, can be devastating, with marriages, long-term relationships, and jobs all feeling the strain. Further problems can include ruined credit history, theft or defalcation of money, defaulted loans, general financial trouble and in some cases bankruptcy or extreme debt, as well as anxiety and a sense of life spiraling out of control. The resulting stress can lead to physical health problems and ruined relationships, or even suicide.

Exercise provides benefits for our bodies, but to some people, the benefits turn into health hazards. To some exercisers, rigorous physical activity becomes the central aspect of their lives. When a preoccupation with exercise has become routine, a person is considered addicted to exercise or exercise dependent. A study done shows why people may become addicted to exercise, especially running. One of the reasons people become addicted to exercise is because of the release of mood-enhancing chemicals known as endorphins. Endorphins increase the sensation of pleasure, which is why people feel good about themselves after they exercise. Endorphins are also responsible for the "runner's high." Recent studies have lent weight to the alternative theory that the addictive appeal of exercise is due to the production of endocannabinoids, naturally produced chemicals that bind to the brain's CB1 receptor, rather than to endorphin production. Those who suffer from exercise addiction will go through physical and emotional withdrawals in the absence of exercise, just like a person who is addicted to other substances, such as drugs or alcohol. Although in many cases, running is a better alternative than substance abuse. The findings in this study conclude that there is a link between negative addiction to running and interpersonal difficulties, which is common in other addictive behaviors as well.

Another form of behavior that is still being investigated is obsessive sun tanning as a behavioral addiction. In a recent study, researchers have proved that many frequent tanners demonstrate signs and symptoms adapted from substance abuse or dependence criteria. Many people who admit to being frequent tanners say they tan to look good, feel good, and to relax. People who partake in excessive tanning are usually completely aware of the health risks associated with it, just like addicted smokers are completely aware of the health risks of smoking. The health hazards are even more severe for high-risk age groups such as teenagers and young adults. Due to the fact that the health risks do not deter tanners from their habit, they are exhibiting self-destructive behavior that resembles the characteristics of those who suffer from substance abuse.

Frequent tanners have said a primary reason why they participate in artificial tanning is to experience the "feel good" feeling tanning salons have to offer. Researchers have found that ultraviolet (UV) radiation from tanning beds offers mood-enhancing effects that act as a treatment for seasonal affective disorder (SAD). SAD is when a person exhibits minor depression during seasonal changes, such as during the winter months. Ultraviolet radiation has been proven to increase the level of melatonin in the body. Melatonin plays a key role in sleep patterns and is suggested to reduce anxiety levels. Thus, those who go tanning experience a sense of relaxation afterwards. This sensation is what possibly drives tanners to continue tanning regardless of the health risks. More research needs to be done, but many researchers are beginning to add tanning to the list of addictive processes.

As demonstrated by the chart below, numerous studies have examined factors which mediate substance abuse or dependence. In these examples, the predictor variables lead to the mediator which in turn leads to the outcome, which is always substance abuse or dependence. For example, research has found that being raised in a single-parent home can lead to increased exposure to stress and that increased exposure to stress, not being raised in a single-parent home, leads to substance abuse or dependence. The following are some, but by no means all, of the possible mediators of substance abuse.

As demonstrated by the chart below, numerous studies have examined factors which moderate substance abuse or dependence. In these examples, the moderator variable impacts the level to which the strength of the relationship varies between a given predictor variable and the outcome of substance abuse or dependence. For example, there is a significant relationship between psychobehavioral risk factors, such as tolerance of deviance, rebelliousness, achievement, perceived drug risk, familism, family church attendance and other factors, and substance abuse and dependence. That relationship is moderated by familism which means that the strength of the relationship is increased or decreased based on the level of familism present in a given individual.

Examples of mediators and moderators can be found in several empirical studies. For example, Pilgrim et al.’s hypothesized mediation model posited that school success and time spent with friends mediated the relationship between parental involvement and risk-taking behavior with substance use (2006). More specifically, the relationship between parental involvement and risk-taking behavior is explained via the interaction with third variables, school success and time spent with friends. In this example, increased parental involvement led to increased school success and decreased time with friends, both of which were associated with decreased drug use. Another example of mediation involved risk-taking behaviors. As risk-taking behaviors increased, school success decreased and time with friends increased, both of which were associated with increased drug use.

