Addiction-brain effects: Sex addiction, neurotransmitters, and being love addicted

***A disclaimer: Sex addiction is a relatively new concept in science. I haven’t been able to find much research on the subject, so much of what is being said here is my interpretation of the current literature on sexual responsivity in humans.***

sexI’ve already mentioned that scientists are beginning to consider behavioral addictions (like gambling and sex) as being similar to drug addiction. We’ve also covered sex addiction on the site quite a few times.

Since we’d covered the addiction-brain effects of some of the major drugs’ (see here for opiates, crystal meth, and cocaine), I thought it’s time to write about the possible science behind sex addiction.

The sexual activity cycle

Scientists have divided human sexual interaction into 4 stages:

  1. Desire – Represents a person’s current level of interest in sex. It is characterized by sexual fantasies and a desire to have sex.
  2. Arousal – Includes a subjective sense of sexual pleasure accompanied by a physiological response in the form of genital vasocongestion, leading to penile erection in men and vulva/clitoral engorgement and vaginal lubrication in women.
  3. Orgasm – Involves both central processes in the brain and extensive peripheral effects. Orgasm is experienced by the peaking of sexual pleasure, release of sexual tension, rhythmic contraction of the perineal muscles and pelvic reproductive organs, and cardiovascular and respiratory changes.
  4. Resolution – The final stage of the normal sexual response cycle. There is a sense of release of tension, well being, and return of the body to its resting state.

After sexSex addicts don’t seem to have a problem with stage 3, and resolution is more like the end of sexual behavior. So we will focus the rest of our attention on the other stages 1 and 2.

Sex and neurotransmitters

While sex doesn’t involve the ingestion of substances, each of the above cycles does involve the release of many of the neurotransmitters we’ve already discussed (dopamine, serotonin, etc.).

In fact, there seem to be three major area in the brain that are activated during sex:

  1. The Medial Preoptic Area (MPOA) – This is one of the areas where all the sensory inputs to the brain converge. This. This area is crucial for the initiation of sexual response – the move from desire to arousal. It is mostly the release of dopamine within this area that supports sexual responding. Animals with lesions here can’t  mount or thrust.
  2. Paravantricular  (male) or ventromedial hypothalamus – These area are responsible for non-contact sexual responses. Dopamine is once again the main activating agent here.
  3. The mesolimbic system – Important for the motivation towards anything “good” this system is also very involved in motivation for sex, a big part of the desire and arousal stages. As with drugs, it is the release of dopamine with this system that increases the motivation for sex.

We haven’t discussed the first two area much, and from my understanding, their functioning is relatively specific to sexual response. However, we’ve certainly mentioned the mesolimbic system. This is the same system involved in the brain’s processing of opiates, cocaine, methamphetamine, and essentially all other drugs. It is also the system in charge of food motivation.

As you can see, dopamine is an activating neurotransmitter for sexual response. Serotonin on the other hand, plays an inhibitory role in sex. Through its activity on a number of brain area, serotonin reduces desire, arousal, as well as the ability to orgasm. The increase of overall brain-serotonin levels is one of the main reasons for reduced sexual responsivity in individuals who are taking SSRI antidepressants.

What about sex addiction?!

Aside from a few specific authors (like P. Carnes), scientists still find themselves struggling with whether or not behavioral addictions should be considered similar to drug and alcohol addiction or whether they are examples of compulsive, or impulsive, behaviors. I personally believe that these all share more common features than we may yet realize.

Nevertheless, for addicts, the subjective experience of a substance, or behavioral, addiction is similar. It is an inability  to control a behavior in the face of repeated negative consequences that is often accompanied by a need for more and a reduced sensitivity to the act.

Given my recent reading on the brain processes involved in normal human sexual response, I’ve developed my own early theory about sex addiction:

Given that many of the same neurotransmitters are involved in the regulation of sex, it is my belief that sexual addicts or those experiencing sexual compulsions, fall into one of two categories that probably overlap to some extent:

  1. Individuals who have reduced inhibitory capacity (like those with impulse control disorder, ADD, or ADHD for example). These individuals find themselves acting out relatively impulsive behaviors that others without such dysfunction seem to effortlessly control. Given what we know about impulse control disorders, it is no wonder that these individuals often find themselves engaging in more than one such behavior, including drug, sex, and other poossibly addictive activities.
  2. Those who’ve had sex paired with a strong neurological response – Given the important role of dopamine in all rewarding activities (what scientists call appetitive response), it is very possible that two or more rewarding experiences that are linked may increase the brain’s response to any of the individual rewards.

neurons that fire togetherLet me explain the last point: In neuroscience, there’s the concept that Neurons that fire together wire together,” which is to say that events that happen at the same time, if they are strong enough, may form their own neural networks. If something strongly negative (like violence) happens in conjunction with sex, the experience might lower sex responsivity. However, if a strongly rewarding event happens at the same time, the link might serve to enhance response for both future sexual experiences and the linked event.  The people in the first group are likely to often fall into this category due to their use of psychoactive substances. Drugs release huge amounts of dopamine, which may then become linked with sexual response, making sex seeking as strong as drug seeking.

