The Effects of Caffeine on Depression

Last updated August 28, 2024.
Edited and medically reviewed by Patrick Alban, DC. Written by Deane Alban.

Scientific evidence supports that caffeine can benefit depression, but it’s not right for everyone and all situations. Learn if caffeine can help you.

A major review of studies that included over 346,000 participants examined the link between caffeine and depression. 

Researchers concluded that caffeine, particularly in coffee, was protective against depression and that coffee worked better than tea, probably due to tea’s lower caffeine content.

" Caffeine should not be mixed with over 50 kinds of medications, including the most popular antidepressants.

When researchers in China performed a meta-analysis that included over 330,000 study participants, they also concluded that coffee and caffeine consumption were significantly associated with a decreased risk of depression. 

A large study of over 50,000 women found that those who consumed at least 2 to 4 cups of coffee per day were less likely to develop depression, compared to those who drank only one cup per week. 

Note that, since 80% of caffeine consumption is in the form of coffee, most studies used coffee as a source of caffeine. 

One Japanese study found the risk of depression to be inversely proportional to either green tea or coffee consumption. 

How Caffeine Alleviates Depression Symptoms

You’ll notice that all of the studies above involved lowering the risk of depression and did not address alleviating symptoms of depression.

So, you may be eager to know whether caffeine can help your mood right now.

Caffeine is a fascinating molecule that exerts a surprising number of influences on brain health and function.

No one, including the experts, knows for sure what causes depression.

Serotonin is the neurotransmitter most closely linked to depression.

This is why selective serotonin reuptake inhibitors (SSRIs), which are thought to work by increasing brain levels of serotonin, are the most commonly prescribed antidepressants. 

But these drugs only work for about 60% of those who try them, so clearly, low serotonin is not always the cause. 

Dopamine dysregulation can also be an underlying, but lesser-known, cause of depression. 

Dopamine is the neurotransmitter most closely associated with motivation, focus, and productivity. 

The symptoms of dopamine-based depression differ from those of serotonin-based depression.

Dopamine-based depression expresses itself as lethargy and lack of enjoyment of life, while serotonin-based depression tends to be accompanied by anxiety.

Coffee and Caffeine Are Anti-Inflammatory

There’s a promising theory that depression is not caused by neurotransmitter imbalances but as a result of chronic brain inflammation.

A little-known fact about the brain is that it has its own immune system.

Immune system messengers called cytokines can activate inflammation in the brain, destroying tissue and altering brain function. 

Who Should Not Use Caffeine for Depression

Just because many people benefit from caffeine doesn’t mean that it’s right for everyone.

There are a few demographic groups that should not use caffeine as a way to self-medicate their depression.

However, it’s been recognized since the late 1980s that caffeine may be counterproductive in these cases.

Taking schizophrenia patients off caffeine has been found to improve many of their symptoms. 

Depression and anxiety commonly occur together and there’s no doubt that caffeine exacerbates anxiety.

Caffeine consumption delivers a double whammy when you are under stress.

It causes stress hormones to skyrocket while simultaneously inhibiting GABA, the neurotransmitter of relaxation. 

If you have both depression and anxiety, as many people do, the benefits of caffeine for depression almost certainly do not outweigh the cost of increased anxiety.

2. Minimize Caffeine Intake If You Have Insomnia

Caffeine achieves many of its effects by blocking the activity of adenosine, a neurotransmitter that makes you tired and sleepy.

If you already have trouble sleeping, caffeine can make your insomnia worse which, in turn, can fuel your depression.

Caffeine-induced sleep disorder is so problematic that it’s a recognized psychiatric disorder. 

If you have problems sleeping and you still want to drink caffeinated drinks, drink them early in the day, at least six hours before bedtime. 

It can take as little as two, or as many as ten, hours after caffeine ingestion to metabolize half of it. 

You may find it worthwhile to figure out your ideal cut-off time and then stick with it.

Personally, I can’t consume caffeine after 2 pm and still expect to get a good night’s sleep.

Some SSRIs can significantly slow the breakdown of caffeine, increasing caffeine’s half-life tenfold from 5 to 56 hours, resulting in restlessness and anxiety. 

And when excessive amounts of caffeine are consumed, the combination of caffeine and SSRIs can cause seizures and serotonin syndrome, a potentially serious condition. 

A fourth kind of antidepressant, monoamine oxidase inhibitors, can boost the effects of caffeine and cause acute high blood pressure.

In her book Drug Mugger, pharmacist Suzy Cohen, RPh, reveals that the combination of caffeine and prescription antidepressants can trigger tremors and panic attacks.

Caffeine also affects other psychiatric medicines, including antipsychotic medications and lithium. 

Being pregnant or taking birth control pills doubles the usual half-life of caffeine, giving twice the jolt from any caffeine consumed. 

Additionally, caffeine is not good for an unborn child since it restricts growth, resulting in lower birth weights. 

5. Kids and Teens Should Not Use Caffeine for Depression

There’s some evidence that caffeine contributes to depression in young consumers.

Researchers have been able to detect measurable changes in the brain that occur when caffeine consumers go through withdrawal.

Using EEGs, they found that caffeine abstinence alters brainwave activity and increases blood flow to the brain. 

While increased blood flow to the brain is generally a good thing, this change induces caffeine withdrawal’s most common symptom, headaches.

In fact, 50% of those who cut back on caffeine experience headaches. 

Researchers have found clusters of other common caffeine withdrawal symptoms.

Fortunately, these symptoms are short-lived and usually reach their peak within 2 to 9 days. 

However, be forewarned that if you are seriously addicted to caffeine, it can take months to feel completely normal again.

During this adjustment period, it’s not uncommon to feel more tired and mentally foggy than usual.

Caffeine Dosage for Depression

Let’s look at what research has found about the ideal caffeine dosage for depression.

To Lower Your Risk of Depression

If your goal is to lower your risk of depression, the Nurses’ Health Study, which followed over 50,000 women for 10 years, can provide some guidelines. 

Drinking 2 to 3 cups per day reduced the risk of depression by 15% over the course of the study. 

Drinking 4 cups or more lowered the risk by 20%.

To Improve Your Mood

But if your goal is to use caffeine to improve your mood right now, the answer is not at all clear-cut.

So, you will have to determine your ideal caffeine dosage by trial and error.

If you currently don’t use caffeine, start with a low dose and gradually work your way up to larger amounts.

Notice how you respond.

The US Food and Drug Administration has set the upper safe limit of caffeine intake at 400 mg per day. 

At higher doses, caffeine becomes counterproductive by increasing anxiety and insomnia.

This is not a good trade-off, especially for people who have both depression and anxiety — a common occurrence. 

This chart provides a general idea of the amount of caffeine in popular caffeinated beverages.

The Best and Worst Sources of Caffeine to Treat Depression

While coffee is by far the most common source of caffeine in most Western countries, it’s not necessarily the best source for treating depression.

A better source may be green tea.