(C) 1997 Martin Dunitz Ltd
International Journal of Psychiatry in Clinical Practice 1997 Volume I Pages 107- 1 1 7
107
Int J Psych Clin Pract Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/25/14 For personal use only.
Assessment and treatment of insomnia (including a case control study of patients with Primary Insomnia) ANN L SHARPLEY, MARY E J ATTENBURROW AND PHILIP J COWEN Psychopharmacology Research Unit, Littlemore Hospital, Oxford
Correspondence Address Dr A L Sharpley, Psychopharmacology Research Unit, Littlemore Hospital, Littlemore, Oxford OX4 4XN Tel 01865 223130 Fax 01865 775 212
Received 27 January 1997; accepted for publication 9 April 1997
Insomnia is a subjective term describing the perception of disturbed or inadequate sleep. Causes include medical diseases, psychiatric disorders, drugs, behavioural factors, circadian dysrhythmias and primary sleep disorders. Insomnia is common, affecting approximately one-third of the total population, and of these about 10%consider it a chronic problem. Insomnia is more common infemales and increases with age. Many people with insomnia resort to ineffective or dangerous self-treatment regimens and the combination of alcohol with non-prescription drugs is common. We have carried out a study on 20 patients with Primary Insomnia and were able to demonstrate significant dgerences in both descriptive and objective EEG data between those with Primary Insomnia and controls. Careful evaluation of the sleep problem and accurate diagnosis are essential in order to choose the right treatment for an individual patient. When a specific problem is identified (psychiatric, physical, behavioural), then the underlying cause needs to be treated. Insomnia can be treated by either non-pharmacological or pharmacological intervention, and often both are used simultaneously. It is recommended that hypnotic treatments should be used for no more than one month. (Int J Psych Clin Pruct 1997; 1:107- 117)
Keywords primnry insomnia treatment sleep hygiene
INTRODUCTION
T
he word ‘insomnia’ comes from Latin and means ‘no sleep’. The complaint is subjective, and the word describes the perception of disturbed or inadequate sleep-i.e. sleep that is difficult to initiate or maintain, or that is non-refreshing or non-restorative-and is usually associated with changes in daytime functioning and well-being. Causes include medical diseases, psychiatric disorders, drugs both prescribed and non-prescribed (including alcohol), behavioural factors, circadian dysrhythmias and primary sleep disorders. Conversely, a broad definition of a ‘good night’s sleep’ is that a person takes less than 30 minutes to fall asleep, maintains sleep for 6-8 hours with only a couple of brief awakenings and feels well-rested and refreshed upon waking.
assessment hypnotics
Insomnia can cause significant deterioration in the quality of life, including difficulties with concentration, memory, ability to accomplish daily tasks, and enjoyment of interpersonal relationships. The ability to cope with minor irritations is also significantly impaired. It has been reported that 10%of people who complain of insomnia fall asleep while visiting friends.’
MOTORVEHICLEACCIDENTS Between 1% and 10% of motor vehicle accidents are directly related to sleepines2 People suffering from insomnia are more than twice as likely as good sleepers to report vehicle accidents in which fatigue was a factor. The Stanford Sleep Disorders Clinic statistics show that 15-45% of all patients suffering from sleep apnoea and 12-30% suffering from narcolepsy have had at least one
108
AL Sharpley et al
Int J Psych Clin Pract Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/25/14 For personal use only.
accident related to sleepiness; 2 -8Oh of patients with insomnia also admitted at least one accident related to sleepiness. Considering the number of people suffering from insomnia (rather than from sleep apnoea or narcolepsy), the impact of insomnia on accident statistics plus the economic cost of such accidents is seen to be It is not surprising that over 50% of ~onsiderable.~ accidents occur at night when the propensity to sleep is at its peak.4 It appears that sleepiness is generally a very underrated factor in accidents.
