Prozac’s Effect On Neuroplasticity

Neuroplasticity is the brain’s ability to change over time, in accordance with our experiences, and what things we practise.

For example, before the ubiquity of GPS, taxi-drivers tended to get unusually well-developed in areas of the brain associated with memory and spatial reasoning. In contrast, your writer here, a person who does a lot of reading and writing and also uses at least 3+ languages daily, doubtlessly has overdeveloped language centers. A visual artist might develop much better visual centers. And so forth.

These changes are in large part physical, and very easy to measure (with the right equipment). It’s not hard to see when a certain part of the brain has proportionally more volume than usual, for example.

So, what does Prozac have to do with it?

More than a mood-brightener

Aside from the obvious primary intended effect of antidepressants (i.e., to treat depression by increasing relevant neurotransmitter levels), antidepressants have a bad reputation for side effects.

For example: How Serious Are Antidepressant Side Effects?

Some side effects are often exaggerated in popular (mis)understanding, such as: How Much Weight Gain Do Antidepressants Cause? ← the answer being: often less weight than people gain per year when not on antidepressants (although weight gain can happen, especially if one was previously under-eating while depressed)

When it comes to Prozac (the most well-known brand name for fluoxetine, a selective serotonin reuptake inhibitor (SSRI), which works by increasing serotonin levels in the brain by decreasing the rate at which the brain “loses” serotonin), it’s worth initially noting that while serotonin is mostly associated with happiness, it does other things too; see: Serotonin For More Than Just Happiness

The study we wrote about in that article found that it’s not just a matter of how much serotonin we have, but also where in the brain in accumulates, and which parts of the brain get prioritized. Sound familiar?

Recently, researchers (Dr. Ilida Suleymanova et al.) investigated the effects of serotonin on neuroplasticity, and found that indeed fluoxetine (Prozac) does more than boost serotonin—it also reshapes how certain brain cells manage energy and plasticity.

This happens as quickly as the first two weeks; for example, parvalbumin interneurons in the prefrontal cortex, which normally keep brain activity balanced, became less rigid after two weeks of treatment (which makes further changes much more possible), bearing in mind that since depression is linked to overly rigid brain circuits, this means that fluoxetine can “soften” these networks, allowing rewiring and flexibility.

• Specifically, mitochondria in these rigidity-inducing braincells got disempowered by reduced expression of energy-production genes (remember, people think of genes as unchangeable, but they can be turned on and off by hormones/neurotransmitters, amongst other things).
• Even more specifically, genes tied to adaptability were upregulated, and perineuronal nets that restrict plasticity were weakened.

To read this paper in full, see: Chronic treatment with fluoxetine regulates mitochondrial features and plasticity-associated transcriptomic pathways in parvalbumin-positive interneurons of prefrontal cortex

This becomes extra important as we age, because neurogenesis (the brain’s ability to produce new brain cells) is an important factor in neuroplasticity.

Contrary to popular belief, we continue to do this all the way through life, albeit it does usually slow down in older age, but there are things that affect how much this happens, and when.

To learn more about that, see: Building Your Brain At Every Age

Finally, if you’ve been considering antidepressants but haven’t been sure if they’d be right for you, then before you rush to your doctor to get a prescription for Prozac, you might want to check out: Antidepressants: Personalization Is Key! ← because it makes a difference which one you pick

Alternatively, if you don’t love the idea of having to keep taking something, you might consider: Psychedelics: Yes Even Once? ← since a single dose can have a lasting (positive!) effect on cognitive flexibility

Want to learn more?

You might like this book we reviewed a little while ago:

The Brain’s Way of Healing: Remarkable Discoveries and Recoveries from the Frontiers of Neuroplasticity – by Dr. Norman Doidge

Take care!