Addiction research – Who are we studying?

I teach a class on the psychology of addiction (Psych 477 at California State University in Long Beach) and as I have been preparing the lectures something has become very clear to me – textbooks patently gloss over important details about the addiction research they cite. One of the most obvious gaps I’ve noticed this semester concerns the population of research subjects most addiction research is conducted on. An example will clarify:

A student group in my class had to read a study assessing the residual effects of methamphetamine on mood and sleep. They were amazed that no changes in mood were observed and that participants slept a full 6-8 hours the night after being administered meth! Would you have been surprised with these results given that we all have been told that crystal meth improves mood and causes insomnia?

Would it matter at all if I told you that the participants in the study were current meth abusers who use an average of 4 times every week?

For anyone not aware of the tainted history of health research in the U.S. (I’m including psychological research in this group), go ahead and read about the Tuskegee Syphilis Experiment and Stanford Prison Experiment (video here). There are other examples including Stanley Milgram‘s obedience studies, and more but as exciting as the discussion of these studies is, it’s time to get back to my main point.

It is mostly due to the ethically-questionable, psychologically damaging, research above that research institutions are now required to vet proposed research studies using Institutional Review Boards (IRBs) to assure that human participants in studies are consenting to participate of their own free will, are not coerced, and are not suffering undue damage. This is also true of addiction research. Rarely does the public consider this fact however when they are being reported on research relevant to addiction. I know this because the kids in my class never gave it a second thought.

When reading about addiction research, think about the subjects participating in itNearly all addiction research, especially studies utilizing “hard” drugs like cocaine, meth, opiates, etc., are required to make use of a very limited part of society – drug using individuals with a history of use of the specific drug of interest who are specifically not interested in treatment. Individuals who have never tried the drug or who want to be treated for drug abuse or dependence (addiction) are excluded due to ethical concerns. In most studies, participants can not qualify if they are addicted to drugs other than those being studies (except smoking, for which exceptions are usually made since we’d be able left with no participants otherwise) or have any associated mental health disorders, which are very common among addicted individuals. I would further assert that for at least a substantial portion of these research participants, the term “addicts” may not be appropriate since many addicts would not willingly give up using their favorite substance for a week or two to be replaces with a hospital bed and an experimenter controlled dose of drug or placebo. Taken together, our research subjects are pretty obviously not representative of all drug users, or all addicts, or all anything else. They make up a very specific group – less than perfect, but what we have to work with.

In some studies that attempt to make a direct comparison between controls (or drug naive participants) and drug users, this is likely less of an issue. This can happen when researchers try to examine brain structure differences, or performance on a specific psychological or physical test. In such cases researchers can at least statistically identify contributions of length of use, method of use, and other relevant data on differences between people who use and those that don’t. There are probably still some serious differences between “true” addicts, recreational users, and semi-chronic users that would be important to understand here, but we can’t so we don’t. But when it comes to assessing mood effects, or indeed any of a number of subjective effects of drugs, drug cravings, and withdrawal, this limitation in the population to be studied is something that often needs to be made explicitly clear to most public consumers of research. Since we can’t assess changes in mood, absorption rate, anxiety, or any other such measure (some exceptions for very low doses in very specific circumstances) among people who are new to the drug, we end up assessing them among people with a lot of experience, but not enough of a problem to want addiction treatment. Again, this should be considered a pretty specific type of drug user in my opinion.

There are other types of studies – those conducted with abstinent ex-users or addiction treatment intervention studies utilizing addicts who want, or who reported to, treatment on their own or in response to advertisements. While these studies make use of populations that can be considered at least closer to the individuals they are specifically aimed at – assessing the return of  cognitive function after short or long term abstinence or testing a new intervention on those who want treatment – they still bring on limitations that need to be specifically considered.

An important point – most researchers recognize these issues and make them explicitly part of their research publications, in a specific section called “Limitations” but what seems troubling is that the public doesn’t have any awareness of these issues. So when someone tells you that “they just found out meth doesn’t actually make people lose sleep,” take a second to ask “for who?”