EPIDEMIOLOGY Insomnia is common. According to various epidemiological studies in the USA, there is general agreement that approximately one-third of the total population suffers from insomnia, and of these about 10% consider it a chronic A recent WHO collaborative study in 15 different countries has shown a similar pattern of insomnia and, like the US studies, found that insomnia is more common in females and increases with age.5 The tendency to seek medical advice increases with age, as does the propensity to take daytime naps. Indeed, it is thought that half of the population over 65 years of age suffer from chronic sleep disturbances.' The WHO study found that 51% of people with an insomnia complaint also had a welldefined ICD-109 mental disorder such as depression, anxiety or alcohol problems.
CLASSIFICATION OF INSOMNIAS The longer insomnia lasts, the more complex its management becomes. It can be divided into three groups according to duration. 1. Transient insomnia lasts for a few days. Most people will suffer from this from time to time, and it is often associated with a specific event such as examination stress, jet lag or environment. Sleep-promoting medication are appropriate and can be used prophylactically. 2. Short-term insomnia lasts for a matter of weeks, and is usually associated with stress or medical illness. 3 . Chronic insomnia lasts for months or perhaps years, and has multiple contributing factors. In clinics specializing in sleep disorders, approximately 15%25% of individuals with chronic insomnia are diagnosed as having Primary Insomnia."
Traditionally, insomnia has been classified as sleeponset insomnia, sleep-maintenance insomnia and early morning awakening. However, this classification is only useful if the type of insomnia remains stable over time. An epidemiological study has shown that 4 months after the initial diagnosis only about 50% of subjects still had the same subtype of insomnia." Therefore a more general definition, such as that specified by the Diagnostic and
Statistical Manual of Mental Disorders (DSM), may be more useful in the clinical setting. Three diagnostic classifications for sleep disorders are in use: DSM-IV, ICD-10, and the International Classification of Sleep Disorders (ICSD). DSM-IV In DSM-IV, primary sleep disorders are described as sleep problems that cannot be accounted for by another mental disorder, by a general medical condition or by substance use or withdrawal." The primary sleep disorders are divided into the dyssomnias and the parasornnias. In the dyssomnias the predominant disturbance is in the amount, quality or timing of sleep; they include: Primary Insomnia, Primary Hypersomnia, Narcolepsy, Breathing-Related Sleep Disorder, and Circadian Rhythm Sleep Disorder. Parasomnias inlcude Nightmare Disorder, Sleep Terror Disorder and Sleep-walking Disorder. In this paper we describe a study we have carried out on a group of patients complaining of insomnia as defined by DSM-IV. A major advantage of the DSM-IV classification lies in its clinicallybased diagnostic criteria, and a structured interview has now been introduced (the Structured Interview for Sleep Disorders According to DSM-111-R) (SIS-D), which enhances diagnostic reliability." Unfortunately this questionnaire was not available at the time of our study. ICD-10 and ICSD The ICD-10 classification system (developed by the World Health Organization') includes sleep disorders of both nonorganic and organic origin; the former have explicit diagnostic criteria. The ICSD system subdivides the insomnias into numerous highly specific subtypes (sleep state misperception, idiopathic insomnia, inadequate sleep hygiene, delayed sleep phase syndrome, hypnotic- dependent insomnia, periodic limb movement disorder, etc.) and is mainly used as a research in~trument.'~
TREATMENTS IN CURRENT U S E Although many people complain of insomnia, it is thought that less than 20% of them ever discuss it with their doctors.' Many resort to ineffective or dangerous selftreatment regimens. Indeed the use of non-prescription drugs has surpassed that of prescription sedative-hypnotic drugs.14*15One survey found that of 700 people complaining of insomnia, 40% reported that they medicated themselves, but only 20% had ever used a prescription sleep aid. It was also found that 30% reported using alcohol, either alone or in combination with an over-thecounter (OTC) sleep aid.16Moreover, 66%report that they do not have an understanding of available treatments. Despite their popularity, little research has been carried out on OTC compounds. A Food and Drug Administration (FDA) drug review in the USA resulted in exclusion of all active ingredients in OTC sleep aids with the exception of two antihistamines, namely diphenhydramine hydrochloride and doxylamine s~ccinate.'~ Many of the other active
Int J Psych Clin Pract Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/25/14 For personal use only.
