Caffeine poisoning can manifest as mental and/or physical symptoms mimicking various conditions ranging from depression to psychosis and from slight muscle stiffness to multiple sclerosis.

The mechanism is based on caffeine's potentation of various neurotransmitters according to individual genetic properties. Adrenaline accelerates the sodium exchange pumps of resting skeletal muscle cells and the intracellular sodium level rises. Sodium binds extracellular water in the cell until it bursts, letting out myoglobin, which causes levels of porphyrins rise in blood and apply toxic stress to brain cells. The process can take years before manifesting any symptoms, as they are hidden under the pharmacodynamical effects of caffeine.

First symptoms can be peripheral neuropathy in the form of muscle stiffness in neck and shoulder region. This is accompanied with paresthesia in scalp, face, upper extremities and expands to other parts of the body and limbs on individual timeline. GAD, panic disorder and depression start at the same time or after the physical symptoms.

I suggest, that caffeine poisoning is actually a rhabdomyolysis based form of acquired porphyria.

The condition can be tested and treated. Blood, 24hr urine and feces should be examined for myoglobin, protoporphyrins and coproporphyrins. If the first tests are unclear or negative, myoglobin and porphyrins stored in the broken cells can be chelated with a suitable sulphur-based chelator like DMSA, MSM or plain garlic from the grocery store. New tests can be made in 3-5 days after introducing the chelating agent.

Amounts of porphyrins may be so high, that some form of blood filtration may be needed in worst cases or if the chelating process advances too fast. Porphyrins are known to cause kidney failure and liver cancer. Filtration may be needed in worst cases or if the chelating process advances too fast. Porphyrins are known to cause kidney failure and liver cancer.

It is possible, that active caffeine metabolites can have accumulated in the body, this should be considered in context with the chelating process, and blood filtration.