The purpose of this study is to investigate whether transcranial direct-current stimulation (tDCS) will engage reward-related brain circuitry, more specifically the uncinate fasciculus (UF) tract, which connects the orbitofrontal cortex (OFC) and nucleus accumbens (NAcc) regions. Also to evaluate whether the changes in the fractional anisotropy (FA) of the UF tract are associated with changes of clinical symptoms of anhedonia and finally to investigate the moderation role of simulated electric fields (EFs) in an association between FA of the UF and symptoms of anhedonia.
diagnosis of Bipolar Disorder and clinically significant anhedonia
mild symptoms of depression
substance abuse/dependence and any use of drugs (except alcohol or nicotine) in the previous month of the baseline assessment
participants with personality disorder that would interfere with study participation according to clinical judgment
previous neurological conditions (epilepsy, traumatic brain injury, stroke, etc)
any severe, life-threatening non-psychiatric medical condition
Parallel
active tDCS
DeviceSubjects will receive active dose (constant current intensity of 2mA) from the tDCS device for 30 minutes per session for two weeks with no sessions on Saturday and Sunday (Monday to Friday), and one additional session two and four weeks later
sham tDCS
DeviceSubjects will receive a dose from a "sham-tDCS"that is, a device which delivers a different pattern of electric current for 30 minutes per session for two weeks with no sessions on Saturday and Sunday (Monday to Friday), and one additional session two and four weeks later
change in the fractional anisotropy of the uncinate fasciculus
Change in the fractional anisotropy of the uncinate fasciculus as assessed by diffusion tensor imaging (DTI)
changes in symptoms of anhedonia as assessed by the Snaith-Hamilton Pleasure Scale modified for clinical administration (SHAPS-C)
This is a 14 item questionnaire and each is scored from 1 to 4 (1 = Lots of pleasure, 4 = No pleasure)
change in symptoms of anticipatory anhedonia as assessed by the Temporal Experience of Pleasure Scale (TEPS)
The TEPS presents 18 items, 10 of them related to the experience of anticipatory pleasure, and the other 8 related to the ability to experience pleasure at the moment. This is scored on a 6-point Likert scale (1 = very false for me to 6 = very true for me).Total scores vary form 18-108 and lower scores mean higher anhedonia
change in symptoms of consummatory anhedonia as assessed by the Temporal Experience of Pleasure Scale (TEPS)
The TEPS presents 18 items, 10 of them related to the experience of anticipatory pleasure, and the other 8 related to the ability to experience pleasure at the moment. This is scored on a 6-point Likert scale (1 = very false for me to 6 = very true for me).Total scores vary form 18-108 and lower scores mean higher anhedonia
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The University of Texas Health Science Center, Houston
Lead sponsor
Milken Institute
Collaborator
