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I have ADHD.
I found that 800mg caffeine / day helps me stay alert and concentrated. I don't get jittery and I'm able to fall asleep normally.
I have read that Adderall and Ritalin sometimes do have those effects.
What's the difference between this and Adderall / Ritalin? Do all stimulants have the same effects?
I want to understand as much as I can about this before seeing my psychiatrist to make a decision.
800 mg/day is well above the maximum recommended amount (1)(3). High doses of caffeine (>600 mg/day) can increase the risk of spontaneous abortion in women (2). Caffeine directly affects the heart. Side effects related to this becomes especially pronounced at higher doses, and can cause tachycardia, and arrythmias (5).
Excessive caffeine consumption can result in severe psychological dependence and withdrawal (5).
Caffeine use is associated with increased risk of developing anxiety disorders (4).
Tolerance also develops with chronic caffeine consumption. Increased doses will be required to achieve the desired effects of enhanced concentration and reduction of fatigue (3).
Moderate amounts (100-200 mg/day) however, have been demonstrated to be safe (3).
There is some evidence to suggest that caffeine is an effective treatment for ADHD (5)(9). However, caffeine is not indicated for ADHD, and tolerance develops rapidly.
The drugs referenced interact with organisms in unique ways (i.e.: possess unique pharmacodynamics), and in turn, differ in their therapeutic effects, and side effects. The drugs also have varying pharmacokinetic profiles, meaning that they are absorbed, distributed, excreted, and metabolized differently in the body.
Caffeine is an antagonist at adenosine receptors 1 and 2A. This means it binds to said receptors without activating them. The presence of caffeine at the adenosine receptors prevents adenosine (an inhibitory neurotransmitter) from binding (and producing a response), thereby causing stimulation (1) . This activity also induces neurotransmitter release (2) .
From Mechanism of action (MOA) of Caffeine.
Additionally, caffeine is a more mild CNS stimulant than the amphetamines (i.e.: methylphenidate and amphetamine). The amphetamines are a more effective treatment for ADHD than caffeine (10)
Methylphenidate is a reuptake inhibitor of dopamine (DA), and to a lesser but still marked degree, noradrenaline (NE) (6). This activity increases the effect of these neurotransmitters, resulting in a reduction of symptoms.
Amphetamine is a releasing agent of DA, NE, serotonin (5-HT) (6).
Side effects such as anorexia, weight loss, and nausea tend to occur more commonly with amphetamine than methylphenidate. (8)
In regards to the therapeutic effect, there is no significant difference between methylphenidate and amphetamine overall (7).