Treating alcohol withdrawal with benzodiazepines – Safe if mindful

Alcohol withdrawal can lead to some pretty horrible side effects

Contributing co-author: Andrew Chen

Alcohol withdrawal can be extremely unpleasant (see here for an overview). Symptoms vary from person to person, but most people will experience some negative symptoms of alcohol withdrawal if they try to stop drinking after long term use.

Mild to moderate symptoms include headache, nausea, vomiting, insomnia, rapid heart rate, abnormal movements, anxiety, depression, and fatigue. Severe symptoms of alcohol withdrawal include hallucinations, fever, and convulsions (known as DT’s or delirium tremens). Most people undergoing alcohol detox do not require hospitalization, but in severe cases, hospitalization may be necessary (1). Since their introduction in the 1960s, benzodiazepines have been the drug of choice for treating severe cases of alcohol withdrawal.

Benzodiazepines, or benzos for short, are a class of psychoactive drugs that work to slow down the central nervous system by activating GABA receptors. This provides a variety of useful tranquilizing effects. Aside from relieving symptoms of alcohol withdrawal, benzodiazepines are also commonly prescribed to treat insomnia, muscle spasms, involuntary movement disorders, anxiety disorders, and convulsive disorders.

The most common regimen for treating alcohol withdrawal includes 3 days of long-acting benzodiazepines on a fixed schedule with additional medication available “as needed.” (2)

The two most commonly prescribed benzos are chlordiazepoxide and diazepam. Chlordiazepoxide (Librium) is preferred for its superior anticonvulsant capabilities while diazepam (Valium) is preferred for its safety against overdose with alcohol. Short-acting benzos like oxazepam and lorazepam are less frequently used for treating alcohol withdrawal (1).

Compared to other drugs, benzos are the safest and most effective method for treating difficult alcohol withdrawal. However, benzodiazepines do come with their own potential for dependence and abuse. Ironically, symptoms of benzodiazepine withdrawal are quite similar to those of alcohol withdrawal. Tapering off dosage is the best way to prevent serious withdrawal symptoms. To avoid such complications, benzodiazepines are only recommended for short-term treatment of alcohol withdrawal.

In short

Benzos can be very useful for helping long terms alcoholics deal with the difficult withdrawal symptoms that can accompany the detox period. Just be mindful so as not to find yourself right back where you started.

Citations:

1. Williams, D., McBride, A. (1998) The drug treatment of alcohol withdrawal symptoms: A systematic review. Alcohol & Alcoholism. 33(2), 103-115

2. Saitz, R., Friedmn, L. S., Mayo-Smith, M.F. (1996) Alcohol withdrawal: a nationwide survey of inpatient treatment practices. 10(9), 479-87

Rubber-band addiction recovery – No shame

There’s a specific issue that keeps coming up with nearly every addiction client I work with who is in early recovery. Regardless of whether they’re trying to stop unhealthy alcohol or drug use, sex or gambling behavior, or anything else, this issue keeps returning. It doesn’t even seem to matter if this is their first attempt at addiction recovery or if they’ve already been here many times before.

The issue: Shame about a desire to return to old behaviors and stopping their recovery.

At the Matrix Institute on Addiction where I see some clients, they call this “The Wall” suggesting that it usually comes right after a relatively easy period of recovery in which clients are self-assured and confident that they’ve got their addiction beat. “The Wall” is supposed to be marked by anhedonia, depression, severe cravings, irritability, and more fun stuff like that. After the wall is the promised land of long-term recovery. By identifying the specific stages of recovery addicts are supposed to gain more understanding of their process and experience less shame. I love the Matrix method, but I see things a little differently.  The way I see it, “The Wall” is far from a single point in time, but is instead part of a larger pattern I like to call Rubber-band Recovery.

