Correlation, causation, and association – What does it all mean???

July 28th, 2011

A comment posted by a reader on a post reprimanded me for suggesting that marijuana caused relationships to go bad.

In this instance the reader was mistaken, as I had specifically used the word “associated”, but the comment made me think that maybe I should explain the differences between correlation, causation, and association. I’m a scientist studying addiction, and in the field, it’s very important to be clear about what each of the words you use means.

Being clear about inferences in research

Correlation - When researchers find a correlation, which can also be called an association, what they are saying is that they found a relationship between two, or more, variables. For instance, in the case of the marijuana post, the researchers found an association between using marijuana as a teen, and having more troublesome relationships in mid, to late, twenties.

Correlations can be positive – so that as one variable (marijuana smoking) goes up, so does the other (relationship trouble); or they can be negative, which would mean that as one variable goes up (methamphetamine smoking) another goes down (grade point average).

The trouble is that, unless they are properly controlled for, there could be other variables affecting this relationship that the researchers don’t know about. For instance, education, gender, and mental health issues could be behind the marijuana-relationship association (these variables were all controlled for by the researchers in that study). Researchers have at their disposal a number of sophisticated statistical tools to control for these, ranging from the relatively simple (like multiple regression) to the highly complex and involved (multi-level modeling and structural equation modeling). These methods allow researchers to separate the effect of one variable from others, thereby leaving them more confident in making assertions about the true nature of the relationships they found. Still, even under the best analysis circumstances, correlation is not the same as causation.

Causation - When an article says that causation was found, this means that the researchers found that changes in one variable they measured directly caused changes in the other. An example would be research showing that jumping of a cliff directly causes great physical damage. In order to do this, researchers would need to assign people to jump off a cliff (versus lets say jumping off of a 12 inch ledge) and measure the amount of physical damage caused. When they find that jumping off the cliff causes more damage, they can assert causality. Good luck recruiting for that study!

Most of the research you read about indicates a correlation between variables, not causation. You can find the key words by carefully reading. If the article says something like “men were found to have,” or “women were more likely to,” they’re talking about associations, not causation.

Why the correlation-causation difference?

The reason is that in order to actually be able to claim causation, the researchers have to split the participants into different groups, and randomly assign some to the behavior or condition they want to study (like taking a new drug), while the rest receive something else. This is in fact what happens in clinical trials of medication because the FDA requires proof that the medication actually makes people better (more so than a placebo). It’s this random assignment to conditions (or randomization) that makes experiments suitable for the discovery of causality. Unlike in association studies, random assignment assures (if everything is designed correctly) that its the behavior being studied, and not some other random effect, that is causing the outcome.

Obviously, it is much more difficult to prove causation than it is to prove an association.

Should we just ignore associations?

No! Not at all!!! Not even close!!! Correlations are crucial for research and still need to be looked at and studied, especially in some areas of research like addiction.

The reason is simple – We can’t randomly give people drugs like methamphetamine as children and study their brain development to see how the stuff affects them, that would be unethical. So what we’re left with is a the study of what meth use (and use of other drugs) is associated with. It’s for this reason that researchers use special statistical methods to assess associations, making certain that they are also considering other things that may be interfering with their results.

In the case of the marijuana article, the researchers ruled out a number of other interfering variables known to affect relationships, like aggression, gender, education, closeness with other family members, etc. By doing so, they did their best to assure that the association found between marijuana and relationship status was real. Obviously other possibilities exist, but as more researchers assess this relationship in different ways, we’ll learn more about its true nature.

This is how research works.

It’s also how we found out that smoking causes cancer. Through endlessly repeated findings showing an association. That turned out pretty well, I think…

Posted in:  Education Tags: addiction, association, cancer, causation, correlation, FDA, marijuana, medication, meth, relationships, research, smoking, statistics

Higher drug abuse among gay youth likely tied to rejection

July 17th, 2011

For a lesbian, gay, or bisexual youth, “coming out” is an extremely stressful, though important event that can result in improved self-esteem, social-support, and psychological adjustment.

However, a recent study found that the reactions to such a disclosure have a lot to do with the risk of those youths abusing alcohol and drugs.

Social rejection and drug abuse among gay youth

The results revealed that the more rejecting reactions a youth receives, the more likely they are to engage in drug abuse including alcohol, cigarette, and marijuana use. This was true even after researchers controlled for a number of other important variables like emotional distress and demographics (race, ethnicity, education, socioeconomic status, etc.).