Assessment and treatment of insomnia
ingredients were shown to be either unsafe (toxic, teratogenic, carcinogenic) or ineffective. Side-effects of OTC sleep aids include dizziness, morning sedation, headache, nausea, blurred or double vision, impaired reaction times, constipation, dry mouth, tinnitus and palpitations." The combination of alcohol and these drugs may also result in additive drug effects.lg The rate of alcoholism among people with insomnia is twice that among good sleepers2' Many drugs, both prescription and non-prescription, affect sleep, and patients often do not connect the onset of insomnia with their medication. The list is long but some of the main such drugs are: alcohol, antihypertensives, antineoplastics, aspirin, fi-adrenoceptors, caffiene, corticosteroids, diuretics, ibuprofen, levadopa, thyroid hormone, nicotine, oral contraceptives, selective serotonin reuptake inhibitors (SSRIs), stimulants, theophylline and phenytoin.
A CASE CONTROL STUDY OF PATIENTS WITH PRIMARY INSOMNIA We have recently completed a study of patients with Primary Insomnia compared with matched controls. Our main aim was to find out whether patients with Primary Insomnia have a different pattern of secretion of melatonin from that of matched controls. The rationale for this was based on evidence that suggests that melatonin plays a role in the regulation of sleep. The results of the study have been published elsewhere." We include here a description of our group of patients with Primary Insomnia and two case studies.
PRIMARY INSOMNIA AS DEFINEDBY DSM-IV The predominant complaints are of difficulty in initiating or maintaining sleep, or of non-restorative sleep (sleep that is apparently adequate in amount, but leaves the person feeling unrested). The disturbance occurs for at least one month and is sufficiently severe to result in a complaint of significant changes in either daytime functioning or wellbeing, At the time of recruitment, DSM-IV was not available, so we used criteria based on DSM-III-R to make a diagnosis of Primary Insomnia. There is essentially no difference between the criteria for Primary Insomnia in DSM-III-R and DSM-IV. In order to make a diagnosis of Primary Insomnia, a thorough sleep history is essential. Polysomnography is not required for the routine evaluation of transient or chronic insomnia. However, when the cause of insomnia is uncertain, or when behavioural drug treatment is unsuccessful, polysomnography may be helpful. Polysomnography is indicated in the evaluation of suspected sleep-related breathing disorders and periodic limb movement disorder, which may contribute to a complaint of insomnia.22 We used polysomnography in our study, in order to make a reliable diagnosis for research purposes.
109
STUDY DESIGN Demographic details Inclusion criteria for patients were: male or female, aged between 40 and 70 years, with a DSM-III-R diagnosis of Primary Insmonia, with no current psychiatric or significant medical disorder, and not taking psychotropic medication. For controls, inclusion criteria were as for patients with Primary Insomnia, but with no current sleep problem. Ten male and ten female patients with Primary Insomnia (mean age 53.9 years, range 40-68 years) were matched for age and sex with 20 controls (mean age 54.7 years, range 40-69 years). Both patients and controls were either recruited through advertisements in local papers and local radio, or had previously taken part in studies or were known to colleagues. Approximately 200 people with insomnia responded to our advertisements over an 18month period, but most were excluded because they took medication (particularly beta blockers). All subjects were asked questions concerning their sleeping pattern and habits, and were screened for current and past psychiatric disorder using the Structural Clinical Interview for DSMIII-R (SCID). Each had a standard systematic medical questionnaire and physical examination. Each subject gave informed consent and details of the study were sent to each subject's general practitioner. The study was approved by the local ethics committee.
