Excessive computer use may result in, or occur with:

- Lack of face to face social interaction

- Computer vision syndrome

Computer addiction can be described as the excessive or compulsive use of the computer which persists despite serious negative consequences for personal, social, or occupational function. Another clear conceptualization is made by Block, who stated that "Conceptually, the diagnosis is a compulsive-impulsive spectrum disorder that involves online and/or offline computer usage and consists of at least three subtypes: excessive gaming, sexual preoccupations, and e-mail/text messaging". While it was expected that this new type of addiction would find a place under the compulsive disorders in the DSM-5, the current edition of the "Diagnostic and Statistical Manual of Mental Disorders", it is still counted as an unofficial disorder. The concept of computer addiction is broadly divided into two types, namely offline computer addiction and online computer addiction. The term offline computer addiction is normally used when speaking about excessive gaming behavior, which can be practiced both offline and online. Online computer addiction, also known as Internet addiction, gets more attention in general from scientific research than offline computer addiction, mainly because most cases of computer addiction are related to the excessive use of the Internet.

Although addiction is usually used to describe dependence on substances, addiction can also be used to describe pathological Internet use. Experts on Internet addiction have described this syndrome as an individual being intensely working on the Internet, prolonged use of the Internet, uncontrollable use of the Internet, unable to use the Internet with efficient time, not being interested in the outside world, not spending time with people from the outside world, and an increase in their loneliness and dejection. However, simply working long hours on the computer does not necessarily mean someone is addicted.

Codependency does not refer to all caring behavior or feelings, but only those that are excessive to an unhealthy degree. One of the distinctions is that healthy empathy and caregiving is motivated by conscious choice; whereas for codependents, their actions are compulsive, and they usually aren't able to weigh in the consequences of them or their own needs that they're sacrificing. Some scholars and treatment providers feel that codependency is an overresponsibility and that overresponsibility needs to be understood as a positive impulse gone awry. Responsibility for relationships with others needs to coexist with responsibility to self.

Codependency has been referred to as the disease of a lost self. Codependent relationships are marked by intimacy problems, dependency, control (including caretaking) denial, dysfunctional communication and boundaries, and high reactivity. Often, there is imbalance, so one person is abusive or in control or supports or enables another person's addiction, poor mental health, immaturity, irresponsibility, or under-achievement. Some codependents often find themselves in relationships where their primary role is that of rescuer, supporter, and confidante. These helper types are often dependent on the other person's poor functioning to satisfy their own emotional needs. Many codependents place a lower priority on their own needs, while being excessively preoccupied with the needs of others. Codependency can occur in any type of relationship, including family, work, friendship, and also romantic, peer or community relationships.

Commonly cited symptoms of codependency are:

- intense and unstable interpersonal relationships

- inability to tolerate being alone, accompanied by frantic efforts to avoid being alone

- chronic feelings of boredom and emptiness

- subordinating one's own needs to those of the person with whom one is involved

- overwhelming desire for acceptance and affection

- perfectionism

- over-controlling

- external referencing

- dishonesty and denial

- manipulation

- lack of trust

- low self-worth.

Video game addiction (VGA) is 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.

In May 2013, the American Psychiatric Association (APA) proposed criteria for video game addiction in the 5th edition of the "Diagnostic and Statistical Manual of Mental Disorders", concluding that there was insufficient evidence to include it as an official mental disorder. However, proposed criteria for "Internet Gaming Disorder" were included in a section called "Conditions for Further Study".

While Internet gaming disorder is proposed as a disorder, it is still discussed how much this disorder is caused by the gaming activity itself, or whether it is to some extent an effect of other disorders. Contradictions in research examining video game addictiveness may reflect more general inconsistencies in video game research. For example, while some research has linked violent video games with increased aggressive behavior other research has failed to find evidence for such links.

Mobile phone overuse (mobile-phone addiction or problem mobile phone use) is a dependence syndrome seen among certain mobile phone users. Some mobile phone users exhibit problematic behaviors related to substance use disorders. These behaviors can include preoccupation with mobile communication, excessive money or time spent on mobile phones, use of mobile phones in socially or physically inappropriate situations such as driving an automobile. Increased use can also lead to increased time on mobile communication, adverse effects on relationships, and anxiety if separated from a mobile phone or sufficient signal.

Codependency is a type of dysfunctional helping relationship where one person supports or enables another person's drug addiction, alcoholism, gambling addiction, poor mental health, immaturity, irresponsibility, or under-achievement. Among the core characteristics of codependency, the most common theme is an excessive reliance on other people for approval and a sense of identity.

