Siu-Ping Lam

The Chinese University of Hong Kong, Hong Kong, Hong Kong

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Publications (10)47.76 Total impact

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    ABSTRACT: Context: The association between insomnia disorder and hypothalamic-pituitary-adrenal (HPA) axis needs to be explored across both adults and adolescents. Objectives: To investigate the associations of HPA axis (via serial salivary cortisol) with insomnia disorder, subjective and objective sleep quality in a community-based study. Design and setting: Community-based case-control family study. Participants: 205 adolescents (14.2 ± 2.8 years old, 51.7% females, and 57 with insomnia) and nsouring weekends in adolescents. ated with short sleep duration during weekdays and late bedtime during weekends in adolesfcen 244 adults (46.4 ± 4.1 years old, 52.8% females, and 69 with insomnia) Intervention: None. Main Outcome Measures: Diagnostic interview for assessment of insomnia disorder, 3-day actigraphy and sleep diary, and serial salivary cortisol measurement. Results: Adults with insomnia had a significantly greater cortisol awakening response reference to increase (CARi) but a comparable cortisol awakening response reference to ground (CARg) and a comparable cortisol level during afternoon and evening when compared with non-insomniac adults. The association between insomnia disorder and larger CARi was also found in adolescents at late/post puberty but not in pre/early pubertal adolescents. There was an interaction effect between sex and insomnia disorder on CARi level with adult females having larger CARi than adult males. Among subjects with insomnia disorder, those with lower subjective sleep efficiency had higher cortisol levels at late evening (10 pm) in both adults and adolescents. Conclusions: Our study suggests that a series of insomniac indices at both syndromal and symptomatic levels including clinical diagnosis and poor sleep quality are associated with dysfunction of HPA axis. The association between insomnia and increased CARi emerges at late puberty and the sex difference in this association occurs in adulthood but not in adolescence.
    The Journal of Clinical Endocrinology and Metabolism 03/2014; 99(6):jc20133728. DOI:10.1210/jc.2013-3728 · 6.31 Impact Factor
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    ABSTRACT: Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by an absence of normal skeletal muscle atonia during REM sleep and clinical features of disturbing dreams and dream enacting behaviors. Hence, the common sequelae are sleep-related injury and violence to both patients and bed-partners. Although polysomnographic evidence of REM sleep without atonia, is regarded as a gold standard for the confirmation of RBD diagnosis, polysomnography is both time and resource consuming. In order to facilitate early detection and clinical management, developing a convenient and suitable screening tool to identify individuals at risk of RBD would enable physicians to prioritize those who may require timely assessment and clinical intervention. In addition, the longitudinal course of RBD and its prognostic implication in predicting neurodegenerative disorders may suggest a potential therapeutic window for early preventive management of underlying progress of neurodegeneration. The availability of suitable RBD scales may facilitate timely assessment, accurate diagnosis and monitoring of disease progress of RBD. The present paper summarized recent research on the development of screening tools of RBD, their psychometric properties, and the applications of these questionnaires.
    Sleep Medicine 11/2012; DOI:10.1016/j.sleep.2012.09.008 · 3.10 Impact Factor
  • Jihui Zhang, Siu-Ping Lam, Yun-Kwok Wing
    Sleep Medicine 09/2012; 13(9):1113-4. DOI:10.1016/j.sleep.2012.08.006 · 3.10 Impact Factor
