Biting your nails, snoozing for an hour, or a glass of wine after dinner. Not all habits are good, and not all are bad. But when do we consider a habit good or bad? Let’s start with what a habit actually is, and then how we define a bad habit. In general, habits are repetitive behaviors that are learned by practice and turn into automatic behavior over time1–3. Think about brushing your teeth twice a day, walking the dog after school or work, or taking the same route to the train station every day. As habits are learned by practice and repetition, they are often associated with a specific context. Waking up could be linked to brushing your teeth, or your barking dog is associated with going for a walk after school. And the more we repeat an action, the stronger our habits become4,5. Did you ever forget to brush your teeth before going out in the morning? How weird (and gross) does that feel?! Habits can be quite handy (but not always), as habits are performed almost unconsciously, requiring barely any energy of your brain. The predictability and gratification of performing the habit, makes your brain’s life easy and predictable4. And our brains love predictability. That’s why it’s also so hard to break a habit or to learn a new one, our brains have to adapt and put effort in learning a new behavior, also called the “law of exercise”5. This means that the more often and consistent you are in learning a new habit, the stronger the habit behavior will be and the easier it will be to make it stick.
In our (sometimes) smart squishy brains, habits are driven by both our memory, or associative learning, and the dopamine pathways of our reward system. In our memory, there are two mechanisms at play regarding habits, namely stimulus-driven control and goal-directed control1,4. Together, they are often called the dual system. In a stimulus-driven control behavior, a specific trigger drives the behavior based on past experiences. For example, when you’re riding your bike back home from work, you always have to turn left on the last crossroad before your street. The stimulus here is the crossroad, which triggers you to behave in a certain way and go left. Goal-directed control behavior is quite different, where your behavior is driven by specific actions that will lead you to a goal or outcome. These two can often occur at the same time, and habits can even be changed if you focus more on the one compared to the other.
Diving deeper in the brain, habitual behavior is regulated by the dopaminergic system in the basal ganglia and striatum. Moreover, shifting from stimulus-driven to goal-directed behavior activates more areas and neurotransmitters in the brain, such as the release of glutamate, and endocannabinoid signaling in the orbitofrontal cortex (OFC)1,6. The OFC, which is the part that is basically ‘just’ lying above your eyebrows in terms of anatomy (image 1), is very important for executive function and inhibition control, as well as emotional regulation and is part of the reward system7.
Image 1. Brain areas involved in habits. Sourced and edited from4
Bad habits are, again, repetitive behaviors, but while they offer direct ‘gratification’ or satisfaction, they have long-term negative consequences. Some examples can be procrastination, overeating, or scrolling on your phone. The habits of biting your nails and that glass of wine at dinner are also not great for you. Overall, bad habits can be rather annoying, but they remain manageable. Since bad habits are so automated in your brain, and happen pretty much on an unconscious level, it can be quite hard to override. Usually, (bad) habits are also context specific, meaning that depending on the situation you’re in, your brain responds in a certain automatic way. For example, if you’re stressed or anxious, biting your nails or overeating can feel soothing for you, while it doesn’t have the greatest health effects. This can be super annoying, since we’re pretty aware of the fact that it’s not great for us! Although, I can speak from experience that nail-biting can be an absolute pain to get rid of, I can also confirm that my nails have been looking amazing for years now.
The point where bad habits become problematic is when they disturb your health and daily living. It may impact your sleep, your well-being, social life, and living circumstances. What often starts as casual or recreational use of drugs or alcohol, or goal-driven behavior (“getting high or drunk”), can later turn into stimulus-response behavior, becoming somewhat automatic with repeated use of the drug or alcohol8.