Given its grassroots origin, the precise definition of codependency varies based on the source but can be generally characterized as a subclinical and situational or episodic behavior similar to that of dependent personality disorder. In its broadest definition, a codependent is someone who cannot function from their innate self and whose thinking and behavior is instead organized around another person, or even a process, or substance. In this context, people who are addicted to a substance, like drugs, or a process, like gambling or sex, can also be considered codependent. In its most narrow definition, it requires one person to be physically or psychologically addicted, such as to heroin, and the second person to be psychologically dependent on that behavior. Some users of the codependency concept use the word as an alternative to using the concept of dysfunctional families, without statements that classify it as a disease.

Internet addiction disorder is not listed in the latest DSM manual (DSM-5, 2013), which is commonly used by psychiatrists. Gambling disorder is the only behavioural (non-substance related) addiction included in DSM-5. However Internet gaming disorder is listed in Section III, Conditions for Further Study, as a disorder requiring further study.

Jerald J. Block, M.D. has argued that Internet addiction should be included as a disorder in the DSM-5. However, Block observed that diagnosis was complicated because 86% of study subjects showing symptoms also exhibited other diagnosable mental health disorders.

Internet addiction disorder, more commonly called problematic Internet use (PIU), refers to excessive Internet use that interferes with daily life.

Shopping addiction is defined as the deficiency of impulse control which appears as the eagerness for constantly making new purchases of unnecessary or superfluous things. It is a concept similar to "compulsive buying disorder" and "oniomania", although these terms usually have a more clinical approach, related to a psychological individual disorder of impulse control. The phrase “shopping addiction” usually has a more psychosocial perspective . or it is placed among drug-free addictions like the addiction to gambling, Internet, or video-games.

Samuel Taylor Coleridge (21 October 1772–25 July 1834) was an English poet, critic, and philosopher who was, along with his friend William Wordsworth, one of the founders of the Romantic Movement in England and one of the Lake Poets. He wrote the poems "The Rime of the Ancient Mariner" and "Kubla Khan", as well as the prose "Biographia Literaria".

Coleridge was widely known to have been a regular user of opium as a relaxant, analgesic, antidepressant, and treatment for numerous health concerns. "Kubla Khan" was apparently written under the drug's influence, but the degree to which he used the drug as a creative enhancement is not clear. Although Coleridge largely kept his addiction as hidden as possible from those close to him, it became public knowledge with the 1822 publication of "Confessions of an English Opium Eater" by his close friend Thomas de Quincey. The "Confessions" painted a rather negative picture of Coleridge and his reputation suffered accordingly.

Where Coleridge first developed his opium habit is an issue of some scholarly dispute but it clearly dates from a fairly youthful period in his life. Coleridge’s own explanation is clearly laid out in a letter to Joseph Cottle;

However, most scholars agree that Coleridge had resorted to the use of Laudanum (the tincture form of opium) before this date, particularly during times of nervousness and stress. Because Laudanum was widely available and widely used as an analgesic as well as a general sedative, many people were given the drug for all sorts of medical and nervous complaints. Coleridge was probably given the drug numerous times in his youth during several bouts of rheumatic illness. Small medicinal dosages seldom lead to full-blown addiction but for Coleridge, who experienced the painful return of the symptoms many times in his life, it surely introduced him to the use of the drug much earlier than his story to Cottle admits.

Regardless of when and where Coleridge’s opium addiction began, it is clear that the more reliant on the drug he became, the more his work suffered, the less he was able to focus and concentrate, and the more strained his relations became. In fact, it is arguable that any analysis of Coleridge’s life must be done against the constant background of opium usage. But as important as the issue of opium is in Coleridge’s life, it is never a straightforward issue because he often hid it from public and familial view and at other times he exaggerated its importance to his work. In the 1816 publication of his major ‘opium’ poems Coleridge purposely drew a connection between his creative work and his opium usage. Desperate for some financial success with his poetry, Coleridge intentionally attempted to portray himself as a dreamy opium eater because he, perhaps rightly, believed that it would draw a morbid fascination to his work. Opium played an interesting role in the public image of Romantic literature. There was, for a long time, a kind of cult glamorization of the drug and a morose allure to stories of its usage for respectable members of the bourgeoisie who were titillated by such taboo subjects. It was with this in mind that Coleridge generated an image of himself as dreamy poet who created drug induced fantasies.