METHODS Assessment of sleep: subjective assessment At the initial interview, all subjects were asked the same questions about their sleeping pattern and related habits, and were asked to keep a diary for a week. The Epworth Sleepiness Scale23 was administered to all subjects. Objective assessment Polysomnography was carried out using ambulatory homebased equipment (Oxford Medilog 9000-11). Subjects were asked to come to the Research Unit in the late afternoon to have the sleep montage electrodes applied. [two electroencephalogram (EEG) channels (C,-A,, C,-A,), two electrooculogram (EOG) channels from the outer canthus of each eye referred to the mastoid, and submental electromyogram (EMG)]. Subjects retired and rose at their usual time. The records were analysed using the Oxford Medilog sleep stager (9200) and also visually edited. Two consecutive nights' sleep were recorded.
RESULTS The main demographic characteristics of patients and controls are shown in Table 1. Fewer of the patients than of the controls were in employment, and more were retired (non-significant difference). The characteristics of the sleep
Int J Psych Clin Pract Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/25/14 For personal use only.
110
AL Sharpley et al
disturbance described by the patient group are summarised in Table 2. Only some patients described initial insomnia or early morning waking, but all patients described difficulty in maintaining sleep. Most described insomnia on more than six nights a week. The mean duration of sleep disturbance was 18.3 years. The Epworth Sleepiness Scores were within the normal range for both the control and patient groups, and there was no significant difference between the two groups (i.e. the insomniacs were not suffering from excessive daytime sleepiness). Sleep hygiene was reasonably good in both groups (Tables 3 and 4). However, patients with insomnia were significantly more likely to have a daytime nap, and their reported alcohol consumption was higher. There was no difference between caffeine consumption in the two groups. Lifetime assessement of past psychiatric disorder (Table 5) showed that the patients with insomnia were signifi-
cantly more likely to have had a past psychiatric disorder. When the disorders are considered separately, patients with insomnia were more likely to have suffered from major depressive disorder and alcohol dependence (six individuals had more than one past diagnosis). Poly somnography The data followed a normal distribution, as tested by the Kolmogorov-Smirnov Goodness of Fit Test.
Comparison between first and second nights Firstly, analysis with t-tests for paired samples (2-tailed) was carried out between night 1 and night 2, for both the patients with insomnia and the control group. In the insomnia group, actual sleep time (AST) and % sleep efficiency (SE) were significantly increased (P=O.OOl and 0.003 respectively) and waking after sleep onset > 120 s (WASO) was significantly decreased (P=0.013) on night 2.
Table 1 Demographic data
Controls Gender 10 M, 10 F Age, years (mean, range) 53.9 (40-68) Marital status married 17 (85%) divorced 0 single 2 (10%) widowed 1 (5%) Employment employed 15 (75%) retired 5 (25%) unemployed 0
Table 3 Physical data
Patients
10 M, 10 F 54.7(40-69)
Controls Body Mass Index (BMI) 25.5f 1.0 weight (kglheight (m)* (mean& sem) 5.98f 1.39 Alcohol consumption, unitshKeek (mean f sem) Caffeine consumption, 5.5 f0.6 cupdday (mean fsem)
17 (85%) 1 (5%) 0 2 (10%) 11 (55%) 8 (40%) 1 (5%)
Patients
25.67f0.7 10.1f2.0* 4.9 0.8
*P 120 s were significantly increased (P < 0.01, P < 0.05) in the insomnia group compared with controls (Table 7).
SUMMARY OF RESULTS We were able to demonstrate significant differences in both descriptive and objective EEG data between those with Primary Insomnia and controls. The patients with insomnia reported much more difficulty in staying asleep (sleep maintenance) than with prolonged sleep onset latency (initial insomnia). This was borne out by the polysomno-
Table 4 Sleep hygiene data
Daytime naps Regular exercise In bed before midnight Arising before 9.00 am
Controls
Patients
9 (45%) 16 (80%) 19 (95%) 20 (100%)
15 (75%)* 12 (60%) 20 (100%) 20 (100%)
*P
International Journal of Psychiatry in Clinical Practice 1997 Volume I Pages 107- 1 1 7
107
Int J Psych Clin Pract Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/25/14 For personal use only.
