Depression and antidepressant use, especially selective serotonin reuptake inhibitors (SSRIs), are common in Parkinson disease (PD). The objective of this clinical trial was to assess the efficacy of atomoxetine, a selective norepinephrine reuptake inhibitor (SNRI), for the treatment of clinically significant depressive symptoms and common comorbid neuropsychiatric symptoms in PD.
A total of 55 subjects with PD and an Inventory of Depressive Symptomatology–Clinician (IDS-C) score ≥22 were randomized to 8 weeks of atomoxetine or placebo treatment (target dosage = 80 mg/day). Depression response (>50% decrease in IDS-C score or Clinical Global Impression–Improvement [CGI-I] score of 1 or 2) was assessed using intention-to-treat modeling procedures. Secondary outcomes included global cognition, daytime sleepiness, anxiety, apathy, and motor function.
There were no between-groups differences in a priori–defined response rates. Using a more liberal response criterion of >40% decrease in IDS score from baseline, there was a trend (p = 0.08) favoring atomoxetine. Patients receiving atomoxetine experienced significantly greater improvement in global cognition (p = 0.003) and daytime sleepiness (p = 0.001), and atomoxetine was well-tolerated.
Atomoxetine treatment was not efficacious for the treatment of clinically significant depressive symptoms in PD, but was associated with improvement in global cognitive performance and daytime sleepiness. Larger studies of SNRIs in PD for disorders of mood, cognition, and wakefulness are appropriate.
Classification of evidence:
This interventional study provides Class II evidence that atomoxetine (target dosage = 80 mg/day) is not efficacious in improving clinically significant depression in PD.
|ADHD||= attention-deficit/hyperactivity disorder;|
|AS||= Apathy Scale;|
|CGI-I||= Clinical Global Impression–Improvement;|
|CI||= confidence interval;|
|dPD||= depression in Parkinson disease;|
|DSM-IV||= Diagnostic and Statistical Manual of Mental Disorders, 4th edition;|
|ESS||= Epworth Sleepiness Scale;|
|GDS-15||= 15-item Geriatric Depression Scale;|
|ICC||= intraclass correlation coefficient;|
|IDS-C||= Inventory of Depressive Symptomatology–Clinician;|
|LC||= locus ceruleus;|
|MMSE||= Mini-Mental State Examination;|
|NNT||= number needed to treat;|
|OR||= odds ratio;|
|PD||= Parkinson disease;|
|SNRI||= selective norepinephrine reuptake inhibitor;|
|SSRI||= selective serotonin reuptake inhibitor;|
|STAI||= State Anxiety Inventory;|
|TCA||= tricyclic antidepressant;|
|UPDRS||= Unified Parkinson's Disease Rating Scale.|