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

In November 2016, the American Association of Sexuality Educators, Counselors and Therapists (AASECT), the official body for sex and relationship therapy in the United States, issued a position statement on Sex Addiction which states that AASECT "does not find sufficient empirical evidence to support the classification of sex addiction or porn addiction as a mental health disorder, and does not find the sexual addiction training and treatment methods and educational pedagogies to be adequately informed by accurate human sexuality knowledge. Therefore, it is the position of AASECT that linking problems related to sexual urges, thoughts or behaviors to a porn/sexual addiction process cannot be advanced by AASECT as a standard of practice for sexuality education delivery, counseling or therapy."

In 2017, three new USA sexual health organizations found no support for the idea that sex or adult films were addictive in their position statement.

In November 16, 2017 the Association for the Treatment of Sexual Abusers (ATSA) published a position against sending sex offenders to sex addiction treatment facilities. Those centers argued that "illegal" behaviors were symptoms of sex addiction, which ATSA challenged they had no scientific evidence to support.

There is an ongoing debate in the medical community concerning the insufficient studies, and of those, their quality, or lack thereof, and the resulting analysis and conclusions drawn from them, such as they are. So far, without repeatable, meaningful, measurable, and quantifiable analysis, no medical community wide acceptably reasonable standards, a definition, have been drawn yet.

Hence, internet sex addiction, just like it's umbrella sexual addiction, is still not listed in the DSM-5, which is commonly used by psychiatrists in the United States for diagnosing patients problems in a standard uniform way.

Internet sex addiction, also known as cybersex addiction, has been proposed as a sexual addiction characterized by virtual Internet sexual activity that causes serious negative consequences to one's physical, mental, social, and/or financial well-being. It may also be considered a subset of the theorized Internet addiction disorder. Internet sex addiction manifests various behaviours: reading erotic stories; viewing, downloading or trading online pornography; online activity in adult fantasy chat rooms; cybersex relationships; masturbation while engaged in online activity that contributes to one's sexual arousal; the search for offline sexual partners and information about sexual activity.

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.

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

In the United States, the percentage of pathological gamblers was 0.6 percent, and the percentage of problem gamblers was 2.3 percent in 2008. Studies commissioned by the National Gambling Impact Study Commission Act has shown the prevalence rate ranges from 0.1 percent to 0.6 percent. Nevada has the highest percentage of pathological gambling; a 2002 report estimated 2.2 to 3.6 percent of Nevada residents over the age of 18 could be called problem gamblers. Also, 2.7 to 4.3 percent could be called probable pathological gamblers.

According to a 1997 meta-analysis by Harvard Medical School's division on addictions, 1.1 percent of the adult population of the United States and Canada could be called pathological gamblers. A 1996 study estimated 1.2 to 1.9 percent of adults in Canada were pathological. In Ontario, a 2006 report showed 2.6 percent of residents experienced "moderate gambling problems" and 0.8 percent had "severe gambling problems". In Quebec, an estimated 0.8 percent of the adult population were pathological gamblers in 2002. Although most who gamble do so without harm, approximately 6 million American adults are addicted to gambling.

Signs of a gambling problem include:

- Using income or savings to gamble while letting bills go unpaid

- Repeated, unsuccessful attempts to stop gambling

- Chasing losses

- Losing sleep over thoughts of gambling

- Arguing with friends or family about gambling behavior

- Feeling depressed or suicidal because of gambling losses

A conceptual model of PIU has been developed based on primary data collected from addiction researchers, psychologists, and health providers as well as older adolescents themselves. That study identified seven concepts, or clusters, that make up PIU using a concept mapping approach. These seven clusters are: psychosocial risk factors; physical impairment; emotional impairment; social and functional impairment; risky Internet use; impulsive Internet use; and Internet use dependence. The last three constructs have not been previously identified. Risky Internet use are behaviors that increase risks of adverse consequences. It is not just the amount of time spent on the Internet that puts an adolescent at risk; how the time is spent is also an important consideration. The impulsive use construct describes an inability to maintain balance or control of internet use in relation to everyday life. Finally, the dependent use construct reflects the more severe symptoms that are typically associated with addictions, such as withdrawal symptoms. Thus, internet addiction may represent a severe form of PIU.

Other research also stresses the fact that the Internet addiction disorder is not a unidimensional but a multidimensional construct. Various facets of Internet use must be differentiated because of their differential predictors, mechanisms and consequences. Online activities which, if done in person, would normally be considered troublesome, such as compulsive gambling, or shopping, are sometimes called "net compulsions".

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.

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.

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.

Specific genes predispose people to drug addiction—it's one of the behavioral disorders most strongly corrolated with genetic makeup—but environmental factors, especially trauma and mistreatment in childhood, also correlate strongly with addiction. . Examples such as physical or sexual abuse, and unpredictable expectations and behavior of parents, increase a person's risk for developing addiction.

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.

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.

Sensation-seeking has been studied as having a strong relationship with addictive personalities.

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.

Some medical systems, including those of at least 15 states of the United States, refer to an Addiction Severity Index to assess the severity of problems related to substance use. According to DARA Thailand, the index assesses potential problems in seven categories: medical, employment/support, alcohol, other drug use, legal, family/social, and psychiatric.

There are approximately 976 million smokers in the world. Estimates are that half of smokers (and one-third of former smokers) are dependent based on DSM criteria, regardless of age, gender or country of origin, but this could be higher if different definitions of dependence were used. Recent data suggest that, in the United States, the rates of daily smoking and the number of cigarettes smoked per day are declining, suggesting a reduction in population-wide dependence among current smokers. However, there are different groups of people who are more likely to smoke than the average population, such as those with low education or low socio-economic status and those with mental illness. There is also evidence that among smokers, some subgroups may be more dependent than other groups. Men smoke at higher rates than do women and score higher on dependence indices; however, women may be less likely to be successful in quitting, suggesting that women may be more dependent by that criterion. Higher nicotine dependence has also been linked with mental illness, including anxiety and depression.

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.

In order to maintain high-quality performance, some musicians take chemical substances. Some musicians take drugs or alcohol to deal with the stress of performing. As a group they have a higher rate of substance abuse. The most common chemical substance which is abused by pop musicians is cocaine, because of its neurological effects. Stimulants like cocaine increase alertness and cause feelings of euphoria, and can therefore make the performer feel as though they in some ways ‘own the stage’. One way in which substance abuse is harmful for a performer (musicians especially) is if the substance being abused is aspirated. The lungs are an important organ used by singers, and addiction to cigarettes may seriously harm the quality of their performance. Smoking causes harm to alveoli, which are responsible for absorbing oxygen.

Street children in many developing countries are a high risk group for substance misuse, in particular solvent abuse. Drawing on research in Kenya, Cottrell-Boyce argues that "drug use amongst street children is primarily functional – dulling the senses against the hardships of life on the street – but can also provide a link to the support structure of the ‘street family’ peer group as a potent symbol of shared experience."

A number of groups have been identified as being at greater risk of developing cannabis dependence and include adolescent populations, Aboriginal and Torres Strait Islanders (in Australia) and people suffering from mental health conditions.

Individuals with exercise addiction may put exercise above family and friends, work, injuries, and other social activities. If not identified and treated, an exercise addiction may lead to a significant decline in one's health.