Assessment and treatment of insomnia (including a case control study of patients with Primary Insomnia) ANN L SHARPLEY, MARY E J ATTENBURROW AND PHILIP J COWEN Psychopharmacology Research Unit, Littlemore Hospital, Oxford
Correspondence Address Dr A L Sharpley, Psychopharmacology Research Unit, Littlemore Hospital, Littlemore, Oxford OX4 4XN Tel 01865 223130 Fax 01865 775 212
Received 27 January 1997; accepted for publication 9 April 1997
Insomnia is a subjective term describing the perception of disturbed or inadequate sleep. Causes include medical diseases, psychiatric disorders, drugs, behavioural factors, circadian dysrhythmias and primary sleep disorders. Insomnia is common, affecting approximately one-third of the total population, and of these about 10%consider it a chronic problem. Insomnia is more common infemales and increases with age. Many people with insomnia resort to ineffective or dangerous self-treatment regimens and the combination of alcohol with non-prescription drugs is common. We have carried out a study on 20 patients with Primary Insomnia and were able to demonstrate significant dgerences in both descriptive and objective EEG data between those with Primary Insomnia and controls. Careful evaluation of the sleep problem and accurate diagnosis are essential in order to choose the right treatment for an individual patient. When a specific problem is identified (psychiatric, physical, behavioural), then the underlying cause needs to be treated. Insomnia can be treated by either non-pharmacological or pharmacological intervention, and often both are used simultaneously. It is recommended that hypnotic treatments should be used for no more than one month. (Int J Psych Clin Pruct 1997; 1:107- 117)
Keywords primnry insomnia treatment sleep hygiene
INTRODUCTION
T
he word ‘insomnia’ comes from Latin and means ‘no sleep’. The complaint is subjective, and the word describes the perception of disturbed or inadequate sleep-i.e. sleep that is difficult to initiate or maintain, or that is non-refreshing or non-restorative-and is usually associated with changes in daytime functioning and well-being. Causes include medical diseases, psychiatric disorders, drugs both prescribed and non-prescribed (including alcohol), behavioural factors, circadian dysrhythmias and primary sleep disorders. Conversely, a broad definition of a ‘good night’s sleep’ is that a person takes less than 30 minutes to fall asleep, maintains sleep for 6-8 hours with only a couple of brief awakenings and feels well-rested and refreshed upon waking.
assessment hypnotics
Insomnia can cause significant deterioration in the quality of life, including difficulties with concentration, memory, ability to accomplish daily tasks, and enjoyment of interpersonal relationships. The ability to cope with minor irritations is also significantly impaired. It has been reported that 10%of people who complain of insomnia fall asleep while visiting friends.’
MOTORVEHICLEACCIDENTS Between 1% and 10% of motor vehicle accidents are directly related to sleepines2 People suffering from insomnia are more than twice as likely as good sleepers to report vehicle accidents in which fatigue was a factor. The Stanford Sleep Disorders Clinic statistics show that 15-45% of all patients suffering from sleep apnoea and 12-30% suffering from narcolepsy have had at least one
108
AL Sharpley et al
Int J Psych Clin Pract Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/25/14 For personal use only.
accident related to sleepiness; 2 -8Oh of patients with insomnia also admitted at least one accident related to sleepiness. Considering the number of people suffering from insomnia (rather than from sleep apnoea or narcolepsy), the impact of insomnia on accident statistics plus the economic cost of such accidents is seen to be It is not surprising that over 50% of ~onsiderable.~ accidents occur at night when the propensity to sleep is at its peak.4 It appears that sleepiness is generally a very underrated factor in accidents.
