Monthly variation in prevalence rates of comorbid depression and anxiety in the general population at 63–65° North: The HUNT study

Stordal, Eystein; Morken, Gunnar; Mykletun, Arnstein; Neckelmann, Dag; Dahl, Alv A.

doi:10.1016/j.jad.2007.07.007

« Previous Next »Journal of Affective Disorders
Volume 106, Issue 3 , Pages 273-278, March 2008

Monthly variation in prevalence rates of comorbid depression and anxiety in the general population at 63–65° North: The HUNT study

Eystein Stordal
- Department of Psychiatry, Helse Nord-Trondelag HF, Hospital Namsos, Namsos, Norway
- Department of Neuroscience, Norwegian University for Science and Technology (NTNU), Trondheim, Norway
- Corresponding author. Department of Psychiatry, Hospital Namsos, N-7800 Namsos Norway. Tel.: +47 74215400; fax: +47 74215469.
Gunnar Morken
- Østmarka Psychiatric Department, St.Olavs Hospital, Norway
- Department of Neuroscience, The Medical Faculty, NTNU, Trondheim, Norway
Arnstein Mykletun
- Research Centre for Health Promotion, Faculty of Psychology, University of Bergen, Norway
Dag Neckelmann
- Solli Nervesanatorium, Department of Psychiatry, University of Bergen, Norway
Alv A. Dahl
- The Cancer Clinic, Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Norway

Received 15 November 2006; received in revised form 9 July 2007; accepted 9 July 2007.

Abstract

Background

To investigate monthly variation in depression, anxiety and their comorbidity (COM) in an epidemiologic study and their association to monthly variation in suicide rates.

Methods

60,995 participants of the Health Study of Nord-Trøndelag County in 1995–97 rated themselves on the Hospital Anxiety and Depression Scale (HADS) in all months except July. All 10,670 male and 3833 female suicides in Norway from 1969 through 1996 were included.

Results

The prevalence of comorbid anxiety and depression was highest in spring (April, May) and in October (p<0.01). There was a correlation between the monthly variation in the national suicide rate and monthly variation in comorbid anxiety and depression (r=0.72, df=11, p=0.01) and for male alone (r=0.67, df=11, p=0.03). There was also a significant monthly variation in the prevalence of depression (p<0.001) and no monthly variation in the prevalence of anxiety.

Limitations

Limited information about the third of the population who did not take part in the HUNT-2 Study. HADS based depression and anxiety cover psychological symptoms, not somatic and social ones. In relation to DSM-IV and ICD-10 defined anxiety disorders and depressions, the sensitivity and specificity of HADS caseness, give a considerable number of false-positive cases.

Conclusions

Increased prevalence of comorbid depression and anxiety in males during spring, and its association with suicidality should have clinical importance, as identification and treatment could influence suicide rates.

Keywords: Monthly variation, Comorbid anxiety, Depression