Self-Limited Kleptomania Symptoms as a SideEffect of Duloxetine

Impulse control disorders (ICDs) have been described as a side effect of dopamine agonists, frequently used inneurodegenerative conditions affecting the nigrostriatal pathway. Serotonin-norepinephrine reuptake inhibitors (e.g., duloxetine)have dose-dependent differential affinity for monoaminergic transporters, inhibiting the dopamine transporter at higher doses,thus increasing availability of synaptic dopamine, with the potential for similar impulse control side effects.Case Presentation.A19-year-old Asian-American female with a history of depression developed new-onset stealing behaviors after an increase in herdose of duloxetine from 60 mg to 90 mg; she described these actions as “compulsive” and irresistible, later experiencing eitherrelief or guilt, features compatible with an ICD. Her symptoms eventually subsided with continued use of 90 mg of duloxetine.Discussion. To the knowledge of the authors, this is the first report of a patient developing new-onset ICD behaviors after beingplaced on a higher dose of duloxetine, which can inhibit the dopamine transporter and cause difficulty with impulse control. Theself-resolving nature of the symptoms may result from compensatory upregulation of dopamine transporters, increasing reuptakeof dopamine. Asian populations may be at a higher risk due to the frequent occurrence of CYP2D6 polymorphisms, which decreasethe conversion of duloxetine to its inactive metabolites.