Prevalence and Clinical Correlates of Insomnia in Depressive Disorders: The CRESCEND Study.
OBJECTIVE
To investigate the prevalence, clinical manifestations, and clinical correlates of insomnia in a large cohort of Korean patients with depressive disorders.


METHODS
We recruited 944 patients with depressive disorders from the Clinical Research Center for Depression of South Korea (CRESCEND) study. Psychometric scales were used to assess depression (HAMD), anxiety (HAMA), psychotic symptoms (BPRS), global severity (CGI-S), and functioning (SOFAS). Insomnia levels were determined by adding the scores for all items on the HAMD insomnia subscale. The clinical characteristics of the patients with 'low insomnia' (summed score ≤3 on the HAMD subscale) and 'high insomnia' (score ≥4) were compared using statistical analyses. A logistic regression model was constructed to identify factors associated with 'high insomnia' status.


RESULTS
Symptoms of insomnia were present in 93% of patients, while simultaneous early, middle, and late insomnia affected 64.1%. The high insomnia patients were characterized by significantly greater age, higher symptom levels (including core, gastrointestinal somatic and anxiety symptoms, and suicidal ideation), higher global severity and incidence of physical disorders, and greater insight. Explanatory factors of 'high insomnia' status were older age, higher gastrointestinal somatic and anxiety symptom levels, higher global severity, and greater insight.


CONCLUSIONS
In clinical psychiatry, insomnia has been significantly underdiagnosed and undertreated. It affects most patients with depressive disorders, and is indicative of the global severity of depression. Active efforts to diagnose and treat insomnia in patients with depressive disorders should be strongly encouraged. Further research is needed to improve the diagnosis and treatment of insomnia in depressive patients.
Department of Psychiatry, Yong-In Mental Hospital, Yongin, Republic of Korea. ; Institute of Mental Health, Hanyang University, Seoul, Republic of Korea.
Seon-Cheol
SC
Park
Department of Psychiatry, School of Medicine, Chonnam National University, Gwangju, Republic of Korea.
Jae-Min
JM
Kim
Department of Psychiatry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
Tae-Youn
TY
Jun
Department of Psychiatry, College of Medicine, Korea University, Seoul, Republic of Korea.
Min-Soo
MS
Lee
Department of Psychiatry, Keimyung University School of Medicine, Daegu, Republic of Korea.
Jung-Bum
JB
Kim
Department of Preventive Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
Seung-Hee
SH
Jeong
Institute of Mental Health, Hanyang University, Seoul, Republic of Korea. ; Department of Psychiatry, College of Medicine, Hanyang University, Seoul, Republic of Korea.
Yong Chon
YC
Park
Anxiety symptoms; Depressive disorders; Gastrointestinal somatic symptoms; Global severity; Insomnia