Based on the dual system theory, there can be an imbalance between the stimulus-driven and goal-directed system, which can result in quite extreme habitual behavior, such as obsessive compulsive disorders (OCD) and addiction. In the brain, these behaviors show different activation patterns in the areas mentioned earlier, such as the basal ganglia, OFC, and medial prefrontal cortex (mPFC). For example, a study showed that OCD patients showed less activation in the brain areas important in so-called inhibition control6. Less activity and connection means less control over the behavior. Another example of compulsive behavior is alcoholism, or alcohol use disorder (AUD). People with AUD will choose alcohol over healthier alternatives, despite the adverse consequences. Scientists often describe AUD more as a stimulus-driven instead of goal-directed control9. A specific context or situation as well as withdrawal symptoms such as feeling hungover can trigger the urge to drink again. Quick fix: repeat the cycle. The less goal-directed control you have, the bigger the risk is of relapsing.
In the case of drug abuse, we’ll take cocaine addiction as an example. The use of cocaine changes the structure of brain networks, specifically in the nucleus accumbens (NA; or ventral striatum) and dorsal striatum (image 1). These areas are associated with motivation, craving, and reward, and get input from the cortex8. When a person takes cocaine, it almost starts working instantly and dopamine levels immediately peak, but this doesn’t last that long and one would have to take it again to get the same satisfaction. And the cycle repeats. If we compare this to MDMA or amphetamine for example, their effects last way longer (not meant as a recommendation). Since the NA as a reward center plays such a large role in craving and reward, the motivation to get the same reward, so to use again, is big. If one would use cocaine over a longer period of time, we can see in the brain that the areas that get activated by prolonged use are growing, such as the NA or dorsal striatum. When increasingly more brain areas get involved in the habit of drug use, addiction and dependency is formed.
And now time for the good news: how to break bad habits (not addiction though), based on science4:
1.Weakening the stimulus-response links
In the approach of weakening stimulus-response links, the aim is to break the link and erase the association. Interestingly, studies show that erasing the stimulus doesn’t erase the association necessarily, but it connects the stimulus to a new response:A lack of response. In other words, when A happens, my brain learns that the new B has no effect, no response, and the motivation seems to ebb away. This actually seems to be a pretty effective method, and helps OCD patients and Tourette’s patients!
2. Avoid the habit stimulus
Next, as habits are pretty dependent on a specific context, situation, or stimulus, “simply” avoiding that context can help to avoid triggering a response. Not having any sweets or unhealthy food at home after you’ve done your groceries can be an example of avoiding a stimulus. Sometimes this can help, but in reality, we’re not always in a stimulus-free world (would be great some days though). When you get into a triggering situation again, chances are high that those sweets are inhaled by you in no time. Moreover, a context can also be internal, such as an emotional state. Maybe you eat your sweets when you’re stressed or super tired, and avoiding those types of contexts can be really complex and are often not ideal. Here, it could be helpful to question yourself why you’re feeling stressed or exhausted: are you busy at work, do you sleep well? Going back to the source and solving the problem here may help to avoid the stimulus that creates the (often negative) emotional state.
3. Goal directed inhibition
Goal-direction inhibition can be done in two ways: strengthening the goal-direction system (“I want to be and feel healthy”), and avoiding situations which weaken the system again (“I’ll take a different route home so I don’t pass the FEBO”). In exposure therapy, people are exposed to their triggers and are ‘trained’ to not behave as they used to. Tackling those intrusive thoughts and inhibiting them can very effectively help in changing behavior.
4. Competing stimulus-response associations (or substitute habits)
Competing stimulus-response control basically comes down to substituting your bad habits for new and good ones. This includes noticing the triggers, recognizing how your body responds, what the behavioral response is, and what to substitute it with. This way you also make it easier to stick to good habits, which is great to reinforce behavior and increase the likelihood of the good habit happening again. Together with a therapist, this strategy is the most successful for breaking bad habits!
On this Reddit page, there are even more ‘real-life’ ideas on how to break bad habits, focusing on the system, the actions, and mindset. If I would give you just one tip on breaking bad habits, be nice to yourself; you are often your own worst critic, and one mistake doesn’t make you a quitter, loser, or incapable of change.
Author: Lotte Smit
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