Following a patient's report of a dramatic response to the addition of chromium supplementation to sertraline (Zoloft) therapy for dysthymic disorder, the authors initiated a series of single-blind and open-label trials of chromium picolinate or chromium polynicotinate in the treatment of dysthymic disorder that had failed to respond to antidepressant medication. In a series of five patients, chromium supplementation (200 mcg, once or twice a day) led to a remission of dysthymic symptoms in each case. Improvement was typically seen within several days to three weeks after the start of chromium therapy. Symptoms returned in each of the patients after single-blind substitution of chromium with other dietary supplements; symptoms again disappeared when chromium was supplementation resumed. Both chromium picolinate and chromium polynicotinate were effective. In some cases, treatment with chromium alone relieved symptoms; in other cases, the combination of sertraline and chromium was needed to control symptoms.

Comment: Dysthymic disorder is characterized by a depressed mood that does not fit the criteria for the diagnosis of major depressive disorder. Symptoms are present most of the day, and occur on more than 50% of days. When the patient is depressed, associated symptoms may include poor appetite or overeating; insomnia or excessive sleepiness, fatigue, low self-esteem, difficulty concentrating, and feelings of hopelessness. These symptoms overlap with what has variably been called reactive hypoglycemia, hypoglycemia, or dysinsulinism. Chromium is known to potentiate the action of insulin at the cellular level, thereby helping regulate blood-glucose levels. One study showed that chromium supplementation can prevent or minimize the fall in blood sugar levels that occurs in people with reactive hypoglycemia. Clinically, the symptoms associated with dysthymic disorder often respond to a blood-sugar-regulating diet. It is likely, therefore, that the improvements reported with chromium supplementation are due in large part to the effect of chromium on blood-glucose control. An effect on serotonin receptors, as described below, may also contribute to the beneficial effect of chromium.

McLeod MN, et al. Chromium potentiation of antidepressant pharmacotherapy for dysthymic disorder in 5 patients. J Clin Psychiatry 1999;60:237-240.