Long ago and far away, my girlfriend's dad and I went to help a friend whose wife had a lithium imbalance to get her out of the eastbound lanes of a major highway, where she was running around unclad at night. She really lost it when she got off her meds. It was a night to remember, but not something we spoke of in that relatively small community. Her husband stuck by her in spite of those occasional episodes, and imho, was a saint. That she had a lithium imbalance was known, and her doctors would get her sorted out, again. She was a kind, sweet, and wonderful lady when she wasn't having one of those episodes.
From:
https://www.ncbi.nlm.nih.gov/books/NBK499992/Effects of Lithium toxicity:
Physical
Neurologic Effects
Symptoms of intoxication include coarse tremor, hyperreflexia, nystagmus, and ataxia. Patients often show varying consciousness levels, ranging from mild confusion to delirium. Although the neurological symptoms are mostly reversible, some reports indicate that symptoms might persist for 12 months never resolve[9].
Renal Toxicity
Renal toxicity is more common in patients on chronic lithium treatment. Toxicity includes impaired urinary concentrating ability, nephrogenic diabetes insipidus (the most common cause of drug-induced NDI), sodium-losing nephritis, nephrotic syndrome along with other manifestations is prescribed[19].
Cardiovascular Effects
These are usually mild and non-specific. Almost all patients treated with lithium will develop T wave flattening. Sinus node dysfunction is the most common reported conduction defect followed by QT prolongation, intraventricular conduction defects, and U waves. These findings are reversible[20].
Gastrointestinal Effects
Symptoms typically occur within 1 hour of ingestion and are more common in the acute overdose setting [15].
Endocrine Effects
Lithium administration leads to the inhibition of thyroid hormone synthesis and subsequent release, resulting in hypothyroidism. Hyperthyroidism is less commonly manifested, which can mask symptoms of lithium toxicity and boost its toxicity by prompting cellular unresponsiveness and altered renal tubular handling of lithium [21].
While that may appear to be in the boonies, dust from the Sahara makes it, literally, around the world. There is no way there won't be folks somewhere downwind of that, and that does not include any battery disposal or recycling facilities, nor leachates therefrom getting into the water supply.
There are things in our everyday environment, commonly in trace amounts, and we function just fine with that, but when we concentrate them, there is such a thing as too much of a good thing.