In case you didn’t guess, the clues are in the brain. Our unique brain — its structure, functionalities, and chemistry — explain why some people exhibit promiscuous behavior despite being in happy, romantic relationships or why some people become addicted to the bottle despite not having an alcoholic member in the family.

Scientists have long believed that the environment has a role to play in triggering risky sexual behavior and problem drinking tendencies. But they now know that certain unique structural features of the brain can predict if an individual will abuse alcohol or show promiscuous behavior in reaction to stress.

Addictive tendencies triggered by stress

Early-life stresses, such as being raised in an abusive household, can alter brain chemistry and functionality and may trigger substance use and abuse tendencies.

These neural changes also increase the likelihood of addiction relapses and motivate an individual who has been exposed to drugs to seek the addictive substance in reaction to stress. These tendencies create a vicious circle because the chronic drug use further alters the stress-reward pathways in the brain making the individual more vulnerable to lapse into drug-seeking behavior during stress.

The relation between stress and problem drinking has been highlighted in a number of studies. For example, it was shown that women who experience economic hardship, stressful life events, and live in inhospitable situations are more prone to alcohol addiction than women who are not exposed to these stressors.

However, none of these studies have pinpointed the exact brain regions that are involved in triggering stress-related addictive tendencies. And certainly none of these studies have indicated that there also exists a reverse cause-effect pathway: peculiarities in brain structure can trigger stress-related drinking behavior.

Stress-related problem drinking and promiscuity: the culprits in the brain

An interesting experiment was carried out on a group of young adults with an average age of 19 years. Non-invasive fMRI images of their brain activity showed that an overactive ventral striatum and an underactive amygdala tend to trigger problem drinking in individuals who are undergoing stress.

The ventral striatum is linked to reward-seeking behavior while the amygdala is involved in processing threats from the environment. So having an overactive ventral striatum predisposes an individual to impulsive behavior because he is forever in search of thrills and goodies.

On the other hand, an underactive amygdala cannot adequately assess threats present in the environment or figure out their implications. The combination of an overactive ventral striatum and an underactive amygdala makes a person more likely to succumb to the “charms” of alcohol without realizing the dangers of his behavior.

During the course of this study, scientists also discovered that subjects with an underactive ventral striatum but an overactive amygdala also tended to exhibit problem drinking tendencies as a reaction to stress. An underactive ventral striatum is associated with feeling the blues and depression while an overactive amygdala makes an individual perceive threats even when there is none and be more sensitive to stress. It is likely that these individuals take to alcohol in an attempt to cope with the stress.

From an earlier study, scientists know that the reason why people react differently to sexual cues can be found in their brains. Scientists also know that these responses can predict who will later exhibit promiscuous behavior. But this study did not identify the regions of the brain that are involved in these tendencies. However, they are now more enlightened.

In a recently published article, researchers revealed that individuals with an overactive ventral striatum and an underactive amygdala are also more prone to promiscuous behavior. These findings corroborate what scientists had unearthed in an earlier study: sex addicts tend to report impulsivity and higher rates of sexual arousal to cues when they are stressed-out than during any other state.

From the findings of these studies, researchers believe that imbalance in the activities of these two areas of the brain is at the root of promiscuous and problem drinking behaviors. Individuals who show high or low levels of activities in both these areas are usually not prone to maladaptive drinking and sexual behaviors.

The role of the decision-maker: the prefrontal cortex

The ventral striatum, over- or underperforming, sends some signals. The amygdala too, produces some signals. So who moderates and makes the final decision? The prefrontal cortex.

Scientists are now curious to know what role the prefrontal cortex plays in pushing a person towards drinks and sex versus motivating him to speak to a counselor or sweat it out at the gym in response to stressors. Scientists were encouraged to look into the role of the prefrontal cortex after several studies implicated this region of the brain in the development of addictive tendencies in response to stress.

According to one study, children who were subject to early childhood abuse and went on to exhibit disruptive social behavior tend to show alterations in the orbitofrontal cortex region.

Another study found that subjects with damage to the ventromedial prefrontal cortex region are more likely to regard personal moral violations as acceptable when confronted with dilemmas. So these individuals are more likely to behave in socially unacceptable ways when making a choice is difficult and stressful.

Learning about the markers that can predict problem drinking and promiscuous behavior in individuals in reaction to stress presents a significant breakthrough with regard to the treatment and rehabilitation approaches currently in practice now. With this new-found knowledge, scientists, psychiatrists, and neurologists can identify individuals who are at risk and devise therapeutic methods that will help them behave in more socially acceptable ways. This knowledge should also help counselors, therapists, and psychologists find ways to guide their patients to alter their reactions to stress.

References

Bancroft, J., & Vukadinovic, Z. (2012). Sexual addiction, sexual compulsivity, sexual impulsivity, or what? Toward a theoretical model The Journal of Sex Research, 41 (3), 225-234 DOI: 10.1080/00224490409552230

Ciaramelli, E., Muccioli, M., Ladavas, E., & di Pellegrino, G. (2007). Selective deficit in personal moral judgment following damage to ventromedial prefrontal cortex Social Cognitive and Affective Neuroscience, 2 (2), 84-92 DOI: 10.1093/scan/nsm001

Demos, K., Heatherton, T., & Kelley, W. (2012). Individual Differences in Nucleus Accumbens Activity to Food and Sexual Images Predict Weight Gain and Sexual Behavior Journal of Neuroscience, 32 (16), 5549-5552 DOI: 10.1523/JNEUROSCI.5958-11.2012

Hanson, J., Chung, M., Avants, B., Shirtcliff, E., Gee, J., Davidson, R., & Pollak, S. (2010). Early Stress Is Associated with Alterations in the Orbitofrontal Cortex: A Tensor-Based Morphometry Investigation of Brain Structure and Behavioral Risk Journal of Neuroscience, 30 (22), 7466-7472 DOI: 10.1523/JNEUROSCI.0859-10.2010

Mulia, N., Schmidt, L., Bond, J., Jacobs, L., & Korcha, R. (2008). Stress, social support and problem drinking among women in poverty Addiction, 103 (8), 1283-1293 DOI: 10.1111/j.1360-0443.2008.02234.x

Nikolova, Y., Knodt, A., Radtke, S., & Hariri, A. (2015). Divergent responses of the amygdala and ventral striatum predict stress-related problem drinking in young adults: possible differential markers of affective and impulsive pathways of risk for alcohol use disorder Molecular Psychiatry DOI: 10.1038/mp.2015.85

Sinha, R. (2008). Chronic Stress, Drug Use, and Vulnerability to Addiction Annals of the New York Academy of Sciences, 1141 (1), 105-130 DOI: 10.1196/annals.1441.030

Victor, E., Sansosti, A., Bowman, H., & Hariri, A. (2015). Differential Patterns of Amygdala and Ventral Striatum Activation Predict Gender-Specific Changes in Sexual Risk Behavior Journal of Neuroscience, 35 (23), 8896-8900 DOI: 10.1523/JNEUROSCI.0737-15.2015

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