This makes a lot of sense. After finally deciding to go through with such a monumental disclosure, harsh rejections likely cause some serious damage to a youth’s self-esteem, making escape by drugs an attractive option. Although coming out can eventually lead to increased self-esteem even for this youth, the road there is not an easy one.

The good news was that accepting reactions seemed to protect youths from the harmful effects of being rejected – Social support helps!

The researchers suggested that drug abuse prevention attempts with LGBT youths address the impact of rejecting reactions to sexual-orientation disclosure directly in order to hopefully reduce their negative impact.

Here’s a video about the difficulties of coming out in high-school:

Reference:

Rosario, Schrimshaw, & Hunter (2009). Disclosure of sexual orientation and subsequent substance use and abuse among lesbian, gay, and bisexual youths: Critical role of disclosure reactions. Psychology of Addictive Behaviors, 23, 175-184.

Posted in:  Alcohol, Education, For others, Marijuana, Tips Tags: abuse, accepting, Alcohol, bisexual, coming, drug abuse, Drugs, gay, lesbian, marijuana, out, pot, rejection, self-esteem, smoking, support, transexual, weed

Talking to kids about teen smoking: The FTAS (Family Talk About Smoking) paradigm

June 17th, 2011

Newsflash: Kids don’t like being preached to – especially when it’s done hypocritically

A recent study assessed the impact parents have over the decisions their teenagers make concerning whether or not to ‘experiment’ with smoking cigarettes and to continue smoking in the long term, once they have tried it.

Experimenting with smoking represents a form of risk-taking for some teens while it can serve as the onset of long-term chronic cigarette smoking for others. Deciding which group a given teenager is a part of during the initial stage of experimentation is difficult, and figuring out whether it is possible to influence the trajectory of future behavior in teens is the focus of this line of research. The researchers theorized that variations in communication between parents and their teenagers might shine some light on these all-important issues.

So the researchers developed the Family Talk about Smoking paradigm, or FTAS, a method of standardizing the interaction and communication between teen smokers and their parents who had either smoked in the past or currently smoke. It’s a neat method that allowed them to study parent-teen interactions in a natural setting.

What is the FTAS – Assessing parent-teen communication

The FTAS is a 10-minute, semi-structured family interaction paradigm. It employs using a flip card the parent or teen are asked to read to one another. They take turns and each flip card initiates a conversation ‘trigger’ designed to stimulate smoking-related conversation. The cards focused on five triggers: a) “How people in our family feel about cigarette smoking,” (this is read by the teen), “My experiences with cigarette smoking” (by the parent), “How today’s teens make decisions about cigarette smoking,” (by the teen with this wording used to break open discussion without forcing teen to expose his own experience unless he wants to), and “What parent do if they find out their teen has become a smoker” (by the parent).

The families were given 10 minutes for each topic and were encouraged to use the entire time. Some families used the full ten minutes for some topics, and used less for others while other families sped through them all without lingering on specifics.

It may seem a little contrived and forced, but steps were taken to allow free-flowing conversations between parents and their teens. The FTAS discussion took place in the home environment in order to make the family more comfortable and there was a warm -up exercise to get everyone talking about their family life. When the time came for the FTAS discussion, the field staff left the room and observed the interaction remotely.

So, let’s look at what was measured.

A coding system was used to measure the:

• Level of disapproval the teenager received from the parent
• Just how clearly the parent elaborated on consequences for smoking cigarettes
• Whether the parent conveyed to the teen that he expected she would or wouldn’t be a smoker
• The quality of personal disclosure by the parent about his own smoking struggles or non-smoking

The teens and their parents were assessed initially and were then revisited 6 months after the baseline assessment to determine whether the family’s communication affected teen smoking 6 months later. It’s important to note: 90% of parents involved in the study had had some involvement with smoking at some point in their lives.

The patterns of communication between the teens involved in the study and their parent(s) varied depending on whether the teen (and his parent ) were smokers themselves. The teen’s receptivity to his parent’s attitude and communication about teenage smoking, and about his/her particular smoking, was directly affected by whether the parent smoked currently, or in the past, and what the parent’s attitude about it was as well as how openly the parent opened up to his teen about it.

While the study was a controlled assessment of teen-parent communication about smoking cigarettes, it’s important to note its implications for family communication about substance abuse, and other taboo issues. There’s no doubt that communication is extremely important when it comes to these topics and that open communication often leads to better outcomes than ignoring or avoiding these issues.

