We used to think that addiction results from the ingestion of addictive substances like alcohol or illegal drugs. The focus was on the effects of these substances on the human body and what changes they produced to render the user unable to control cravings and thus continuing consumption despite the negative consequences this behavior was having on their overall health and personal life.

The DSM-IV (Diagnostic and Statistical Manual of Mental Disorders – published in 1994) explains the process of addiction through the physiological effects of said substances and the impact of building tolerance.

At present, studies indicate a link between stress, particularly chronic stress and addiction. This might shed light on why not all people who consume these addictive substances such as alcohol become addicted and why others become addicted to food, internet, shopping, sex, their phones, etc. – this is called non-substance addiction.

The effects of stress on the individual also seem to influence substance choice. Someone who is experiencing high levels of anxiety caused by a highly competitive working environment will opt for a depressant like alcohol while those who have developed symptoms of depression will choose stimulants such as cocaine.

This shift in perspective is reflected in the DSM-V (2013). Through this article, we will try to give a concise account of the research we have so far on the link between stress and addiction.

What Is Stress?

How Stress Can Lead to Addiction

The term stress is used to refer to the perception and reaction to challenging, threatening and harmful stimuli. These stimuli can be in the form of interpersonal conflict, job loss, financial insecurity, illness or death in the family etc. – psychological stressors. Physiological stressors include exposure to extreme temperatures, sleep deprivation, food deprivation and hunger.

Whether psychological or physiological, the stressful stimuli are perceived by the brain as a threat and the “fight-or-flight” response is triggered. This involves the release of hormones like cortisol and adrenaline which are meant to help the individual response to the perceived threat. Studies show that dopamine is also released as a response to aversive stimuli, although this hormone is commonly associated with gratifying stimuli.

This is because stress has different levels. “Good” stress means stimuli that are perceived as mildly or moderately challenging for a short period of time. Then, this response, including the dopamine release, leads to better focus and motivation which is enjoyable because it induces a feeling of accomplishment, of increased competence and ability to surpass obstacles.

Short-term stress which is caused by uncomfortable events also raises the individual’s ability to focus. As a species, we have developed this mechanism to help us survive, but chronic stress places an “allostatic load” on our bodies which negatively impacts it’s ability to function at optimal levels.

Chronic stress is exposure to adverse stimuli over a prolonged period of time, especially coupled with unpredictability and the person’s perception that he or she cannot control the situation. It lowers the immune system, affects bone metabolism, decreases muscle mass, changes the way fat is processed and affects key regions of the brain.

Some of those regions are the amygdala (makes it more responsive, therefore chronic stress leads to increased sensitivity to stress like in a vicious cycle), hippocampus (prolonged stress response obstructs the hippocampus from receiving enough glucose resources thus damaging its structure which results in memory and cognitive impairment) and the prefrontal cortex which is responsible for decision making and impulse control – this means the individual becomes less able to control impulses and urges.

What Is Addiction?

Addiction is defined as a complex brain disorder in which the individual compulsively seeks to expose to the rewarding stimuli despite negative consequences. It changes the chemistry of the brain in similar ways chronic stress does and it’s associated with withdrawal symptoms – the body adapts, builds a tolerance to the stimuli and needs it to achieve homeostasis. Stopping exposure results in increased levels of distress and intense cravings.

The link between addiction to alcohol, drugs, gambling, sex, etc. and mental health issues such as anxiety, depression and PTSD has already been established. The individual uses these rewarding stimuli to mitigate their symptoms, they’re self-medicating.

Now let’s move on to the link between chronic stress and addiction.

The Link Between Stress and Addiction

This new research might explain how rehab centres mitigate the distress experienced through withdrawal symptoms through therapeutic techniques that mainly reduce the effects of stress.

Let’s go back to the dopaminergic response to stress. Stress increases dopamine release into the nucleus accumbens (NAc or NAcc) which has a significant role in motivation, aversion, and reward. Short term it serves to motivate the individual to resolve whatever issue is causing the “flight-or-fight” response. Long term it reduces the number of dopaminergic receptors leading to anhedonia – the inability to experience pleasure. Now the individual is no longer able to feel pleasure or reward from day to day activities, “the small pleasures in life”, and needs a dopamine “kick” to achieve it.

In the beginning, engaging in the addictive behavior offers temporary relief from the symptoms of chronic stress, but in the longer term, the person builds tolerance – meaning dopaminergic response further decreases and there’s an even lower number of receptors.

Depending on the type of drug ingested, it can cause further damage to the same regions of the brain that the chronic stress affected. The withdrawal symptoms make it even harder for a person with low impulse control to resist cravings.

This also provides insight into relapse rates: while the patients are receiving inpatient treatment, they’re away not just from triggers like events where alcohol is served, they’re also away from the stressful environment which might have led to developing the addiction in the first place. If they had a difficult job or strained relationship with their family, or they lived in a dangerous neighborhood, they go back to that and start to experience high levels of stress again.

Recognizing the role stress plays in the development of addictions advances treatment methods where greater emphasis is placed on teaching patients how to better manage symptoms of stress. At the same time, it shows the importance of channeling resources towards helping these individuals come out of stressful environments caused by socio-economic factors.