Rubber-band Recovery in Addiction

Addiction recovery is similar to letting go of a stretched rubber bandI’m sure everyone reading this has at some point played with a rubber band, stretching it and letting it snap back to its original state or pulling it between two fingers and playing it like a string (another name for this approach could be String Recovery, but that might get confused with theoretical physics and we don’t want that). When pulling the rubber-band one way, its internal structure pulls back, trying to get back to its natural state. The body can be thought to do the same when placed under chronic alcohol and drug use in addiction – it has a slew of internal processes that work hard to keep the body in its natural state, at homeostasis. Naturally, due to the pharmacological mechanisms of alcohol, cocaine, methamphetamine, marijuana, and many other drugs, these systems usually fail at setting everything back to normal especially during the use itself, which is why we get high. However, their work in a body that consumes drugs on a regular basis is obvious – reductions in the production of specific chemicals (like relevant neurotransmitters), changes in the structure of the brain itself (like producing less receptors or even removing some from the brain’s cells), and production of chemicals that combat the drugs’ actions.

All in all, the body and brain of a long-time, chronic, heavy user of alcohol and drugs are different from the body and brain they started with in important ways that specifically relate to their alcohol and drug use. They are like the stretched rubber band, similar but obviously not the same as it was in its relaxed state.

Individuals in early recovery from addiction essentially experience what happens when that taut, stretched, rubber band is let loose. Hurrying up to get back to its natural state, to homeostasis, it releases all that pent up energy and rushes through its original state, overcompensating and stretching a bit in the other direction. For the addict in early recovery, this is the process of withdrawal. As we’ve spoken about numerous times before when discussing withdrawal, a brain that has reduced its own production of dopamine because of large amounts of methamphetamine that flood its dopamine reserves will still be left with very low dopamine when the crystal meth stops coming in. Low dopamine will bring about many effects that look exactly like the opposite of a methamphetamine high – a large appetite, low energy, and reduced movement and motivation. For heroin addicts, the drug that’s caused them to feel no pain and become constipated will cause their bodies severe pain, diarrhea, and trembling when it’s removed from the equation. Some withdrawal is actually life threatening due to the extreme changes in body chemistry and structure that happen after long term use. In addition to all of the direct effects of the drugs and alcohol, those internal processes that have been working hard to counteract the effects of the drugs (they’re called “opponent processes” by some addiction researcher like Dr. Christopher Evans from UCLA) are still turned up to 10 and are going to take a little time to get back to their original state as well. All in all, that leaves addicts feeling pretty crappy to say the least during withdrawal, the worst part of early recovery from addiction.

But like that good old rubber-band addiction recovery than quickly turns around. Having overcome the worst part of withdrawal, addicts in early recovery often experience joy, confidence, energy, and clarity they probably haven’t felt in a long time. That along with the environmental influence of loved ones who are extremely happy to see an addict quit (especially the first time around) give those in very early recovery a feeling of great well being and happiness, like a nice pink-cloud they get to ride on for a bit. Remember, the rubber band is moving back in the direction it came from during active addiction and it’s likely that brain processes are doing a little overcompensating the other way now too, turning down those opponent processes and flooding the brain with the chemicals it’s been missing.

But alas, this little turn doesn’t last too long and back we go into the darker place of negativity, low energy, anhedonia, and more. But instead of calling this stage “The Wall,” I understand it as one of the inevitable turns in what is sure to be a back and forth, seesaw like trip of recovery ups and downs. Periods of confidence in our ability to overcome our demons are followed by others that make us feel week and irritable. The good news is that just like with a rubber-band, each successive cycle on this seesaw gets a little less intense, which means that confidence, elation, depression, and anger turn into comfort, contentment, and ease – our new homeostasis. After a ride like that most addicts really need a little rest and when we reach this stage (no matter what it looks like specifically for each person), long-term recovery feels like the norm instead of an effort. This is the real end goal of recovery – a state of being that feels normal and that doesn’t involve unhealthy alcohol or drug use, sexual acting out, or gambling.

At the end of the rubber-band game we get back to just a good old unstretched rubber-band, and it feels good. In the process, it makes little sense to feel guilty, or ashamed, at all the intermediate stages. They’re part of the game of recovery and they’re essentially impossible to avoid completely. Intense cravings come during specific parts because of internal, biological, and external, environmental influences. Being ashamed of that would be essentially the same as being ashamed of extreme hunger when you haven’t eaten in 5 hours and see a commercial for your favorite food – silly and useless. I can guarantee that the rubber band doesn’t feel ashamed about they way it behaves when snapping back…

About Addiction: Addiction Recovery, Alcohol, and Drug Legalization

Yes, you’ve got it, it’s your 30 seconds of news about addiction from around the world (wide web). Enjoy the reading – you can claim you learned your “new thing of the day.”

