Table 2. Characteristics at follow-up by the groups of mood disorders developed between 2008 and 2012 and the control group.
| Controls (n=106) | Major depressive disorder (n=28) | Minor depressive disordera (n=39) | Minor depressive episodeb with history of MDE (n=8) | P-value | |
|---|---|---|---|---|---|
| Age at psychiatrists' assessments, years | 81.8 (2.3) | 80.5 (2.4) | 81.5 (2.6) | 81.6 (3.2) | 0.066 |
| MMSE at psychiatrists' assessments, points | 27.8 (2.0) | 27.9 (1.9) | 28.3 (2.1)c | 27.3 (2.0) | 0.457 |
| Onset age of current episode of depression, years | 79.5 (2.5) | 80.7 (2.7)c | 80.6 (3.2) | 0.208 | |
| Duration of illness,d months | 11.3 (10.8) | 11.1 (10.3)c | 11.1 (4.6) | 0.998 | |
| HAMD score,d points | 15.7 (3.8) | 9.3 (1.8) | 10.3 (1.7) | 0.000 | |
| Antidpressant use during follow-up period, % | — | 7.1e | — | — | |
| Having history of major depressive episodes, % | 21.4 | 100.0 | |||
| Antidepressant use in the previous MDE, % | 3.6 | — | |||
| Living alone, % | 41.5 | 28.6 | 38.5 | 50.0 | 0.580 |
| Smoker, % | 5.7 | — | — | 0.222 | |
| Drinking alcohol 5 days or more per week, % | 9.4 | 3.6 | 2.6 | — | 0.337 |
| Sports or exercise activity with 1 day or less per week, % | 74.5 | 67.9 | 87.2 | 37.5 | 0.021 |
| Body mass index, kg/m2 | 22.6 (4.0) | 21.3 (3.1) | 21.5 (3.2) | 23.2 (3.0) | 0.165 |
| History of heart diseases, % | 17.0 | 28.6 | 20.5 | 28.6 | 0.529 |
| Time difference between baseline survey and onset of current episode, months | 48.0 (0.0)f | 27.8 (13.0) | 29.1 (13.8)c | 37.8 (4.5) | 0.000 |
| Blood drawing in the afternoon, % | 50.9 | 53.6 | 51.3 | 87.5 | 0.256 |
| Fasting at blood drawing, % | 1.9 | — | 2.6 | — | 0.840 |
| Storage duration of sera,d months | 4.0 (0.0) | 11.4 (15.6) | 17.0 (17.9) | 4.0 (0.0) | 0.000 |
Abbreviations: HAMD, GRID–Hamilton Rating Scale for Depression; MDE, major depressive episode; MMSE, Mini-Mental State Examination.
Mean values (s.d.) were shown as long as % was not indicated in the first column.
Minor depressive disorder was diagnosed according to the criteria sets for further study in Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV).41
Minor depressive episode was defined as depression that meets the criteria for minor depressive disorder except that there had never been a major depressive episode or a dysthymic disorder.
One missing value.
Duration of illness, time period between the beginning of the latest episode and the follow-up survey; storage duration of sera, time period between blood drawing and brain-derived neurotrophic factor assay. Values for these items were shown for 10 persons with current episode of major depressive disorder, 37 persons with current episode of minor depressive disorder and 8 persons with current episode of minor depressive episode with MDE history.
They were the same persons who were identified as being under treatment at follow-up.
Time of the 2012 follow-up were used instead of onset time of onset of current episode.