A second example of a mediating variable is depression. In a study by Lo and Cheng (2007), depression was found to mediate the relationship between childhood maltreatment and subsequent substance abuse in adulthood. In other words, childhood physical abuse is associated with increased depression, which in turn, in associated with increased drug and alcohol use in young adulthood. More specifically, depression helps to explain how childhood abuse is related to subsequent substance abuse in young adulthood.

A third example of a mediating variable is an increase of externalizing symptoms. King and Chassin (2008) conducted research examining the relationship between stressful life events and drug dependence in young adulthood. Their findings identified problematic externalizing behavior on subsequent substance dependency. In other words, stressful life events are associated with externalizing symptoms, such as aggression or hostility, which can lead to peer alienation or acceptance by socially deviant peers, which could lead to increased drug use. The relationship between stressful life events and subsequent drug dependence however exists via the presence of the mediation effects of externalizing behaviors.

An example of a moderating variable is level of cognitive distortion. An individual with high levels of cognitive distortion might react adversely to potentially innocuous events, and may have increased difficulty reacting to them in an adaptive manner (Shoal & Giancola, 2005). In their study, Shoal and Giancola investigated the moderating effects of cognitive distortion on adolescent substance use. Individuals with low levels of cognitive distortion may be more apt to choose more adaptive methods of coping with social problems, thereby potentially reducing the risk of drug use. Individuals with high levels of cognitive distortions, because of their increased misperceptions and misattributions, are at increased risk for social difficulties. Individuals may be more likely to react aggressively or inappropriately, potentially alienating themselves from their peers, thereby putting them at greater risk for delinquent behaviors, including substance use and abuse. In this study, social problems are a significant risk factor for drug use when moderated by high levels of cognitive distortions.

As with many human diseases and disorders, animal models are sometimes used to study addiction. For example, voluntary wheel running by rodents, viewed as a model of human voluntary exercise, has been used to study withdrawal symptoms, such as changes in blood pressure, when wheel access is removed from mice.

Another growing area is social media addiction. Psychology researchers surveyed 253 undergraduate students at the University of Albany and found that not only is social media (particularly Facebook) itself potentially addictive, those who use it may also be at greater risk for substance abuse.

The dependence potential of a drug varies from substance to substance, and from individual to individual. Dose, frequency, pharmacokinetics of a particular substance, route of administration, and time are critical factors for developing a drug dependence.

An article in "The Lancet" compared the harm and dependence liability of 20 drugs, using a scale from zero to three for physical dependence, psychological dependence, and pleasure to create a mean score for dependence. Selected results can be seen in the chart below.

According to a systematic review from 2014, prevalence rates of sexual addiction and related sexual disorders ranges from 3% to 6%.

Diagnostic criteria for compulsive buying have been proposed: 1. Over-preoccupation with buying; 2. distress or impairment as a result of the activity; 3. compulsive buying is not limited to hypomanic or manic episodes.

While initially triggered by a perhaps mild need to feel special, the failure of compulsive shopping to actually meet such needs may lead to a vicious cycle of escalation, with sufferers experiencing the highs and lows associated with other addictions. The 'high' of the purchasing may be followed by a sense of disappointment, and of guilt, precipitating a further cycle of impulse buying. With the now addicted person increasingly feeling negative emotions like anger and stress, they may attempt to self-medicate through further purchases, followed again by regret or depression once they return home - leading to an urge for yet another spree.

As debt grows, the compulsive shopping may become a more secretive act. At the point where bought goods are hidden or destroyed, because the person concerned feels so ashamed of their addiction, the price of the addiction in mental, financial and emotional terms becomes even higher.

ΔFosB, a gene transcription factor, has been identified as playing a critical role in the development of an addiction. Overexpression of ΔFosB in the nucleus accumbens is necessary and sufficient for many of the neural adaptations seen in drug addiction; it has been implicated in addictions to alcohol, cannabinoids, cocaine, nicotine, phenylcyclidine, and substituted amphetamines as well as addictions to natural rewards such as sex, exercise, and food. Moreover, reward cross-sensitization between amphetamine and sexual activity, a property in which exposure to one increases in the desire for both, has been shown to occur preclinically and clinically as a dopamine dysregulation syndrome; ΔFosB expression is required for this cross-sensitization effect, which intensifies with the level of ΔFosB expression.