This study linked baseline and 12 month postal surveys in a general population sample with primary care medical records. Those receiving primary care for mood disorders did not have better outcomes in terms of remission of their insomnia symptoms. In those reporting insomnia at baseline, three-quarters of those receiving health care management still had symptoms at follow-up.
This study found persistent insomnia symptoms were higher in people prescribed hypnotic drugs, but there was no association with antidepressant use. Foley et al. also found a close relationship between sedative medication and persistence of insomnia symptoms over 3 years in an elderly population in the community . In elderly women (aged 70-75 yrs) Byles et al. found that over 75% of those taking hypnotics at baseline continued to take these drugs at follow-up 4 years later  Belleville et al. found that withdrawal of hypnotics over an 8 week period in a group of chronic users of this medication resulted in over 68% of participants in the study being drug free, and 51% still being drug free at 6 months. This was independent of whether or not the tapering dose of hypnotics was combined with self-help CBT in the form of a graded program of literature . Tom et al. in their cohort of middle aged women studied over six years found that persistence of insomnia was related both to psychiatric and physical symptoms and a past history of insomnia .
Regardless of primary care use, two-thirds of this sample still had insomnia symptoms at follow-up. This suggests that in most people with insomnia symptoms in the community these symptoms are chronic. The majority did not consult or have a prescription for this problem, some possibly choosing to self medicate. Our previous work showed a clear link between insomnia and depression, this non-consulting group may have unmet need such as depression . Alternatively they may see that primary care is routinely only offering drug treatments with possible side effects. Horne, for example, suggests that some people perceive medication negatively as unnatural or dangerous and prefer to self-medicate . Included in this group will also be some with milder symptoms.
Remission is seen in one-third of people with insomnia at baseline who do not have a consultation or prescription. This no doubt represents the temporary nature of the insomnia stimulus in some but is broadly in agreement with Foley et al. who found a 48% remission of insomnia after 3 years in the community on no sedative medication, decreasing to 33-37% at follow-up when sedative medication was taken . Janson et al. found a remission rate of 65% in men aged 30-69 yrs after a 10 year follow-up, associated with smoking cessation and weight loss, although medication use was not recorded . Even in the more severe insomniacs found in a sleep medicine clinic in the US, Rosenthal et al. (2008), reported the remission of insomnia over 3 to 5 years to be 26% . In Morin et al's general population study of those complaining of poor sleep, 31% had what was described as insomnia syndrome, which included those who were dissatisfied with sleep and having insomnia for 3 nights a week for at least a month or those who took hypnotics. At 3 year follow-up 30% of the insomnia syndrome group had persistence of their symptoms and only 8% of this group had spontaneous remission .
Hypnotic use appears associated with an increased likelihood of persistence. There are several interpretations of this result. Hypnotic medication may be ineffective in the long-term in primary care and potentially exacerbates the problem, this exacerbation may be due to a specific problem of tolerance and addiction related to both persistence and medication use . The group of people with insomnia who receive prescriptions for hypnotics may in some way be "different" to people who do not take hypnotics or do not consult primary care, in ways which might explain poor outcome despite medication.
Whatever the explanation, however, primary care is having little impact on community levels of chronic insomnia with its current range or style of medications. However cognitive behavioural therapy (CBT) may be as effective and with less side effects than medication . Internet-based CBT may be attractive in that it is a low-cost alternative to face to face CBT . The GP may wish first to give sleep hygiene advice or organise CBT if this is available when faced with a patient with complaints of insomnia.
A strength of this study is its longitudinal design with surveys at baseline and 12 months linked by consultation and prescription data. Associations were adjusted for age, gender, and number of pain areas, all of which have been shown to be related to both insomnia and health care use . Existence of other chronic illnesses, for example cardiac, respiratory disease or diabetes, were not measured and may be associated with insomnia and hence may have an influence on the results . We did not measure over the counter medication which may have been used to self-treat insomnia. Response at baseline was 56% and there were some age and gender differences in response. As with all cohort studies, there was further attrition at follow-up. However, there were few differences between those completing follow-up questionnaires and those who did not in demographics, self-reported anxiety or depression, self-reported pain, or health care use for a mood disorder. Whilst any selective non-response may affect the overall estimates of rates of consultation and prescription, it is unlikely to affect the associations found.
Consultation data for mood problems and prescriptions for hypnotics and antidepressants were examined for 1 year between the questionnaires at baseline and follow-up, so it was not possible to ascertain whether health care use was new or ongoing. The study was set in North Staffordshire, UK, an area more deprived than the UK average. However data were collected from five general practices which should reduce the likelihood that health care use was influenced by unusual practice characteristics.