Dysgeusia Successfully Treated With Sertraline

A 78-year-old man, who had never experienced depressive symptoms, suddenly noticed peculiar dysgeusia. He described every food as having no taste but was able to discern sweet, salty, sour and bitter tastes. He lost weight because of appetite loss and was referred to the otorhinolaryngologist in our hospital. Serum concentration of zinc was low but the administration of zinc sulfate failed to improve dysgeusia. His dysgeusia persisted for 6 months and was thereafter referred to us. At that time, he also presented severe insomnia and his Hamilton Rating Scale for Depression (Ham-D) and Center for Epidemiologic Studies Depression Scale (CES-D) scores were 14 and 12, respectively, thus suggesting the presence of a mild depression. The administration of sertraline was initiated at a dose of 25 mg/day, and 2 weeks later it was increased to 50 mg/day. About one month after the initiation of sertraline, he described sweet foods as a pleasant sweet taste, while salty, sour and bitter foods remained unpleasant. His taste disturbances and appetite loss ameliorated three months after starting the sertraline treatment and has subsequently been maintained on 100 mg/day of sertraline without any taste disturbance.

The most common cause of dysgeusia is the damage of taste cells induced by zinc deficiency,¹ in which total dysgeusia occurs. In the present case, dysgeusia did not disappear with the normalization of serum zinc concentration. Anhedonia, loss of interest in and withdrawal from all regular and pleasurable activities including experiences of sensory pleasures (e.g. taste or smell), is a cardinal feature of major depressive disorder. Recently, Dichter et al reported that anhedonia observed in patients with major depressive disorder is not associated with sensory responses to sweet tastes measured by the sweet taste test.⁴ Thus, the impairment of cognitive function to evaluate pleasurable stimuli might occur in the major depressive disorder. On the other hand, the effect of SSRIs on taste perception could occur at the level of taste receptor cells.⁵ In healthy volunteers, paroxetine, another SSRI, increases both sweet and bitter sensitivity by reducing taste threshold by 27 and 53%, respectively.⁵ In the present case, sertraline might improve taste disturbances by enhancing the serotonergic neurotransmission resulting in the reduction of taste threshold. Dysgeusia is one of neglected symptoms of depression.² Whatever the underlying mechanism, sertraline appears to be an effective treatment for patients suffered from dysgeusia.