Severe depressive illness in the context of hypervitaminosis D

Hypercalcaemia, whether due to undiagnosed hyperparathyroidism or some other cause, can lead to clinical depression. The patient described here developed a severe depressive illness in the setting of hypervitaminosis D after 15 years of inappropriate therapy with calcium gluconate and strong calciferol. The importance of monitoring serum calcium levels in anyone on vitamin D therapy is stressed.