Diminished effort on a progressive ratio task in both unipolar and bipolar depression.

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TitleDiminished effort on a progressive ratio task in both unipolar and bipolar depression.
Publication TypeJournal Article
Year of Publication2016
AuthorsHershenberg, R, Satterthwaite, TD, Daldal, A, Katchmar, N, Moore, TM, Kable, JW, Wolf, DH
JournalJ Affect Disord
Volume196
Pagination97-100
Date Published2016 May 15
ISSN1573-2517
KeywordsAdolescent, Adult, Anhedonia, Bipolar Disorder, Case-Control Studies, Depressive Disorder, Major, Female, Humans, Male, Middle Aged, Motivation, Reward, Young Adult
Abstract

BACKGROUND: Amotivation, or decisional anhedonia, is a prominent and disabling feature of depression. However, this aspect of depression remains understudied, and no prior work has applied objective laboratory tests of motivation in both unipolar and bipolar depression.METHODS: We assessed motivation deficits using a Progressive Ratio Task (PRT) that indexes willingness to exert effort for monetary reward. The PRT was administered to 96 adults ages 18-60 including 25 participants with a current episode of unipolar depression, 28 with bipolar disorder (current episode depressed), and 43 controls without any Axis I psychiatric disorders.RESULTS: Depressed participants exhibited significantly lower motivation than control participants as objectively defined by progressive ratio breakpoints. Both the unipolar and bipolar groups were lower than controls but did not differ from each other.LIMITATIONS: Medication use differed across groups, and we did not have a separate control task to measure psychomotor activity; however neither medication effects or psychomotor slowing are likely to explain our findings.CONCLUSIONS: Our study fills an important gap in the literature by providing evidence that diminished effort on the PRT is present across depressed patients who experience either unipolar or bipolar depression. This adds to growing evidence for shared mechanisms of reward and motivation dysfunction, and highlights the importance of improving the assessment and treatment of motivation deficits across the mood disorders spectrum.

DOI10.1016/j.jad.2016.02.003
Alternate JournalJ Affect Disord
PubMed ID26919058
PubMed Central IDPMC4808384
Grant ListP50MH096891 / MH / NIMH NIH HHS / United States
K23 MH098130 / MH / NIMH NIH HHS / United States
R01 MH101111 / MH / NIMH NIH HHS / United States
K23MH098130 / MH / NIMH NIH HHS / United States
R01MH107703 / MH / NIMH NIH HHS / United States
K23MH085096 / MH / NIMH NIH HHS / United States
K23 MH085096 / MH / NIMH NIH HHS / United States
R01MH101111 / MH / NIMH NIH HHS / United States
R01 MH107703 / MH / NIMH NIH HHS / United States
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