So that’s my take, for now, on sex addiction. Like other addictions, it has to do with the exposure to a very rewarding event that in a subset of individuals ends up developing an exaggerated response or an inability to control it. Since feeling of love and intimacy can often be just as rewarding, people often refer to themselves as love addicted, and not sex addicted.

Sources:

1) A. G., Resnick, & M. H. Ithman (2008). The Human Sexual Response Cycle: Psychotropic Side Effects and Treatment Strategies. Psychiatric Annals, 38, pp. 267-280.

2) E. M. Hull, D. S. Lorrain, J. Du, L. Matuszewich, L. A. Lumley, S. K. Putnam, J. Moses (1999) Hormone-neurotransmitter interactions in the control of sexual behavior. Behavioral Brain Research, 105, 105-116.

About addiction: Exercise, stigma, marijuana, and friendhip.

Here we are again. I’ve been slacking on this, but check out the new crop of great articles about addiction. As usual, if you press the title of this post, you’ll be rewarded with our relevant posts!!!

MSNBC: Exercise may help prevent substance abuse – Here’s an article that reports on some of the findings I’d recently talked about here.

Addiction Inbox: Treating addicts like human beings – About the stigma and shame associated with addiction.

Addiction tomorrow: Marijuana – a gateway drug?

Addiction recovery basic: Friendship in recovery – Having social support and friends is important, especially when trying to make huge changes in lifestyle like quitting an addiction.

Addiction brain effects : Opiate addiction – Heroin, oxycontin and more

Okay, we’ve talked about crystal meth and cocaine and how they affect the brain during drug use. As I mentioned, both cocaine and meth interfere with the way the brain stores and cleans up important neurotransmitters, including, most importantly, Dopamine and Norepinephrine.

opiates-morphine & heroinThe class of drugs known as opiates, which includes morphine, heroin, codeine, and all their derivatives (including oxycontin), acts on the brain in a completely different manner. Since our goal at All About Addiction is to explain drug use and abuse as comprehensively as possible, let’s turn our attention to this opiate addiction next.

Heroin, morphine, oxycontin, vicodin and other opiates

While cocaine and crystal meth work by disrupting the normal functioning of molecules responsible for cleaning up released neurotransmitters, opiates work by activating actual receptors that naturally occuring neurotransmitters activate. Substance like this are known as agonists; they perform the same action (identically as, to a lesser, or greater extent) as a substance the body already manufactures.

In the case of morphine, heroin, and most other opiates, the most important receptors activated are knownOpiate Receptors as µ-opioid receptors. Activation of the µ-opioid receptors is associated with analgesia (suppression of pain), sedation, and euphoria, which makes sense given the relaxing, pleasure inducing effects of opiates.

Natural opioids (also called endogenous opioids), which include endorphins, are used by the body to relieve pain and increase relaxation, especially during periods of extreme stress. These are the chemicals that make sure we can function during accidents, like after breaking our leg…

Opioids and dopamine

Opioids also increase the amount of dopamine in the brain indirectly. As I mentioned in the earlier posts, dopamine is thought to be the reward indicator in the brain. Unlike crystal meth and cocaine, heroin and its relatives increase the activity of dopamine neurons by releasing the hold that other neurons (that use GABA) have on them. Think of this as the release of pressure on a hose spraying water on a lawn. When the pipe is pinched, only so much water can get through, but once the clasp is released, water can flow in greater quantity; this is essentially what opiates do.

Heroin addiction and long term opiate use

Like I said before, this doesn’t sound so bad, does it? All we’re talking about here is the increasing of the functioning of system that already exists in the brain. The problem isn’t so much in the process, the problem starts when this system gets activated for long periods of time.

HeroinHeroin addicts, and other frequent users of opiates complain about the extreme discomfort they feel when they stop using the drugs. This discomfort has been described as the worse case of the flu you could imagine. Doesn’t sound too appealing, does it? In fact, withdrawal symptoms associated with stopping opiate use are at least one of the main reasons many users return to the drug after trying to clean up. This in addition to all the other effects of the drug on the brain to make wanting to stop so much harder.