Addiction recovery- Inpatient and Outpatient treatment plans

Addiction Recovery-Recovering from addiction is hard, no matter what type of addiction it is. In order to complete a successful recovery from addiction, a positive attitude helps. Holding a positive attitude increases the chances that the recovery attempt will be a successful one. We’ve written often about addiction treatment and tips to increase sucess.

Recovery Now– What are the stages to inpatient addiction treatment? According to Recovery Now, the stages of inpatient treatment include:  intake, detox, stabilization, and long term recovery. Though I don’t necessarily agree with every aspect of this article, it contains some good information about addiction treatment that every reader should know. This additional piece from Recovery Now discusses the appropriateness of inpatient versus outpatient addiction treatment for specific patients.

Alcohol use

Science Daily– We’ve talked about the link that has been found between family history of alcoholism and an individual’s obesity risk.  In this study a family history of alcoholism produced an increased risk for obesity, though the environment also played a large role in this link. Environmental factors include the types of foods that are eaten- foods that are typically high in calories from sugars, salt and fat.

Desert News– Everyone knows at least one person whose life has been affected by alcohol abuse in some form or another. Here is a story of how alcohol negatively affected a woman’s life and how it overtook her life ultimately leading to her death.

The Sydney Morning Herald– Drunk Driving is not just a problem in the United States, driving under the influence of alcohol appears to be a problem in other countries as well.  In Australia almost 1,400 people were arrested for alcohol-related offenses.

AOL Health-There is a multitude of information found on billboards and in TV commercials which explains the risks of drunk and drugged driving. Despite this information 30 million Americans are driving drunk each year and 10 million are driving while they are under the influence of drugs. This problem is very serious and is most problematic among drivers who are aged 16-25. Although there has been a drop in the overall number of individuals who are driving while they are under the influence, one in three car accidents still occur from drunk driving.

Drugs- The dangers of legal drugs, Marijuana, Adderall, and Methadone

Belfast TelegraphAlcohol and legal drugs are okay in small doses and can even be helpful in medical settings and for overall health. However it is important to note that there have been many more alcohol related deaths than deaths from illegal substances such as heroin and crystal meth. By far alcohol is the greatest perpetrator followed by prescription drugs including amphetamines, benzodiazepines and antidepressants. In Ireland in 2009 alone there were 283 alcohol-related deaths were registered in the north and 276 the previous year.

NIH News- There has been a recent increase in marijuana use among 8th graders according to NIDA’s monitoring the future survey. It was reported that the rate of eighth-graders who are using illicit drugs is 16 percent, a 2.5 increase from the previous year’s use of 14.5 percent. Among high school seniors cigarette use has declined but marijuana, ecstasy and prescription drug use has increased. Marijuana use among adolescents is so problematic because it affects the brains development as well as a person’s learning, judgment, and motor skills. Additionally 1 in 6 people who start using it as adolescents become addicted. The spike in the drug use may be attributed to the debate on legalization which may give a false impression that the drug has no negative effects or consequences.

‘WisconsinWatch.org– Use of Adderall, a medication for ADHD, is on the rise and in demand on many college campuses. Adderall is increasing in popularity and is easily accessible on college campuses because it helps individuals study.  The drug is particularly popular in the University of Wisconsin and many students are taking it despite the negative side effects it may bring. School officials are not educating the university population of the ill effects of Adderall so it continues to be used as a study aid. At least part of the worry has to do with the potential for such students to move on to even stronger versions of amphetamines such as crystal meth, so maybe the efforts should focus on teaching students about addiction to amphetamines and the associated risks.