The results – Talking to teens about smoking can help if it’s done right

Communication patterns and their effect depended greatly on who the teen was speaking to – with mothers, expressing more positive expectancies about cigarette smoking predicted more persistent smoking while with fathers more disapproval during conversations predicted lower chances of persistent smoking.

The researchers found that non-smoking parents who had frequent and quality communication with their teenager about smoking had a consistently positive effect on reducing the chances that their teen will continue to smoke. However, the results revealed that if the parent smoked their influence through communication was much more complicated. For fathers, past smoking combined with a lot of teen disclosure predicted much greater likelihood of continued smoking – it’s the “war story” sort of effect with parent and teen sharing experiences and little disapproval leading to no reduction in experimentation. For currently smoking mothers the important factor was also disclosure but this time by the parent – if the mother shared little about her experiences, the effect on teen smoking was small but if she shared a lot, the odds of persistent teen smoking went way down. When non-smoking mothers talked a lot about the consequences of smoking, the probability of persistent teen smoking went up – kids don’t like being preached to.

What does it all mean?

Overall, the study’s results suggest that teens are highly suspect of hypocritical preaching and are very much influenced by communication patterns with their parents. Specifically, the study revealed that when a mother was a current smoker, if she communicated openly to her teenager that she had struggles about smoking and the difficulty of quitting, there was a positive effect on the teen’s eventual decision to stop. But for former smoking fathers and non-smoking mothers, talking at length about the teen’s experiences smoking and about the negative consequences of smoking respectively were not productive and actually increased the probability that the teen would still be smoking six months later.

As the authors note: “… current smoking mothers who are highly disclosing may acknowledge their own struggles around smoking and their difficulty asking their teens to “do what I say not what I do.” Openness about this struggle may help adolescents deal with the issue of “mixed messages” when a parent is a smoker. In contrast, the impact of maternal elaboration of rules may be attenuated when mothers have been active smokers because the parents’ own behavior is contradictory.” Reducing hypocritical messages and communicating openly about these difficult issues seems to be the way to go.

When taking all these findings into account it would seem that passivity on the part of a parent rather than communicating with the teen seems to be received by the teen as a silent approval of smoking. However a parent’s open and transparent sharing with his teen about his own regretted decisions, and the difficulty that has resulted, can have a very positive effect on the decisions the teen makes.

The bigger picture

If these things are true with cigarette smoking, would they not also be true regarding experimentation with other substances? Can parents open up about their experiences to their teens, expose their difficulties and vulnerabilities, and give the teen the gift of a loving parent’s experience?

Maybe more importantly, when thinking about the right ways to engage in teen-parent communication about difficult issues, a little insight into family dynamics that may have an impact on the discussion seems crucial. I often get questions from parents I know about the most appropriate way to talk to kids about drug use. This research seems to carry the following message – don’t preach if you haven’t been there and don’t be hypocritical if you have – open communication that guides the teen toward the desired behavior without letting them discount the impact of their choices seems the best idea.

Before we go, it’s important to note that this study used only a six-month follow-up and that future studies should really examine more long-term effects of family communication patterns in order to increase our confidence in these results. It’s possible that family communication can have a long-lasting effect or that it needs to be re-enforced on an ongoing basis. This study doesn’t tell us much about that.

Citation:

Lauren S. Wakschlag, Aaron Metzger, Anne Darfler, Joyce Ho, Robin Mermelstein, and Paul J. Rathouz (2010). The Family Talk About Smoking (FTAS) Paradigm: New Directions for Assessing Parent–Teen Communications About Smoking. Nicotine and Tobacco Research.

Posted in:  Education, Tobacco Tags: communication, family, parent, smoking, teen, teen parent communication, teen smoking

Global Commission on Drug Policy: Legalization, decriminalization, and the war on drugs

June 7th, 2011

A commission made up of some big names, though not really any names of addiction or drug researchers I noticed, just released a report that’s making a lot of noise throughout every news channel including NPR (see here, and here for stories) and others (see CNN). They want the debate about the current state of drug regulation expanded, and since I’ve written on the issue before, I figured it’s time for another stab at this. Read the rest of this entry »

Posted in:  Education, Opinions Tags: abstinence, Alcohol, cigarettes, CNN, commission, commission on drug policy, criminal, criminalization drugs, decriminalization, drug, drug use, Drugs, harm reduction, hope, legalization, NPR, offenders, prison, replacement medication, report, Richard Branson, should we legalize drugs?, smoking, stigmatization, stimga, syringe, treatment, War on Drugs

Convincing yourself to quit smoking – The influence of personal beliefs on smoking

June 5th, 2011

A study published in Addictive Behaviors showed that thinking actively about quitting smoking cigarettes allows people to smoke less!!!

