Chronic Insomnia Predicts Anxiety, Often Coexists With Depression and Anxiety

Marlene Busko

July 13, 2007

July 13, 2007 — A large prospective 11-year study in Norway found that chronic insomnia is a risk factor for developing anxiety but not for developing depression, although often anxiety and depression are present with insomnia.

The study, led by Dag Neckelmann, MD, from Haukeland University Hospital, in Bergen, Norway, is published in the July issue of Sleep.

The researchers write that insomnia is the subjective feeling of having difficulties initiating or maintaining sleep (DIMS) or having nonrestorative sleep. They conclude that their results imply that "individuals reporting DIMS, in addition to receiving adequate treatment for their sleep disturbance, should be carefully examined for the presence of anxiety disorder as well as depression."

A press release about this study issued by the American Academy of Sleep Medicine (AASM) notes that insomnia is the most commonly reported sleep disorder, and while about 30% of adults have insomnia symptoms, less than 10% of adults are likely to have chronic insomnia.

The investigators write that previous studies suggested that insomnia causes depression and/or anxiety disorders, but most studies were either cross-sectional or had a short follow-up of 1 to 2 years. They aimed to examine the relationship between insomnia and the development of anxiety disorders and depression in a population-based sample.

The team looked at data from 2 general health surveys of the adult population in the Nord-Trondelag county of Norway: the HUNT-1 study, performed in 1984–1986 and the HUNT-2 study, performed in 1995–1997. The current study analyzed data from 25,130 adults who were aged 20 years or older at the time of HUNT-1 and HUNT-2 and excluded individuals who reported significant anxiety or depression in HUNT-1.

The study subjects were classed into 4 groups based on the presence or absence of insomnia in the 2 surveys. The presence or absence of anxiety or depression at the time of the second survey (HUNT-2) was assessed based on self-rated symptoms from the Hospital Anxiety and Depression Scale.

Strong Risk Factor for Anxiety

Compared with individuals without chronic insomnia at the time of the initial survey, those who reported chronic insomnia at that time had a significantly increased risk of having an anxiety disorder 11 years later. This relationship was not seen for insomnia and depression, although having insomnia was associated with coexisting depression (and with coexisting anxiety).

Risk for Depression or Anxiety in HUNT-2 Based on History of DIMS

Presence of DIMS
Depression in HUNT-2,
Odds Ratio (95% CI)
Anxiety in HUNT-2,
Odds Ratio (95% CI)
None in HUNT-1 or HUNT-2
1.0
1.0
Only in HUNT-1
1.2 (0.8 – 1.8)
1.6 (1.1 – 2.3)
Only in HUNT-2
1.8 (1.6 – 2.0)
3.4 (0.8 – 1.8)
HUNT-1 and HUNT-2
1.1 (0.8 – 1.6)
4.9 (3.8 – 6.4)
DIMS (chronic insomnia) = difficulties initiating or maintaining sleep.
HUNT-1 = Nord-Trondelag Health Study, performed in 1984–1986.
HUNT-2 = Nord-Trondelag Health Study, performed in 1995–1997.

The investigators conclude: "Focus on DIMS as a symptom of both anxiety and depression may facilitate the early detection of a mental disorder as well as the detection of comorbidity. Though not demonstrated, alleviating DIMS may reduce the risk of developing anxiety disorders."

Clinical Implications

Donna Arand, PhD, from the Sleep Disorders Center at Kettering Hospital, in Dayton, Ohio, and a spokesperson for the AASM, who was not involved in the study, told Medscape: "The long time period and large sample size makes this study notable. More important, this is the first study to clearly show that chronic insomnia is a risk factor for the development of anxiety disorders." She noted that, unlike previous studies, this study did not find that chronic insomnia is a risk factor for the development of depression, but it did replicate previous findings that chronic insomnia often coexists with anxiety disorders and depression.

Dr. Arand added that the clinical implications of this study are that individuals with chronic insomnia will likely also have anxiety disorders and depression. Thus, they will need to be evaluated for these disorders and, if present, treated for them. "Since chronic insomnia often appears as the first problem, it needs to be recognized as a strong risk factor for anxiety, and consequently, chronic insomnia patients need to be followed long term and evaluated for these other conditions," she advised.

Sleep. 2007;30:873-880.

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