Many people confuse the terms cross addiction and dual diagnosis.
They are separate concepts:
Cross addiction is a concept that implies that if a person has developed a severe substance use disorder (the term for addiction) to one substance, that person is at a higher risk to develop a substance use disorder to some other substance.
The notion of a dual diagnosis generally refers to an individual who has two very different and unrelated psychological disorders, such as depression and an alcohol use disorder.
Cross Addiction: Real or Myth?There is a body of information that is mostly based on anecdotal evidence that recovering individuals are in danger of developing substitute addictions to other substances. Thus, there are a lot of recommendations regarding individuals with past alcohol use disorders not being prescribed narcotic medications for pain control, individuals recovering from benzodiazepine disorders not drinking alcohol, etc. These types of case study evidence are useful in describing aspects of a broader and empirically validated theoretical concept, but they are the weakest forms of evidence to describe an overall theoretical concept.
The notion of an increase in the vulnerability to develop another form of substance use disorder following recovering from a different substance use disorder seems to have some relevance in terms of common sense reasoning. It is also consistent with many strict disease models of addiction where individuals are unable to make rational choices regarding substance use due to changes that occur in the brain. The notion that most forms of substance use disorders share some similar brain pathways, such as the reward pathway in the brain that is primarily mediated by the neurotransmitter dopamine, would reinforce the notion of a neurobiological substrate that is responsible for a vulnerability to developing a cross addiction. However, the actual empirical evidence for the notion of cross addiction was mixed until very recently.
- A 2004 study in the journal Addictive Behavior found evidence for grouping certain types of addictions together based on the function that the drug served. Individuals developing substance use disorders to one substance in the classification were believed to be in a higher risk to develop a substance use disorder to a similar substance within the same classification, consistent with the notion of cross addiction, although this second premise was not tested by this study. Only the basis for the notion that an increased vulnerability might reflect the similar properties of certain drugs was demonstrated to possibly have some validity.
- A 2008 study in the Journal of Addictive Diseases found that successful compliance with participation in a methadone maintenance treatment program for opioid use disorders was also significantly related to a reduction in alcohol and cocaine usage, a finding that goes against the notion of cross addiction.
- A 2010 study in the journal Drug and Alcohol Dependence reported that in a study of 28 daily marijuana users, those who also had a history of alcohol use disorders increased their alcohol consumption during periods of abstinence to marijuana, which was believed to be consistent with the drug substitution hypothesis that is related to the notion of cross addiction.
The notion of cross addiction is accepted as being very real in many circles; however, in other circles that point to empirical evidence, the notion of cross addiction is thought to be questionable.
A Recent Study Changes the Game
Despite the relative popularity of the notion of cross addiction in many addiction treatment program descriptions, and in many 12-Step groups such as Alcoholic Anonymous, there is actually very little empirical evidence to suggest that such a phenomenon exists. This lack of research was noted by a team of researchers at Columbia University Medical Center who performed an exhaustive study on the notion of cross addiction in over 34,000 adults as part of the National Epidemiological Study on Alcohol and Related Conditions (NESARC). The findings of their study were reported in the November 2014 edition of the Journal of American Medical Association – Psychiatry. The participants in the study were surveyed in 2001 and again in 2004. There were three questions/goals of the study:
- How many of the participants with a substance use disorder developed a new substance use disorder in the three-year period?
- How many individuals who developed a new substance use disorder had overcome or successfully treated their initial substance use disorder?
- What factors could help explain why some individuals with substance use disorders may be more likely to develop new substance use disorders later?
- People with active substance use disorders were about two times more likely to develop another substance use problem (27%) compared to individuals who substance use disorder was in remission (13%).
- Thus, individuals who were unable to address their original substance use issue were more vulnerable to developing other substance use issues than individuals who were successful in addressing their substance use disorder.
- However, a small number of individuals with a history of successful remission did develop a different substance use disorder.
- In statistical terms, individuals with a history of successfully addressing their substance use disorder were significantly less likely to develop another substance use disorder compared to individuals who were unable to address their substance use disorder in the time period covered by the study.
- The researchers concluded that evidence that individuals who recover from one substance use disorder are more vulnerable to developing a cross addiction in the future is not supported by the data.
The findings have some interesting implications regarding the notion of cross addiction:
In fact, the researchers concluded that the opposite of the notion of cross addiction was more likely – that individuals who have successfully negotiated treatment for a substance use disorder were less likely to develop another substance use disorder.
So Is Cross Addiction a Myth?
The researchers at Columbia University found that the highest risk group to develop a cross addiction after successful recovery from earlier substance use disorder were unmarried males, who had a relatively early onset of their substance use disorder, and had some type of comorbid psychiatric disorder, especially disorders that were marked by impulsivity.
There are some caveats to any research study, and this particular study has a number of particular strengths and potential weaknesses. The first weakness of this study is that the study only covered a three-year period. There is no way of knowing if other individuals developed or would develop a substance use disorder at a later time. Secondly, the data was self-reported data, which can sometimes be unreliable. Researchers in future should use objective measures of substance abuse in similar studies. Nonetheless, these weaknesses do not invalidate the findings. The study is one of the few studies that looks at the actual notion of the development of a cross addiction in individuals and is able to make solid conclusions based on real data.
In Cases of Cross Addiction, What Types of Drugs Increase Vulnerability?
There appears to be very limited data to answer this question aside from clinical observations. In general, it is often considered that substances that produce similar effects can result in a higher vulnerability to cross addiction. For example, drugs that might increase the risk of developing cross addiction would include:
Different drugs that have the effect of suppressing the central nervous system.
- Narcotic pain-relieving medications (Vicodin, OxyContin, etc.) and heroin
- Anti-anxiety drugs, such as benzodiazepines (e.g., Valium, Xanax) or barbiturates (e.g., Seconal)
- Sedatives and sleep aids
- Cannabis and other types of hallucinogenic drugs
Various types of stimulants including:
- Diet medications and over-the-counter diet aids that contain stimulants
- Ecstasy, MDMA, and similar derivative drugs
- Caffeine, although there is probably far less potential to become cross addicted using caffeine
- Other types of drugs that share similar effects, such as different types of hallucinogenic drugs (mescaline, Psilocybin) and different inhalants