In the experiment, participants from one group of smokers were asked to think about reasons to quit smoking and write them down on a piece of paper. Participants from a second group of smokers were asked to read pre-written anti-smoking arguments.

Both groups of participants were then asked to wait up to 30 minutes while the experimenter prepared a task unrelated to the actual experiment. Individuals who generated their own arguments against smoking abstained from smoking cigarettes longer than those who read pre-written anti-smoking arguments.

The results of this experiment suggest that self-generated information has a greater influence on smoking behavior (at least in the short-term) than information that is simply read.

Many anti-smoking campaigns try to “educate” people out of smoking cigarettes. They provide a great deal of information on the potential health hazards of smoking and try to convince smokers to quit. This approach can be dangerous as smokers might feel as though they are being attacked and react defensively. The truth is, many smokers already understand the consequences of tobacco use. If anti-smoking campaigns could find a way to develop personal beliefs against smoking, smokers might have an easier time not lighting up.

Citation:

Müller, B., van Baaren, R.B., Ritter, S.M. (2009) Tell me why…the influence of self-involvement on short term smoking behavior, Addictive Behaviors, 34(5)

Posted in:  Drugs, Education, Tips, Treatment Tags: abstain, addictive behaviors, anti, anti smoking arguments, anti smoking campaigns, anti-smoking, beliefs, cigarettes, feelings, group smokers, on smoking, quit smoking, quitting, smokers, smoking, smoking cigarettes

ADHD and neurocognition – Knowing what to remember

February 22nd, 2011

Kate Humphreys

ADHD In children and adults – Symptoms and tests

Children with attention deficit hyperactivity disorder (ADHD, formerly known also as ADD) are classically seen as the kids in class who have trouble staying in their seats and paying attention during long lessons. Underlying these problematic behaviors is a confluence of factors, with evidence pointing to genetics, neural function, and environmental factors (including parenting and lead exposure) that can all affect ADHD behavior. Many children diagnosed with ADHD seem to simply “grow out” of their symptoms. They may learn particularly effective strategies for managing inattention and disorganization (I myself am a notorious list maker), or learn to control some of the fidgeting and restlessness or channel that energy into sports or other activities. Read the rest of this entry »

Posted in:  Education Tags: ADD, ADHD, attention deficit hyperactivity, attention deficit hyperactivity disorder, children, children adhd, high value, high value wrods, hyperactivity, hyperactivity disorder adhd, impulsivity, inattention, marijuana, memory, memory capacity, nicotine, planning, smoking, substance abuse, value, value words, words

Tobacco smoking alone isn’t enough: More than smoking important in lung cancer death

January 11th, 2011

Christopher Russell and Adi Jaffe

The tobacco epidemic already kills 5.4 million people a year from lung cancer, heart disease and other illnesses. By 2030, the death toll will exceed eight million a year. Unless urgent action is taken tobacco could kill one billion people during this century. (The World Health Organization Report on the Global Tobacco Epidemic, 2008)

These are some scary numbers, right? Cigarette smoking, according to the WHO, is the single most preventable cause of death in the world today, and in conveying these deadly statistics to the general public, cigarettes have come to be alternatively referred to by smokers and non-smokers as “cancer sticks”, “nicotine bullets”, and “coffin nails”.

But does smoking really ‘kill’ anybody in the literal sense with which we use this word?  To an epidemiologist, tobacco smoking (nor many other drugs of abuse for that matter) does not “kill” a person or “cause” illness or death in the way the words “kill” and “cause” are typically understood by the media and general public. For example, if I shoot someone in the head, stab another in the heart, and strangle a third till he stops breathing, it is reasonable to say that my actions were the direct, sole, and sufficient causes of death – I would have killed them. Smoking, however, is often neither a sole nor sufficient ‘cause’ of lung cancer, coronary heart disease, or myocardial infarction because non-smokers die from these diseases, and for example, because only 1 in 10 heavy smokers die from lung cancer when one looks at the overall numbers. Read the rest of this entry »

Posted in:  Drugs, Education, prevention, Tobacco, Treatment Tags: biological heredity, cancer, cancer sticks, death, died lung cancer, dying lung cancer, genetic, heart disease, heredity, high, high heredity, high risk, low biological heredity, lung, lung cancer, lung cancer death, nicotine, risk, risk factor, risk factors, smokers high heredity, smoking, tobacco, who