Scotsman NewsMethadone a drug which is used to prevent withdrawal symptoms in individuals who were addicted to opiate drugs (and as a replacement medication in heroin addiction treatment) is going to be in high demand after nearly £2 million worth of the heroin was discovered on a raid in Scotland.  Police hope that by working with healthcare professionals they can help these drug users seek addiction treatment. Anyone who was effected by the drug raid are offered the support and care they need

Victimization and Drug Legalization

Physorg.com– A potential link has been found between victimization (and hence trauma) and the prevalence of substance use disorders. This was most evident for homosexual and bisexual men and women than it was for heterosexual men and women. Both gay men and women reported high prevalence rates of victimization some point in their lifetime with lesbian women twice as likely to report victimization experiences. Men and women who reported two or more victimization experiences were found to have higher odds of alcohol and other drug dependence.

London Evening Standard– Should drugs be legalized? That is the question that is popping up in many states across the United States.  Is marijuana safer if it is regulated by the state?  The argument for legalizing drugs goes a little something like this: Despite drugs being illegal there will always be a demand for them so if drugs are legalized then governments will be able to control drug quality before they are sold on the streets. Tax income from drug sales can then to educate individuals about drugs and to aid individuals who need addiction treatment

North West Evening Mail– Paul Brown, the director of Cumbria Alcohol and Drug Advisory Service spoke out after former drugs policy minister Bob Ainsworth and he called for the decriminalization of all banned substances. Brown informed attendees that only Portugal has decriminalized drugs and since that occurred crime rates have fallen and more individuals are willing to seek treatment for drug problems. Many substances that are legal such as alcohol and tobacco are bigger killers than drugs that are criminalized. Alcohol and tobacco kill an average 40,000 people a year this is 10 times more than any illegal drug.

About Addiction: Synthetic drugs, binge drinking, and recovery

You didn’t think we’d let you go a whole week without giving you another of our amazing updates about addiction news and research from around the globe did you? I’m sure you didn’t, and you were right! Here we are again with some good old discussions of marijuana, alcohol binge drinking, and other issues relevant to addiction and drug use. We hope you like it.

Synthetic Drugs and Marijuana

Greenbay Press Gazette– K2 is being sold and marketed as a legal substitute for marijuana and is also referred to as “Spice,” “Genie,” “Zohai” or simply “legal weed”. Apparently, cops in Wisconsin don’t like it too much and even though it hasn’t been banned in that state, they’re making trouble for those who sell it and store owners are complying by removing K2 products from their shelves.

Time– Another article examining the question “is marijuana addictive?” According the DSM, addiction is the compulsive use of a substance despite ongoing negative consequences, which may lead to tolerance or withdrawal symptoms when the substance is stopped. Although only about 10% of people who smoke marijuana become addicted to it by this definition, the real issue is how harmful the drug may be and what consequences it may produce for individuals who are using compulsively.

Science Daily– Speaking of negative impacts of marijuana use, this article discusses the possible neurobiological implications of marijuana and alcohol use during adolescence. Binge drinking in adolescence is a relatively common occurrence in many circles and it can detrimentally affect  cognitive functioning, especially in terms of attention and executive function.  Marijuana was found to, not surprisingly, leave adolescent users with impaired memory performance. The fact that this drug use is occurring during a sensitive developmental period likely doesn’t help.

ABC News– Kids aren’t the only ones who binge drink. Mothers who binge drink during pregnancy are increasing the chances that their babies will develop attention and memory deficits. It was estimated that about 40,000 infants are born each year with neurological and developmental damage that was caused by binge drinking. We’ve written about fetal alcohol syndrome in the past, and this piece touches on the same issues.

Addiction, recovery, and the good old drug trade

The Messenger– This article uses everyday language to explain the evolution of addiction and specifically seven signs that causal substance use is evolving into dependence. I can’t say I agree with everything said here, especially some of the statistics, but it’s a nice read, and as long as you recognize it for what it is – a very dumbed-down version of the real account of things – you’ll hopefully enjoy it!

Breaking the cycles– Sober Living Environments (SLEs)  is a term which is often spoken in  addiction/alcoholism treatment and recovery programs. Sober living houses provide recovering addicts with a drug-free environment in order to complete the transition from a residential treatment setting to stabilization and reintegration to a normal life.