The reason for the pains and aches? Given the overactivation of its pain suppression system, the body not only reduces its own supply of opioids, but it also turns up the sensitivity on its pain receptors. Heroin users notice this as an increase in tolerance, but they compensate for it by simply using more. However, when they stop, they’re left with a body unable to suppress its own, hyper sensitive pain system. The results are more than uncomfortable, they’re simply excruciating…

Another common complaint of addicts is diarrhea. This, again, is simply the reversal of the constipation caused earlier by heroin’s actions on opioid receptors that are present in the peripheral system (outside the central nervous system).

I’ve heard addicts speak online about the slow recovery from opiate addiction and I want to dispell a myth here:

Opiates DO NOT stay in your system for weeks or months – The drug itself is gone from the body within days. The reason for the continued suffering is the slow adjustment of your brain and body back to the way things were before the drugs. Think of how long the tolerance took to develop… Now play the tape back in reverse. That’s what happening to you. You can help relieve the pain, but know that if you use anything in the opiate family, you’re making the process last much longer…

So, in summary: As usual, the actions of opiates on the body and brain are not all the severe, extreme, or inappropriate. Opiates are still used in medicine for pain suppression, not only because they work, but because the potential for abuse when used in this way are minimal to non-existent. However, as with all drugs, continued, chronic, abusive use of opiates will change the way your body functions in ways that will produce the exact opposite effects of those users like so much. This leaves people not only with possible addiction problems, but also with a terrifyingly uncomfortable return back to normal functioning.

Addiction help

If you need help finding treatment for your own, or a loved one’s addiction, make sure to give our Rehab-Finder a try: It’s the only evidence-based, scientifically created, tool for finding rehab anywhere in the United States!

The brain addiction connection : Crystal meth, and our friend dopamine

We’ve talked about the general way in which neurons in the brain communicate with one another and then reviewed the ways in which cocaine messes some of the basic processes that the brain depends on.

It’s time to move on to another drug, and since the brain-addiction connection is similar for meth and cocaine, it seems the natural next step…

Methamphetamine (speed, ice, glass, crystal, meth)

Remember how we said that cocaine affects the way that dopamine is cleaned up after being released? Well, crystal meth also affects dopamine, but in a different way:

Instead of not allowing a molecule (DAT) to pull released dopamine back into the cell that released it, methamphetamine doesn’t allow the dopamine in a cell to be stored in the little packets that it’s supposed to be put away in. Like the DAT molecule, there’s another molecule that packages dopamine (and other neurotransmitters actually).

This molecule is called vesicular monoamine transporter (VMAT) because it puts a specific kind of neurotransmitter (called monoamines) into packets called vesicles.

You may be asking this right about now:

“If cocaine and crystal meth act in such similar way, why are their effects so different?”

That’s a very good question.

Even though these two ways of affecting dopamine seem very similar, they cause different changes in the levels of dopamine in the brain:

This flood is similar to the effect of crystal meth on the brain. By interrupting the way the brain packages dopamine, speed causes an unstoppable flood of this neurotransmitter.While cocaine doesn’t allow the neurons to take dopamine back up (reuptake), the brain has these small monitoring devices called autoreceptors. These receptors detect the levels of dopamine in the brain and adjust the output. When cocaine increases dopamine levels, these autoreceptors decrease the amount of dopamine being released.

The problem with crystal meth is that the dopamine can’t be packaged at all, which means that whether the autoreceptors tell the brain to turn down dopamine output, the fact that the dopamine won’t go into it’s packages means it just keep leaking out.

Imagine having a burst pipe and trying to stop the flood by turning down the faucet… not too helpful, right?!

So what you end up with is a long lasting flood of dopamine that the brain can’t do much about… You may have already figured it out, but this is one of the many reasons why crysal meth has become the new drug epidemic; it just does its job really really well!

Dopamine function in a non-drug-using, meth addict after quitting, and a meth addict after 1 year of staying cleanThe long lasting effects on the brain are similar to those of cocaine, but can be even more devestating. Meth is very neurotoxic meaning that at high levels, it can actually kill neurons by over exciting them. In fact, for both cocaine and methamphetamine, but especially for meth, it can take a very long time (a year or more) for dopamine function to look like anything close to a non-user’s brain (look for the decrease in red in the middle figure showing less overall activity in this area).

Check out this video about meth’s effects: