substance addicts, concluding that addicted gamblers display more physical symptoms during withdrawal. Deficiencies in serotonin might also contribute to compulsive behavior, including a gambling addiction. There are three important points discovered after these antidepressant studies: Antidepressants can reduce pathological gambling when there is an effect on serotonergic reuptake inhibitors and 5-HT1/5-HT2 receptor antagonists. Pathological gambling, as part of obsessive-compulsive disorder, requires the higher doses of antidepressants as is usually required for depressive disorders. In cases where participants do not have or have minimal symptoms of anxiety or depression, antidepressants still have those effect. A limited study was presented at a conference in Berlin, suggesting opioid release differs in problem gamblers from the general population, but in a very different way from people with a substance use disorder. The findings in one review indicated the sensitization theory is responsible. Dopamine dysregulation syndrome has been observed in the aforementioned theory in people with regard to such activities as gambling. Some medical authors suggest that the biomedical model of problem gambling may be unhelpful because it focuses only on individuals. These authors point out that social factors may be a far more important determinant of gambling behavior than brain chemicals, and they suggest that a social model may be more useful in understanding the issue. For example, an apparent increase in problem gambling in the UK may be better understood as a consequence of changes in legislation which came into force in 2007 and enabled casinos, bookmakers, and online betting sites to advertise on TV and radio for the first time and which eased restrictions on the opening of betting shops and online gambling sites. Pathological gambling is similar to many other impulse-control disorders such as kleptomania. According to evidence from both community- and clinic-based studies, individuals who are pathological gamblers are highly likely to exhibit other psychiatric problems concurrently, including substance use disorders, mood and anxiety disorders, or personality disorders. Pathological gambling shows several similarities with substance use disorders. There is a partial overlap in diagnostic criteria; pathological gamblers are also likely to have a substance use disorder. The "telescoping phenomenon" reflects the rapid development from initial to problematic behavior in women compared with men. This phenomenon was initially described for alcoholism, but it has also been applied to pathological gambling. Also, biological data support a relationship between pathological gambling and substance use disorder. A comprehensive UK Gambling Commission study from 2018