Addiction Inbox– The UN has been monitoring designer drug trade. This report displays emerging trends in synthetic drug use. The drugs that are being observed are amphetamine-type stimulants, as well as designer drugs such as mephedrone, atypical synthetics like ketamine, synthetic opioids like fentanyl, and old standbys like LSD. The article gives a complete list of the findings of drugs used in a variety of countries and it is very fascinating.

Physical addiction or psychological addiction – Is there a real difference?

This is another one of the basic questions I get regarding addiction.

It seems that people think about physical addiction and psychological addiction as somehow separate processes. I think this distinction makes no sense. Even if people really meant what they were saying, the brain is undoubtedly part of the body, and therefore, psychological addictions are also physical.

The “Physical Addiction” Vs. “Psychological Addiction” truth

blackboardWhat people are really referring to when they make this comparison is the distinction between physical withdrawal symptoms and the addictive process in the brain. There’s no doubt that some substances, like alcohol, opiates, and the likes, leave long term users with horrible withdrawal symptoms that are terrible to watch, and even worse to go through. In fact, early addiction theories asserted that it was this horrible withdrawal syndrome that made people go back to drugs. This was called the Tolerance-withdrawal addiction theory.

The Tolerance-withdrawal addiction theory fell apart when addictions to substances that didn’t display such withdrawal effects became obvious (like cocaine addiction), and when getting people through the difficult withdrawal proved insufficient to cure their addiction (naltrexone was thought to be the magic cure once upon a time).

In one of my previous posts about marijuana addiction, a reader suggested that since marijuana does not produce horrible withdrawal symptoms, it can not be physically addictive. While withdrawal from marijuana, cocaine, methamphetamine, nicotine, and numerous other drugs does not result in the stereotypical “opiate-withdrawal-flu-like-syndrome,” there is no doubt that real withdrawal from these substances exists for long term users and it sucks: Fatigue, depression, anxiety, sleep disturbances, and trouble eating are only some of the symptoms that tend to show up.

Withdrawal – The real physical addiction

Withdrawal symptoms occur because the body is attempting to counteract the stoppage of drug ingestion. Just like tolerance builds as the body adjusts to chronic drug use, withdrawal occurs as the body reacts to its cessation.

As crystal meth increases the amount of dopamine present in the brain, the body reacts by producing less dopamine and getting rid of dopamine receptors. When a user stops putting meth in their body, the low production of dopamine must increase and additional receptors must be inserted. Like tolerance, the process of withdrawal, even past the initial, obvious, symptoms, is a long and complicated one. For crystal meth addicts, the initially low levels of dopamine result in what is known as anhedonia, or an almost complete lack of pleasure in anything. There’s no mystery as to why: Dopamine is one of the major “pleasure” neurotransmitters. No dopamine, no pleasure.

The process of addiction in the brain

So, if we’re going to try to dissect which drugs cause what effects on the body, it’s important that we understand the underlying causes for those effects and that we use the proper language. Withdrawal, tolerance, and addiction are different, though obviously related topics. Their interplay is key for understanding the addiction process, but their more subtle points can often be lost on those observing addicts unless they are well trained.

As I’d mentioned in earlier posts, our current best notions about addiction are that the process involves some obvious physical and psychological processes and some much more subtle effects on learning that are still being studied. A study I’m currently conducting is meant to test whether drugs interfere with some of the most basic learning processes that are meant to limit the amount of control that rewards have over behavior. Such fine distinctions are no doubt the result of the ways in which drugs alter the neurochemical reactions that take place in our brain. Such basic changes can not possibly be seen as any less important than physical withdrawal symptoms.

All in all, the only way to look at Addiction is as both a psychological addiction AND a physical addiction that are inextricably liked through our psyche’s presence in the brain, a physical part of the body. It may seem like a small thing, but this distinction makes many users feel as if their problem is less, or more, sever than that of other addicts. As far as I’m concerned, if you have a behavior that is making your life miserable and which you can’t seem to stop, it doesn’t matter if you’re throwing up during withdrawal or not. It’s an issue and you need help.