This dreamy image of himself began even before he was widely known to have been addicted to opium. In one of a series of biographical letters written to his friend Thomas Poole, Coleridge painted this picture of himself, a picture that would always endure. Coleridge writes:

This slothful image was one that endured even with some of Coleridge’s close friends and may have been consciously created by Coleridge in the earlier part of his career in order to draw attention away from his addiction. It was only later that Coleridge perceived an advantage to drawing attention not to himself as simply a slothful scholar but a dreamy opium eater.

The most popular story that connects Coleridge’s work with his opium usage was told by Coleridge in his well-known preface to the poem Kubla Khan. Coleridge wrote:

The sleep of this story is said by Coleridge to be a sleep of opium, and Kubla Khan may be read as an early poetic description of this drug experience. The fact that the poem is generally regarded as one of Coleridge's best is one of the reasons for the continuing interest and debate about the role that opium may have played in his creative output, and in Romanticism in general.

Coleridge, in his lucid moments, understood the problems with which he struggled better than most. In an 1814 letter to his friend John Morgan, Coleridge wrote about his difficulties.

In some respects, Coleridge's life bears a resemblance to that of a modern opiate addict. Unfortunately, as much as Coleridge had some grasp of his addictions and its results, as well as an unusually sharp sense of how this addiction might be treated, many of his closest friends and peers did not understand. The people who might have served him best, like Southey and Wordsworth, were far too willing to maintain his image as slothful and selfish; this despite the professional help that he constantly bestowed upon them. Men like Robert Southey, naturally conservative in outlook were not forward looking enough to comprehend the possibility of Coleridge’s addiction being a largely physical dependence, despite the fact that Coleridge himself, as well as a growing number of professionals like his friend Gillman, were aware of the physical aspect of drug reliance. On more than one occasion Coleridge pointed to the fact that physical restraint might eventually lead to a cure, and on several occasions under the treatment of Dr. Gillman, he was led thus to the edge of freedom from the drug on which he had formed such a dependence. Southey wrote from the position of moral indignation and explicitly denied the physical aspect of the drug issue. Southey wrote to Cottle:

Research by governments in Australia led to a universal definition for that country which appears to be the only research-based definition not to use diagnostic criteria: "Problem gambling is characterized by many difficulties in limiting money and/or time spent on gambling which leads to adverse consequences for the gambler, others, or for the community." The University of Maryland Medical Center defines pathological gambling as "being unable to resist impulses to gamble, which can lead to severe personal or social consequences".

Most other definitions of problem gambling can usually be simplified to any gambling that causes harm to the gambler or someone else in any way; however, these definitions are usually coupled with descriptions of the type of harm or the use of diagnostic criteria. The "DSM-V" has since reclassified pathological gambling as "gambling disorder" and has listed the disorder under substance-related and addictive disorders rather than impulse-control disorders. This is due to the symptomatology of the disorder resembling an addiction not dissimilar to that of substance-abuse. There are both environmental and genetic factors that can influence on gambler and cause some type of addiction. In order to be diagnosed, an individual must have at least four of the following symptoms in a 12-month period:

- Needs to gamble with increasing amounts of money in order to achieve the desired excitement

- Is restless or irritable when attempting to cut down or stop gambling

- Has made repeated unsuccessful efforts to control, cut back, or stop gambling

- Is often preoccupied with gambling (e.g., having persistent thoughts of reliving past gambling experiences, handicapping or planning the next venture, thinking of ways to get money with which to gamble)

- Often gambles when feeling distressed (e.g., helpless, guilty, anxious, depressed)

- After losing money gambling, often returns another day to get even ("chasing" one's losses)

- Lies to conceal the extent of involvement with gambling

- Has jeopardized or lost a significant relationship, job, education or career opportunity because of gambling

- Relies on others to provide money to relieve desperate financial situations caused by gambling

Experts describe the spectrum of behaviors designated as addictive in terms of five interrelated concepts: patterns, habits, compulsions, impulse control disorders, and physical addiction.

An addictive personality refers to a particular set of personality traits that make an individual predisposed to developing addictions. This hypothesis states that there may be common personality traits observable in people suffering from addiction. Alan R. Lang of Florida State University, author of an addiction study prepared for the United States National Academy of Sciences, said, "If we can better identify the personality factors, they can help us devise better treatment and can open up new strategies to intervene and break the patterns of addiction."

Since people buying more than they need is usual and accepted, even the most excessive behaviour takes a long time before being considered pathological. Shopping addiction generally manifests between 20–30 years old,

but is not usually detected until several years after, when the addiction has led the person to ruin and bankrupt.