EPIDEMIOLOGY Insomnia is common. According to various epidemiological studies in the USA, there is general agreement that approximately one-third of the total population suffers from insomnia, and of these about 10% consider it a chronic A recent WHO collaborative study in 15 different countries has shown a similar pattern of insomnia and, like the US studies, found that insomnia is more common in females and increases with age.5 The tendency to seek medical advice increases with age, as does the propensity to take daytime naps. Indeed, it is thought that half of the population over 65 years of age suffer from chronic sleep disturbances.' The WHO study found that 51% of people with an insomnia complaint also had a welldefined ICD-109 mental disorder such as depression, anxiety or alcohol problems.
CLASSIFICATION OF INSOMNIAS The longer insomnia lasts, the more complex its management becomes. It can be divided into three groups according to duration. 1. Transient insomnia lasts for a few days. Most people will suffer from this from time to time, and it is often associated with a specific event such as examination stress, jet lag or environment. Sleep-promoting medication are appropriate and can be used prophylactically. 2. Short-term insomnia lasts for a matter of weeks, and is usually associated with stress or medical illness. 3 . Chronic insomnia lasts for months or perhaps years, and has multiple contributing factors. In clinics specializing in sleep disorders, approximately 15%25% of individuals with chronic insomnia are diagnosed as having Primary Insomnia."
Traditionally, insomnia has been classified as sleeponset insomnia, sleep-maintenance insomnia and early morning awakening. However, this classification is only useful if the type of insomnia remains stable over time. An epidemiological study has shown that 4 months after the initial diagnosis only about 50% of subjects still had the same subtype of insomnia." Therefore a more general definition, such as that specified by the Diagnostic and
Statistical Manual of Mental Disorders (DSM), may be more useful in the clinical setting. Three diagnostic classifications for sleep disorders are in use: DSM-IV, ICD-10, and the International Classification of Sleep Disorders (ICSD). DSM-IV In DSM-IV, primary sleep disorders are described as sleep problems that cannot be accounted for by another mental disorder, by a general medical condition or by substance use or withdrawal." The primary sleep disorders are divided into the dyssomnias and the parasornnias. In the dyssomnias the predominant disturbance is in the amount, quality or timing of sleep; they include: Primary Insomnia, Primary Hypersomnia, Narcolepsy, Breathing-Related Sleep Disorder, and Circadian Rhythm Sleep Disorder. Parasomnias inlcude Nightmare Disorder, Sleep Terror Disorder and Sleep-walking Disorder. In this paper we describe a study we have carried out on a group of patients complaining of insomnia as defined by DSM-IV. A major advantage of the DSM-IV classification lies in its clinicallybased diagnostic criteria, and a structured interview has now been introduced (the Structured Interview for Sleep Disorders According to DSM-111-R) (SIS-D), which enhances diagnostic reliability." Unfortunately this questionnaire was not available at the time of our study. ICD-10 and ICSD The ICD-10 classification system (developed by the World Health Organization') includes sleep disorders of both nonorganic and organic origin; the former have explicit diagnostic criteria. The ICSD system subdivides the insomnias into numerous highly specific subtypes (sleep state misperception, idiopathic insomnia, inadequate sleep hygiene, delayed sleep phase syndrome, hypnotic- dependent insomnia, periodic limb movement disorder, etc.) and is mainly used as a research in~trument.'~
TREATMENTS IN CURRENT U S E Although many people complain of insomnia, it is thought that less than 20% of them ever discuss it with their doctors.' Many resort to ineffective or dangerous selftreatment regimens. Indeed the use of non-prescription drugs has surpassed that of prescription sedative-hypnotic drugs.14*15One survey found that of 700 people complaining of insomnia, 40% reported that they medicated themselves, but only 20% had ever used a prescription sleep aid. It was also found that 30% reported using alcohol, either alone or in combination with an over-thecounter (OTC) sleep aid.16Moreover, 66%report that they do not have an understanding of available treatments. Despite their popularity, little research has been carried out on OTC compounds. A Food and Drug Administration (FDA) drug review in the USA resulted in exclusion of all active ingredients in OTC sleep aids with the exception of two antihistamines, namely diphenhydramine hydrochloride and doxylamine s~ccinate.'~ Many of the other active
Int J Psych Clin Pract Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/25/14 For personal use only.