Addiction-brain effects – Tolerance, sensitization, and withdrawal

If you’ve been with us for any length of time, you’ve already read about the addiction-brain effects for specific drugs. I think it’s important to understand some of the more general changes that occur in the addicted brain regardless of the specific drugs used.

One of the most common effects of long term drug use is something called tolerance, or the reduced effect of a drug dose. A lot of people know about this one, especially if they’re users and have found themselves needing to use more and more to get the same effect. However, while this is the most known, it is not the only change in the body, or brain’s, response to drugs with repeated use. The other effect, known as sensitization, is characterized by the exact opposite reaction – an increase in the response to the drug.

Tolerance & Withdrawal in the addicted brain

toleranceThe exact mechanism by which tolerance occurs is different for each drug, but the overall concept is the same. With repeated drug administrations, the body adjusts its internal processes in an attempt to return to its initial level of functioning. Drug use normally causes greater quantities of neurotransmitters like dopamine, serotonin, the opioids, and adrenaline to be present in the drug user’s synapses (see here for a review). The body counters this by reducing its own release of these chemicals, reducing the numbers of receptors that can be activated by the neurotransmitters, and increasing functions known as “opponent processes” that are meant to counter their activity.

The interesting thing about tolerance is that by reducing the level of these important neurotransmitters, addicts are left with another, possibly more important effect, which is the loss of the addicted brain’s ability to respond to any reward, including natural ones like food, sex, enjoying a good football game, or anything else. Essentially, this sort of cross-tolerance leaves the addict less able to respond to rewards in general.

The reduced response to drugs, and the corresponding changes in the body and brain’s own functioning, have long been thought to be a major cause of addiction. The withdrawal that results once drug taking stops is closely linked to the development of tolerance. Still, we now know that tolerance and withdrawal are not necessary, and certainly not sufficient for the development of addiction. Nevertheless, they are referred to as the physical dependence portion of addiction and are often are part of the overall picture.

Sensitization

Sensitization is the term used for an increased response to the same dose of a drug. That might sound a little oxymoronic after the tolerance discussion we just had, but bare with me.

Tolerance commonly develops when drug use is constant, or ongoing. It’s an aspect of chronic, long-term, use. On the other hand, sensitization is likely to occur when a user engages in intermittent, binge-like, drug use happening either once daily, or with even greater spacing (as in once every few days) and in large quantities. When you combine chronic use with binge behavior, you can actually get both responses.

Sensitization to drugs has been shown for physiological responses like heart-rate, blood pressure, and movement in animals and humans. More importantly, sensitization plays a part in increasing the motivation for drug use. Just like sensitization increases the physical response to drugs, there is a corresponding increased response in the addicted brain in areas important for motivation (like the NAc and VTA for instance). If an addict responds more to their drug of choice after repeated use, it should come as no surprise that sensitization has also been hypothesized to play an important role in the addiction process.

Drugs cause brain changes that drive addiction

opponent processesWhen both tolerance and sensitization develop in someone who has been using drugs, they’re left with a reward system that is less responsive to rewards in general while being more responsive to the drugs they’ve been binging on and to cues (or triggers) that are associated with those drugs. If that sounds like a recipe for disaster, it is. If you’re an addict yourself, you don’t have to imagine this, you’ve lived it – A state where nothing seems rewarding without being high.

The problem is that both tolerance and sensitization are examples of changes in response to drugs that are completely outside of the control of the user. There’s no doubt that the average drug user doesn’t think about, or even recognize, that as they continue to use drugs, their body adjusts in multiple ways that can make it that much harder for them to stop use at a later point. It should be clear that this is not an issue for everyone – both tolerance and sensitization require repeated administration of drugs that are pretty close together. But they don’t require hundreds of uses, a few days with continuous, or intermittent use, are often enough to bring about these changes in the addicted brain.

We often hear that even the first hit of a drug can cause someone to be addicted. While there’s little doubt that even a single drug administration can change brain response in important ways, I can say with absolute certainty that using a drug repeatedly cause long-lasting changes in the brain chemistry that make future drug use more likely.