You know you should get things done. Start exercising, call the friend you haven’t talked to in a long time, or clean out the storage room. But it’s like the start button just isn’t working properly. However, researchers have found a possible, and somewhat unexpected, explanation for why motivation can sometimes disappear – even when the will is still there.
We often think of motivation as something mental, but recent years of research have shown that motivation is also influenced by what is actually happening biologically in the body.
One of these things involves how the immune system communicates with the brain. When the immune system is activated, various signaling molecules are released that help coordinate the defense against bacteria or viruses. And researchers have discovered that these signals can also affect the dopamine system – and thus how easy or difficult it feels to get started with things.
Dopamine is about more than just reward
Dopamine is often called the brain’s reward chemical, but that only describes part of its role. Dopamine also helps us take initiative, feel drive, and mobilize energy for things we want to do.
This is especially noticeable in the gap between appreciating a reward and actually being willing to make an effort for it. You can still know that a workout, a phone call, or a cleaned storage room would feel good. But still, that little extra that actually gets you to take the first step is missing.
This difference has become an important area of research when investigating how inflammation affects the brain.
Immune system signals reach the brain
Inflammation is a natural and important part of the immune system. It helps the body respond to infections, injuries, and other stresses so that the body can protect and rebuild itself.
But inflammatory processes can also occur more quietly over a longer period, without you noticing them.
When the immune system is activated, signaling molecules called cytokines are released. They help the immune system coordinate its work, but they can also affect how the brain’s neurotransmitters function.
In controlled studies where researchers temporarily activated the immune system in healthy people, they observed that activity in the brain’s reward system decreased. Participants also became less motivated to exert effort for a reward, even though they still appreciated it.
This suggests that inflammation, through signals to the brain, can affect the dopamine system in a way that changes drive rather than willpower.
The dopamine signal can become weaker
Research also shows that inflammatory signals can affect the dopamine system in several ways. Among other things, they can impair the brain’s ability to produce dopamine and affect how effectively the dopamine signal works between nerve cells.
The result can be that the dopamine system functions less efficiently, making it harder for the brain to create the drive that helps you get started.
A smart strategy – in the short term
In an acute infection, this is a smart strategy. The immune system needs a lot of energy to do its job, and it’s beneficial if the body can temporarily prioritize away from things that aren’t necessary.
Less desire to exercise, be social, or take on big projects can, in other words, be part of the body’s way of saving energy while it deals with invading viruses or bacteria.
The problem arises when inflammatory signals persist for a longer time. Besides chronic inflammation not being good for the body overall, it can also cause low motivation to persist. Even when there is no obvious illness you need to rest and recover from.
Low motivation can have many causes
One important thing to remember, however, is that low motivation can of course be due to many different things: stress, lack of sleep, depression, hormonal changes, nutritional deficiencies, or difficult life circumstances.
But lack of motivation caused by chronic inflammation can be a cause many are unaware of, since low-grade inflammation is not always easy to detect.
References
- Felger JC, Treadway MT. Inflammation Effects on Motivation and Motor Activity: Role of Dopamine. Neuropsychopharmacology, 2017.
- Dantzer R. Behavioral and Motivational Changes Induced by Cytokines. Novartis Foundation Symposium, 2002. (Alternatively his classic Cytokine-induced sickness behavior from the same period.)
- Eisenberger NI et al. Inflammation-Induced Anhedonia: Endotoxin Reduces Ventral Striatum Responses to Reward. Biological Psychiatry, 2010.
- Harrison NA et al. Inflammation Causes Mood Changes Through Alterations in Subgenual Cingulate Activity and Mesolimbic Connectivity. Molecular Psychiatry, 2015.
- Harrison NA et al. Effects of Inflammation on Hippocampus and Substantia Nigra Responses to Novelty in Healthy Human Participants. Molecular Psychiatry, 2015.