Assessment and treatment of insomnia
ingredients were shown to be either unsafe (toxic, teratogenic, carcinogenic) or ineffective. Side-effects of OTC sleep aids include dizziness, morning sedation, headache, nausea, blurred or double vision, impaired reaction times, constipation, dry mouth, tinnitus and palpitations." The combination of alcohol and these drugs may also result in additive drug effects.lg The rate of alcoholism among people with insomnia is twice that among good sleepers2' Many drugs, both prescription and non-prescription, affect sleep, and patients often do not connect the onset of insomnia with their medication. The list is long but some of the main such drugs are: alcohol, antihypertensives, antineoplastics, aspirin, fi-adrenoceptors, caffiene, corticosteroids, diuretics, ibuprofen, levadopa, thyroid hormone, nicotine, oral contraceptives, selective serotonin reuptake inhibitors (SSRIs), stimulants, theophylline and phenytoin.
A CASE CONTROL STUDY OF PATIENTS WITH PRIMARY INSOMNIA We have recently completed a study of patients with Primary Insomnia compared with matched controls. Our main aim was to find out whether patients with Primary Insomnia have a different pattern of secretion of melatonin from that of matched controls. The rationale for this was based on evidence that suggests that melatonin plays a role in the regulation of sleep. The results of the study have been published elsewhere." We include here a description of our group of patients with Primary Insomnia and two case studies.
PRIMARY INSOMNIA AS DEFINEDBY DSM-IV The predominant complaints are of difficulty in initiating or maintaining sleep, or of non-restorative sleep (sleep that is apparently adequate in amount, but leaves the person feeling unrested). The disturbance occurs for at least one month and is sufficiently severe to result in a complaint of significant changes in either daytime functioning or wellbeing, At the time of recruitment, DSM-IV was not available, so we used criteria based on DSM-III-R to make a diagnosis of Primary Insomnia. There is essentially no difference between the criteria for Primary Insomnia in DSM-III-R and DSM-IV. In order to make a diagnosis of Primary Insomnia, a thorough sleep history is essential. Polysomnography is not required for the routine evaluation of transient or chronic insomnia. However, when the cause of insomnia is uncertain, or when behavioural drug treatment is unsuccessful, polysomnography may be helpful. Polysomnography is indicated in the evaluation of suspected sleep-related breathing disorders and periodic limb movement disorder, which may contribute to a complaint of insomnia.22 We used polysomnography in our study, in order to make a reliable diagnosis for research purposes.
109
STUDY DESIGN Demographic details Inclusion criteria for patients were: male or female, aged between 40 and 70 years, with a DSM-III-R diagnosis of Primary Insmonia, with no current psychiatric or significant medical disorder, and not taking psychotropic medication. For controls, inclusion criteria were as for patients with Primary Insomnia, but with no current sleep problem. Ten male and ten female patients with Primary Insomnia (mean age 53.9 years, range 40-68 years) were matched for age and sex with 20 controls (mean age 54.7 years, range 40-69 years). Both patients and controls were either recruited through advertisements in local papers and local radio, or had previously taken part in studies or were known to colleagues. Approximately 200 people with insomnia responded to our advertisements over an 18month period, but most were excluded because they took medication (particularly beta blockers). All subjects were asked questions concerning their sleeping pattern and habits, and were screened for current and past psychiatric disorder using the Structural Clinical Interview for DSMIII-R (SCID). Each had a standard systematic medical questionnaire and physical examination. Each subject gave informed consent and details of the study were sent to each subject's general practitioner. The study was approved by the local ethics committee.
