Inclusion Criteria- Consecutive admission due to first or recurrent ischemic stroke (image proved) and stroke occurred in preceding 4 weeks before admission. The onset of stroke was defined as the occurrence of abnormal neurological symptoms according to the patients' statement. The following period is 12 months after being included (for the first and third study aims), and follow for another 24 months to study the immunological aspect of PSD (for the second study aim).
Exclusion Criteria- TIA (transit ischemic attack)
- Impairment of communication or cognitive function (MMSE<15)
- Past history of depression, psychosis, severe substance abuse
- Taking antidepressants at least 2 weeks prior to stroke
- Concurrent possible depression (Ham-D>10)