There are usually two stages in coping with the problem. First, people around the addict or the health or social services detect the problem and try to treat it. When, because of the seriousness of the case, it is not possible to solve it in this way, specialised professionals, such as psychologist or psychiatrics, take part. The diagnosis and evaluation of shopping addiction is based on the analysis of confirmed behaviours and their consequences. Specific tests or questionnaires, as the FACC-II (Questionnaire on the psychological aspects of consumer addiction, debt and personal spending habits) are also used. These specific questionnaires or tests are useful in the diagnosis and evaluation of shopping addiction problems, and to drive the therapies in a proper way. FACC-II is one of the most specific and widest. The Edwards Scale is another approach which measures the tendency to compulsively buy. All these resources, as well as personal interviews of the addict and people who surround them, reports and other documents, enable knowledge of when people buy, what they buy and the methods of payment used.

Behavioral addiction is a form of addiction that involves a compulsion to engage in a rewarding non-drug-related behavior – sometimes called a natural reward – despite any negative consequences to the person's physical, mental, social or financial well-being. A gene transcription factor known as ΔFosB has been identified as a necessary common factor involved in both behavioral and drug addictions, which are associated with the same set of neural adaptations in the reward system.

The terms compulsive shopping, compulsive buying, and compulsive spending are often used interchangeably, but the behaviors they represent are in fact distinct. (Nataraajan and Goff 1992) One may buy without shopping, and certainly shop without buying: of compulsive shoppers, some 30% described the act of buying itself as providing a buzz, irrespective of the goods purchased.

CBD is frequently comorbid with mood, anxiety, substance abuse and eating disorders. People who score highly on compulsive buying scales tend to understand their feelings poorly and have low tolerance for unpleasant psychological states such as bad moods. Onset of CBD occurs in the late teens and early twenties and is generally chronic. CBD is similar to, but distinguished from, OCD hoarding and mania. Compulsive buying is not limited to people who spend beyond their means; it also includes people who spend an inordinate amount of time shopping or who chronically think about buying things but never purchase them. Promising treatments for CBD include medication such as selective serotonin reuptake inhibitors (SSRIs), and support groups such as Debtors Anonymous.

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.

Psychological dependence is a form of dependence that involves emotional–motivational withdrawal symptoms (e.g., a state of unease or dissatisfaction, a reduced capacity to experience pleasure, or anxiety) upon cessation of drug use or engagement in certain behaviors. Physical and psychological dependence are sometimes classified as a facet or component of addiction, such as in the DSM-IV-TR; however, some drugs which produce dependence syndromes do not produce addiction, and vice versa, in humans. Addiction and psychological dependence are both mediated through reinforcement, a form of operant conditioning, but are associated with different forms of reinforcement. Addiction is a compulsion for rewarding stimuli that is mediated through positive reinforcement. Psychological dependence, which is mediated through negative reinforcement, involves a desire to use a drug or perform a behavior to avoid the unpleasant withdrawal syndrome that results from cessation of exposure to it.

Psychological dependence develops through consistent and frequent exposure to a stimulus. Behaviors which can produce observable psychological withdrawal symptoms (i.e., cause psychological dependence) include physical exercise, shopping, sex and self-stimulation using pornography, and eating food with high sugar or fat content, among others. Behavioral therapy is typically employed to help individuals overcome psychological dependence upon drugs or maladaptive behaviors that produce psychological dependence.

Problem gambling (or ludomania, but usually referred to as "gambling addiction" or "compulsive gambling") is an urge to gamble continuously despite harmful negative consequences or a desire to stop. Problem gambling is often defined by whether harm is experienced by the gambler or others, rather than by the gambler's behaviour. Severe problem gambling may be diagnosed as clinical pathological gambling if the gambler meets certain criteria. Pathological gambling is a common disorder that is associated with both social and family costs.

The "DSM-5" has re-classified the condition as an addictive disorder, with sufferers exhibiting many similarities to those who have substance addictions.

The term "gambling addiction" has long been used in the recovery movement. Pathological gambling was long considered by the American Psychiatric Association to be an impulse control disorder rather than an addiction. However, data suggest a closer relationship between pathological gambling and substance use disorders than exists between PG and obsessive-compulsive disorder, largely because the behaviors in problem gambling and most primary substance use disorders ("i.e.", those not resulting from a desire to "self-medicate" for another condition such as depression) seek to activate the brain's reward mechanisms while the behaviors characterizing obsessive-compulsive disorder are prompted by overactive and misplaced signals from the brain's fear mechanisms.

Problem gambling is an addictive behavior with a high comorbidity with alcohol problems. Comorbidity is the presence of one or more diseases or disorders co-occurring with each other. A common feature shared by people who suffer from gambling addiction is impulsivity.

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.