METHODS Assessment of sleep: subjective assessment At the initial interview, all subjects were asked the same questions about their sleeping pattern and related habits, and were asked to keep a diary for a week. The Epworth Sleepiness Scale23 was administered to all subjects. Objective assessment Polysomnography was carried out using ambulatory homebased equipment (Oxford Medilog 9000-11). Subjects were asked to come to the Research Unit in the late afternoon to have the sleep montage electrodes applied. [two electroencephalogram (EEG) channels (C,-A,, C,-A,), two electrooculogram (EOG) channels from the outer canthus of each eye referred to the mastoid, and submental electromyogram (EMG)]. Subjects retired and rose at their usual time. The records were analysed using the Oxford Medilog sleep stager (9200) and also visually edited. Two consecutive nights' sleep were recorded.
RESULTS The main demographic characteristics of patients and controls are shown in Table 1. Fewer of the patients than of the controls were in employment, and more were retired (non-significant difference). The characteristics of the sleep
Int J Psych Clin Pract Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/25/14 For personal use only.
110
AL Sharpley et al
disturbance described by the patient group are summarised in Table 2. Only some patients described initial insomnia or early morning waking, but all patients described difficulty in maintaining sleep. Most described insomnia on more than six nights a week. The mean duration of sleep disturbance was 18.3 years. The Epworth Sleepiness Scores were within the normal range for both the control and patient groups, and there was no significant difference between the two groups (i.e. the insomniacs were not suffering from excessive daytime sleepiness). Sleep hygiene was reasonably good in both groups (Tables 3 and 4). However, patients with insomnia were significantly more likely to have a daytime nap, and their reported alcohol consumption was higher. There was no difference between caffeine consumption in the two groups. Lifetime assessement of past psychiatric disorder (Table 5) showed that the patients with insomnia were signifi-
cantly more likely to have had a past psychiatric disorder. When the disorders are considered separately, patients with insomnia were more likely to have suffered from major depressive disorder and alcohol dependence (six individuals had more than one past diagnosis). Poly somnography The data followed a normal distribution, as tested by the Kolmogorov-Smirnov Goodness of Fit Test.
Comparison between first and second nights Firstly, analysis with t-tests for paired samples (2-tailed) was carried out between night 1 and night 2, for both the patients with insomnia and the control group. In the insomnia group, actual sleep time (AST) and % sleep efficiency (SE) were significantly increased (P=O.OOl and 0.003 respectively) and waking after sleep onset > 120 s (WASO) was significantly decreased (P=0.013) on night 2.
Table 1 Demographic data
Controls Gender 10 M, 10 F Age, years (mean, range) 53.9 (40-68) Marital status married 17 (85%) divorced 0 single 2 (10%) widowed 1 (5%) Employment employed 15 (75%) retired 5 (25%) unemployed 0
Table 3 Physical data
Patients
10 M, 10 F 54.7(40-69)
Controls Body Mass Index (BMI) 25.5f 1.0 weight (kglheight (m)* (mean& sem) 5.98f 1.39 Alcohol consumption, unitshKeek (mean f sem) Caffeine consumption, 5.5 f0.6 cupdday (mean fsem)
17 (85%) 1 (5%) 0 2 (10%) 11 (55%) 8 (40%) 1 (5%)
Patients
25.67f0.7 10.1f2.0* 4.9 0.8
*P 120 s were significantly increased (P < 0.01, P < 0.05) in the insomnia group compared with controls (Table 7).
SUMMARY OF RESULTS We were able to demonstrate significant differences in both descriptive and objective EEG data between those with Primary Insomnia and controls. The patients with insomnia reported much more difficulty in staying asleep (sleep maintenance) than with prolonged sleep onset latency (initial insomnia). This was borne out by the polysomno-
Table 4 Sleep hygiene data
Daytime naps Regular exercise In bed before midnight Arising before 9.00 am
Controls
Patients
9 (45%) 16 (80%) 19 (95%) 20 (100%)
15 (75%)* 12 (60%) 20 (100%) 20 (100%)
*P
