Effects of TMS on anhedonia and suicidal ideation in treatment-resistant depression: Outcomes from the University of Minnesota Interventional Psychiatry Program

Abstract

Background

A developing literature suggests that transcranial magnetic stimulation (TMS) can target anhedonia and suicidal ideation (SI), core symptoms of treatment-resistant depression (TRD). This present naturalistic study extends the existing literature by investigating the connection between changes in anhedonia and suicidal ideation (SI) related to transcranial magnetic stimulation (TMS), independent of any overall changes in depression.

Methods

Pre and post treatment PHQ-9 and IDS-SR data were collected from 181 TRD patients who received dorsolateral prefrontal cortex ( dlPFC) TMS using the Figure-8 or H1-coil. Changes in overall depression symptoms, anhedonia, and SI were analyzed using chi square tests, repeated measure ANOVAS, and linear regression for repeated measures.

Results

TMS yielded changes in overall depression symptoms (PHQ-9 Cohen’s d = 1.02; IDS-SR Cohen’s d = 1.05), with 23.9 % and 41.7 % of patients experiencing response as measured by IDS-SR and PHQ-9, respectively. TMS treatment was also associated with large changes in both anhedonia (d = 1.03) and SI (d = 0.88), which were similar in magnitude to changes in all other depression symptoms (d = 0.97). Importantly, changes in anhedonia predicted changes in SI, even after controlling for baseline depression severity and change in other depression symptoms.

Limitations

The lack of a control arm and a neuroimaging measure temper mechanistic conclusion.

Conclusion

Our results reinforce the effectiveness of TMS in TRD and provide new evidence that anhedonia and SI may belong to a broader symptom cluster potentially undergirded by a shared circuitry accessible to dlPFC TMS.