Lurasidone adjunctive with antidepressants in an elderly patient with severe illness anxiety disorder

To the Editor

Illness anxiety disorder (IAD) has a late age of onset, and elderly patients with symptoms of illness anxiety are prone to have depression, worse disability and higher healthcare expenditure. However, there is still paucity of knowledge with regard to effective pharmacological treatment for IAD in late life.

Lurasidone, a second-generation antipsychotic (SGA), has recently been approved for both schizophrenia and bipolar depression. Accumulating evidence also indicates its safety and effectiveness for older adults. Here is a case of a geriatric patient with severe IAD and comorbid depression who achieved remission of her preoccupation after treatment with lurasidone adjunctive with antidepressants.

A 62-year-old housewife developed a preoccupation with the idea that she had a severe illness in relation to her oral cavity and esophagus after a dentist visit for dental plaque in November 2016. She then had complaints including toothache while chewing, dry mouth with a burning sensation, difficulty in swallowing, feeling of choking and abdominal distress. She visited our emergency department four times in a week and asked for further treatment, even though examinations revealed no specific findings. Symptoms of depression were also noted, including depressed mood, anhedonia, negative thoughts, insomnia and three suicide attempts. The patient had intact sense of reality, and the possibility of psychosis had been excluded. She met the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5) criteria for IAD and a major depressive episode.

Antidepressants were prescribed with a combination of escitalopram and bupropion in August 2017. Her symptoms improved to a limited extent after 5 months of treatment. However, she continued seeking medical reassurance, even though her depressive mood partially remitted. In January 2018, she received adjunctive treatment with lurasidone 20 mg per day for 1 week, after which her symptoms of illness anxiety and depression dramatically improved. Currently, she can eat without discomfort and is not preoccupied with any disease.

SGAs have been widely used as adjunctive therapy to antidepressants in patients with refractory anxiety symptoms. It has been proposed that antagonism at 5-HT2A receptors and/or agonist activity at 5-HT1A receptors of SGAs may be the mechanisms of the anxiolytic effects. Besides, SGAs have been shown to be effective in improving psychiatric patients’ cognitive inflexibility, which involves dopaminergic dysfunction (Ducasse et al., 2014). In the current case, lurasidone, a SGA, may have played a role in reducing the patient’s disease conviction. Compared to other SGAs, lurasidone has been demonstrated to have procognitive effects in psychiatric patients due to its lack of D4 dopamine receptor affinity (Murai et al., 2014). Improved cognition may be associated with insight enhancement and thus beneficial for such patient’s treatment (Harvey et al., 2017).