Marij Bär - Counseling en Coaching

Fifty-five patients originally entered the study. Two patients stopped after one TMS session because of emergency ECT and extreme dizziness, respectively. One patient stopped after five sessions because of extra medication due to suicide risk. Therefore the data for 52 patients were analyzed: 26 sham and 26 rTMS patients. At week 14 the total number of drop-outs was 11 out of 26 sham patients and 14 out of 26 rTMS patients. Sham and rTMS patients did not differ significantly in age and HDRS score before the start of treatment (week 0). No differences between groups were found for sex, left-handedness, right-handedness or ambidexterity, type of depression according to DSM IV criteria, personality disorder, time or reason for drop-out, ECT before treatment, medication, side effects of treatment, inpatient or outpatient, or age older than 65 years.

During the treatment period, depressive symptoms improved in both groups (decrease >20% HDRS) (Figure 1), but there was no statistically significant difference between the groups. However, in the post-treatment period, differences between the two groups emerged. Twelve weeks after termination of rTMS treatment, HDRS scores of less than 10 were only found in 4 rTMS patients (14%), all of whom were men. Moreover a decrease in HDRS score of more than 50% was found in 5 out of 26 patients (19%) in the rTMS group (4 men, 1 woman), while 4 out of 26 patients (15%) who received sham treatment responded (all women).

Table 2. differences in mean Hamilton scores in rTMS and sham groups in weeks 0-14, analyzed by T-Test (standard deviations in parentheses).

rTMS = repetitive Transcranial Magnetic Stimulation
HDRS = Hamilton Depression Rating Scale

Table 3. Differences in demographic and clinical variables analyzed by chi-square-test (standard deviations in parentheses).

Table 4. Reasons for dropout after completion of stimulation sessions.
Other = other reasons for dropout; ECT, holiday, no-show, moved to other treatment.

The random effects regression model revealed a significant decrease in HDRS scores during treatment (on average to 89% of ‘week 0’), but no significant difference between the rTMS and sham groups. The HDRS score decreased by about 2.5 points in the first week and by about 1 point in the second week in both groups. Thus there was an improvement of more than 10% in all patients. However, in the post-treatment period the two groups became progressively different, resulting in a significant mean difference of more than 4 points in HDRS score between the sham and rTMS groups. On average, women had higher scores (2 points) than men, and patients older than 65 years had higher scores (about 3 points) than younger patients. Somewhat unexpectedly, left-handed or ambidextrous patients had mean HDRS scores that were 3 or more points lower than those of other patients (see Table 5).

There were large individual differences, particularly in the post-treatment period. The overall between-patient variance was more than 12, indicating a standard deviation of approximately 3.5 HDRS points. The measurement variance was also about 12. The between-patient variance became larger in the post-treatment period, where the variance increased by more than 30 HDRS points, leading to an approximate standard deviation of 6.6 HDRS points. The largest variance, however, was associated with the change in HDRS score post treatment, as indicated by the so-called random slope. Therefore, although the average improvement was 1.10 HDRS points, the change varied enormously among patients (approximate standard deviation over 7 points), implying that in some patients the HDRS score increased after treatment. This large variability may also have masked differences between completers and drop-outs, which were found to be not significant.

Table 5. Results from the random effect regression model. Parameter Estimates, SE ‘s and p-values.