Differential effects of deep TMS of the prefrontal cortex on apathy and depression.
BACKGROUND
Apathy is one hallmark of major depression (MDD). It is distinguished by lack of emotion, whereas other aspects of depression involve considerable emotional distress. Investigating both apathy and depression may increase the degree of treatment efficacy for both ailments together and apart.


OBJECTIVE
Evaluate the differential effects of deep transcranial magnetic stimulation (DTMS) over the prefrontal cortex (PFC) on apathy and other aspects of depression in patients suffering from a depressive episode.


METHODS
Fifty-four treatment-resistant MDD patients were evaluated with the Hamilton Rating Scale for Depression (HRSD), and then treated with DTMS. Apathy-related items from HRSD (ApHRSD) were compared with the remaining items from HRSD (DepHRSD). Antidepressant medications were withdrawn and active DTMS treatment was administered at 20 Hz, 5 days a week for 4 weeks. Changes in HRSD were recorded. Primary efficacy time point was 1 week after the end of active treatment.


RESULTS
At screening, ApHRSD distribution was unimodal (moderate apathy), with low correlation (r = 0.17) between ApHRSD and DepHRSD. After treatment, a third had remitted apathy, and the correlation between ApHRSD and DepHRSD had dramatically increased (r = 0.83). Severe ApHRSD (≥ 7) at screening correlated with nonremission for both ApHRSD (R(2) = 0.1993, P = .0012) and DepHRSD (R(2) = 0.0860, P = .0334).


CONCLUSIONS
DTMS over the PFC improved both apathy and depression similarly. However, DTMS did not lead to MDD remission if ApHRSD at screening was ≥ 7 of 12. Further investigation using a larger sample will determine whether screening apathy at baseline could be used to predict efficacy of DTMS in MDD patients.
Cognitive and Emotional Laboratory, Shalvata Mental Health Care Center, Hod-Hasharon, Israel.
Yechiel
Y
Levkovitz
Aharon
A
Sheer
Eiran V
EV
Harel
Leor N
LN
Katz
Dana
D
Most
Abraham
A
Zangen
Moshe
M
Isserles
D000293:Adolescent; D000328:Adult; D000368:Aged; D057565:Apathy / Q000502:physiology*; D003863:Depression / Q000503:physiopathology* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000502:physiology*; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D050781:Transcranial Magnetic Stimulation; D016896:Treatment Outcome; D055815:Young Adult