Clinical response and metabolic effects of lithium in 323 mood disorder patients

Background: Lithium is the mainstay for the maintenance treatment of mood disorders (MD), but its efficacy needs to be weighed against its side effects profile. Here, we assessed retrospectively the clinical response to long-term lithium treatment, as well as the rate of associated metabolic side effects. Methods: Clinical data were collected from patients treated with lithium for at least 12 months at the Lucio Bini Center for Mood Disorders in Cagliari, Italy. Clinical response was determined as the difference in number of mood episodes and percent of illness time before and during lithium treatment. Symptomatic values of metabolic parameters (plasma levels of glucose, cholesterol, urea nitrogen [BUN], creatinine, TSH, white blood cells [WBC]), and Body Mass Index (BMI) were determined. Results: We studied 323 MD patients (60.2% women). The percent of illness time was significantly reduced for both depressive (F = 4.94, p<0.0001), and manic (F = 3.95, p < 0.0001) episodes, whereas the rates of episodes/year were significantly reduced for mania (F = 2.01, p = 0.02), but not for depression (F = 1.54, p = 0.06). Rates of MD patients with symptomatic values of metabolic parameters were 14.3% for WBC ≥10,000/µl, 26.9% for glucose levels ≥100 mg/dl, 54.2% for cholesterol levels ≥200 mg/dl, 7.5% for BUN ≥50 mg/dl, 21.9% for creatinine levels ≥1.2 mg/dl, and 20.9% for TSH levels ≥3.50 mU/l. Conclusions: Long-term lithium treatment was clinically effective, but the rates of metabolic effects were substantial although some of them were also associated with older age. Lithium-treated patients should receive accurate clinical monitoring to decrease the impact of long-term side effects.