Physical dependence on a substance is defined by the appearance of characteristic physical withdrawal symptoms when the substance is suddenly discontinued. Opiates, benzodiazepines, barbiturates, alcohol and nicotine induce physical dependence. On the other hand, some categories of substances share this property and are still not considered addictive: cortisone, beta blockers and most antidepressants are examples.

Some substances induce physical dependence or physiological tolerance - but not addiction — for example many laxatives, which are not psychoactive; nasal decongestants, which can cause rebound congestion if used for more than a few days in a row; and some antidepressants, most notably venlafaxine, paroxetine and sertraline, as they have quite short half-lives, so stopping them abruptly causes a more rapid change in the neurotransmitter balance in the brain than many other antidepressants. Many non-addictive prescription drugs should not be suddenly stopped, so a doctor should be consulted before abruptly discontinuing them.

The speed with which a given individual becomes addicted to various substances varies with the substance, the frequency of use, the means of ingestion, the intensity of pleasure or euphoria, and the individual's genetic and psychological susceptibility. Some people may exhibit alcoholic tendencies from the moment of first intoxication, while most people can drink socially without ever becoming addicted. Opioid dependent individuals have different responses to even low doses of opioids than the majority of people, although this may be due to a variety of other factors, as opioid use heavily stimulates pleasure-inducing neurotransmitters in the brain. Nonetheless, because of these variations, in addition to the adoption and twin studies that have been well replicated, much of the medical community is satisfied that addiction is in part genetically moderated. That is, one's genetic makeup may regulate how susceptible one is to a substance and how easily one may become attached to a pleasurable routine.

Eating disorders are complicated pathological mental illnesses and thus are not the same as addictions described in this article. Eating disorders, which some argue are not addictions at all, are driven by a multitude of factors, most of which are highly different from the factors behind addictions described in this article. It has been reported, however, that patients with eating disorders can successfully be treated with the same non-pharmacological protocols used in patients with chemical addiction disorders.

Gambling is another potentially addictive behavior with some biological overlap. Conversely gambling urges have emerged with the administration of Mirapex (pramipexole), a dopamine agonist.

The obsolete term physical addiction is deprecated, because of its connotations. In modern pain management with opioids physical dependence is nearly universal. High-quality, long-term studies are needed to better delineate the risks and benefits of chronic opiate use.

The DSM definition of addiction can be boiled down to compulsive use of a substance (or engagement in an activity) despite ongoing negative consequences. The medical community makes a distinction between physical dependence (characterized by symptoms of physical withdrawal symptoms, like tremors and sweating) and psychological dependence (emotional-motivational withdrawal symptoms). Physical dependence is simply needing a substance to function. Humans are all physically dependent upon oxygen, food and water. A drug can cause physical dependence and not psychological dependence (for example, some blood pressure medications, which can produce fatal withdrawal symptoms if not tapered) and some can cause psychological dependence without physical dependence (the withdrawal symptoms associated with cocaine are all psychological, there is no associated vomiting or diarrhea as there is with opiate withdrawal).

There are several different screening tools that have been validated for use with adolescents such as the CRAFFT and adults such as the CAGE.

Five indicators of exercise addiction are:

1. An increase in exercise that may be labeled as detrimental, or becomes harmful.

2. A desire to experience euphoria; exercise may be increased as tolerance of the euphoric state increases.

3. Not participating in physical activity will cause in one's daily life.

4. Severe withdrawal symptoms following exercise deprivation including anxiety, restlessness, depression, guilt, tension, discomfort, loss of appetite, sleeplessness, and headaches.

5. Exercising through trauma and despite physical injuries.

Key differences between healthy and addictive levels of exercise include the presence of withdrawal symptoms when exercise is stopped as well as the addictive properties exercise may have leading to a dependence on exercise.

Compulsions and addictions are intertwined and reward is one major distinction between an addiction and a compulsion (as it is experienced in obsessive-compulsive disorder). An addiction is, by definition, a form of compulsion, and both addictions and compulsions involve operant reinforcement; however, in addiction, the desire and motivation to use a substance or engage in a behavior arises because it is rewarding (i.e., the compulsions that occur in addiction develop through positive reinforcement). In contrast, someone who experiences a compulsion as part of obsessive-compulsive disorder may not perceive anything rewarding from acting on the compulsion. Often, it is a way of dealing with the obsessive part of the disorder, resulting in a feeling of relief (i.e., compulsions may also arise through negative reinforcement).

Deep brain stimulation to the nucleus accumbens, a region in the brain involved heavily in addiction and reinforcement learning, has proven to be an effective treatment of obsessive compulsive disorder.