Document Type : Original Article
PhD, Department of Psychology, Sari Branch, Islamic Azad University, Sari, Iran
Associate Professor. Department of Psychology. Shahid Beheshti University, Tehran, Iran
Assistant Professor, Department of Psychology, Sari Branch, Islamic Azad University, Sari, Iran
Aim: The purpose of present study was to investigate the effect of Transcranial
direct current stimulation (tDCS) on improvement of executive functions
including working memory, cognitive flexibility, and inhibitory control and
amelioration of depression symptoms. Methods: The research method was
quasi-experimental with pre-test, post-test and followed-up with control group
and the statistical population consisted of 33 women with Major Depression
Disorder (MDD) who were referred to Outpatient Counseling Centers in
districts 1 and 2 affiliated with Education Department in Sari city in 2018.
Using convenience sampling method, 20 individuals were selected and were
randomly assigned into control and experimental groups. The experimental
group received 10 sessions of tDCS for 20 minutes, twice a week. The
computerized version of Wisconsin Card Sorting Test (WCST, Heaton & et al.
1993, N-back Krichner 1958, Go-Nogo Test Hoffman 1984, and Beck
Depression Test 1996 were used for assessment. Data were analyzed using
descriptive indices and mixed analysis of variance with repeated measures.
Results: The results showed that Transcranial direct current stimulation
reduced Beck rating scale (F= 38.68, P= 0.001), errors of WCST (F= 9.82, P=
0.006), it’s total time (F= 8.24, P= 0.010), N–back time (F= 28.09, P= 0.001),
and reaction time of go stage (F= 4.32, P= 0.05) also increased Go-Nogo
accuracy in the go stage (F= 11.66, P= 0.003), nogo stage (F= 15.53, P= 0.001),
and the changes remained untill follow-up session. Although, there wasn't any
significant differences in cluster of WCST (F= 1.53, P= 0.232). Conclusion:
Transcranial direct current stimulation ameliorates cognitive areas, depressive
symptoms, and executive functions. Thus, it can be used as an effective
intervention in the treatment of Major Depression Disorder.