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The question is pretty simple — it's just a theory that I remember my biology teacher mentioned long ago and for years now I've wondered about it without ever asking.

Some people with attention deficit hyperactivity disorder (ADHD) report "energy bursts" with the feeling of needing to explode while sitting still. Further, they report that movement, like vibrating the legs, can help suppress this feeling.

Is there any reason to think that symptoms like these might come from too much ATP inside cells?

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That's an interesting hypothesis - however, I am not aware of any evidence that this is the case. Importantly, there can be a lot of difference between cellular access to energy, like ATP, and the perception of "energy" or liveliness.

Here is a paper that actually suggests the opposite: that ADHD could be caused by a neuronal energy deficiency because of differences in astrocyte responses to catecholamines (astrocytes are non-neuronal cells in the brain that, among other functions, regulate metabolism in the brain including access to glucose). Importantly, though, this remains just a hypothesis, not a well-established theory.

ADHD is thought to impact the parts of the brain that are important for attentional control, inhibiting responses, and motivation. Based on that perspective, an alternative explanation for the symptoms you describe is that a sensation occurs that doesn't really require a behavorial response, and for a neurotypical individual this sensation is quickly suppressed (attentional control by not focusing on this sensation, inhibiting your response to shake your leg) without any real conscious effort. Instead, with ADHD, it is difficult to direct focus away from that sensation and mental resources need to be directed towards trying to hold still. The relief from moving around comes from letting the activity progress and not trying to suppress it any more, not because there was a literal excess of energy in the sense of ATP.


References:

Barkley, R. A. (1997). Behavioral inhibition, sustained attention, and executive functions: constructing a unifying theory of ADHD. Psychological bulletin, 121(1), 65.

Todd, R. D., & Botteron, K. N. (2001). Is attention-deficit/hyperactivity disorder an energy deficiency syndrome?. Biological Psychiatry, 50(3), 151-158.

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I have no expertise in ADHD whatsoever, but basic biochemistry shows that this is not possible. A cell can't really have "too much ATP", and ATP does not by itself change how cells behave.

ATP is just a carrier of energy, an intermediate that stores energy extracted from nutrients like glucose and delivers it to energy-demanding processes like neurons firing action potentials ("work"). The amount of ATP stored in any cell is very small compared to the rate of production and consumption, so ATP is a short-lived molecule --- a cell's ATP store turns over (is consumed and renewed) in a few minutes. Therefore the amount of ATP does not really matter for energy metabolism; it is the rate of ATP production / consumption that matters.

Now, the rate of ATP metabolism is controlled by the demand for energy (how much work has to be done), not by how much nutrients are available. When cells need to do work --- for example, you start to run and muscles begin to contract --- the rate of ATP consumption increases. In response, the rate of ATP synthesis is increased by "burning" (oxidizing) nutrients more quickly, so that the system balances. Similarly, when a neuron starts to fire action potentials, its ATP consumption increases, and in response the cell generates more ATP by burning sugar. In contrast, ATP turnover cannot be increased by having too much nutrients. If this was true, cells would start doing work randomly as soon as they encounter nutrients, regardless of whether its needed or not, just to dispose of the generated ATP. Think about your legs starting to kick wildly as soon as you have a meal ...

In summary, the need to do work causes ATP turnover, not the other way around. Of course, having too little nutrients available does limit the amount of work that cells do, but that's a different question. Also, there are many signaling / hormonal mechanisms that alters behavior in response to nutrients. Eating a meal triggers reward centers in the brain, for example (hence, "comfort food"). But these systems are not directly related to ATP metabolism.

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