text: The adverse effects of lithium include:
  ;Very Common (> 10% incidence) adverse effects
  * Confusion
  * Constipation (usually transient, but can persist in some)
  * Decreased memory
  * Diarrhea (usually transient, but can persist in some)
  * Dry mouth
  * EKG changes — usually benign changes in T waves
  * Hand tremor (usually transient, but can persist in some) with an incidence of 27%. If severe, psychiatrist may lower lithium dosage, change lithium salt type or modify lithium preparation from long to short acting (despite lacking evidence for these procedures) or use pharmacological help
  * Headache
  * Hyperreflexia — overresponsive reflexes
  * Leukocytosis — elevated white blood cell count
  * Muscle weakness (usually transient, but can persist in some)
  * Myoclonus — muscle twitching
  * Nausea (usually transient)
  * Polydipsia — increased thirst
  * Polyuria — increased urination
  * Renal (kidney) toxicity which may lead to chronic kidney failure
  * Vomiting (usually transient, but can persist in some)
  * Vertigo
  * Weight gain
  ;Common (1–10%) adverse effects
  * Acne
  * Extrapyramidal side effects — movement-related problems such as muscle rigidity, parkinsonism, dystonia, etc.
  * Euthyroid goitre — i.e. the formation of a goitre despite normal thyroid functioning
  * Hypothyroidism — a deficiency of thyroid hormone.
  * Hair loss/hair thinning
  ;Unknown incidence
  * Sexual dysfunction
  * Hypoglycemia
  * Glycosuria
  Lithium carbonate can induce a 1–2 kg of weight gain.
  In addition to tremors, lithium treatment appears to be a risk factor for development of parkinsonism-like symptoms, although the causal mechanism remains unknown.
  Most side effects of lithium are dose-dependent. The lowest effective dose is used to limit the risk of side effects.