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    ABSTRACT: OBJECTIVES: REM sleep behavior disorder (RBD) has been increasingly reported in patients with psychiatric disorders (pRBD). Although a close association with the usage of psychotropics has been postulated, it remains elusive whether psychotropics are the only causative factor of RBD symptoms in psychiatric populations. Moreover, there is limited literature documenting and quantifying the clinical and polysomnographic features in this population. METHODS: A case-control study comparing the clinical and polysomnographic features of 31 pRBD patients with: (1) Age-, sex-, and psychiatric diagnoses-matched controls; and (2) Typical idiopathic RBD (tRBD) patients. RESULTS: Despite being prescribed with similar psychotropics, pRBD patients had more dream-enacting behaviors (p<0.01), sleep-related injuries (p<0.01), and nightmares (p<0.01) than the psychiatric controls. pRBD patients were younger with more females, but they had comparable sleep-related injuries to tRBD. Both tRBD and pRBD had more REM-related muscle activity than controls (p<0.01) and the effect remained significant after adjusting for age, gender, and use of antidepressants. CONCLUSIONS: Our study suggests that pRBD had comparable clinical features and consequences to those of tRBD. The occurrence of RBD symptoms in these patients may be related to a constellation of factors, including individual predisposition, depressive illness, antidepressants, and other clinical factors. Given the association of RBD and neurodegeneration in tRBD, further prospective follow-up of these patients is warranted.
    Sleep Medicine 07/2012; DOI:10.1016/j.sleep.2012.05.016 · 3.10 Impact Factor
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    ABSTRACT: There is a dearth of data on the longitudinal course and outcome of non-restorative sleep (NRS). A total of 2291 middle-aged adults (mean [SD]=46.3 [5.1] years old, 50.0% males at follow-up) were recruited into a 5-year follow-up study. NRS was defined as morning unfreshness after getting up ≥ 3 times/week over the past 12 months. Socio-demographics, other concurrent sleep complaints, and daytime symptoms were measured at baseline. Chronic medical problems in the past one year were additionally assessed at follow up. Several sleep problems (including other insomnia subtypes, snoring, and nightmares) and daytime symptoms were strongly associated with NRS at baseline. NRS had considerable persistence (31.9%), partial remission (22.7%), and incidence rate (5.2%). New incidence of NRS was predicted by female gender (AOR=1.67), preferring not to get up in the morning (AOR=1.96), fatigue (AOR=2.18), and short sleep duration (AOR=1.87), whereas persistence of NRS was predicted by difficulty initiating sleep (AOR=2.36). In the fully adjusted models, baseline NRS was significantly associated with multiple medical disorders at follow-up, including frequent allergic rhinitis (AOR=1.62) and laryngopharyngitis (AOR=2.47), diabetes mellitus (AOR=2.63), gastroesophageal reflux disease (AOR=2.03), eye problems (AOR=2.45), eczema (AOR=2.18), and poor mental health (AOR=1.68). The persistent course and independent association of NRS with adverse medical and mental outcomes argue for a distinct nosological status and the need for rigorous medical attention.
    Sleep Medicine 03/2012; 13(6):570-6. DOI:10.1016/j.sleep.2011.12.012 · 3.10 Impact Factor
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    ABSTRACT: This study investigated the sex differences, and the shared genetic and environmental factors underlying the associations of sleep disturbances (insomnia and sleep quality) with pain and somatic symptoms in both adolescents and middle-aged adults. We recruited 259 adolescents (69 with current insomnia) and their parents (256 middle-aged adults, 78 with current insomnia). Insomnia severity and sleep quality were measured by the Insomnia Severity Inventory (ISI) and Pittsburgh Sleep Quality Index (PSQI), respectively. Pain and somatic symptoms were measured by the Somatic Symptom Inventory and Visual Analogue Scale for overall pain. Subjects with insomnia scored higher on all measures of pain and somatic symptoms than non-insomnia patients, in both adolescents and adults (P<.001). Both pain and somatic measures were associated with ISI and PSQI scores after controlling for age, sex, depressive and anxiety symptoms. There was an interaction effect between insomnia and female sex on pain and somatic symptoms (P<.05), especially in adults. Pain and somatic symptoms ran in family with moderate heritability (range h(2)=0.15-0.42). The phenotypic associations of ISI and PSQI with pain and somatic measures were both contributed by genetic (range p(G)=0.41-0.96) and environmental (range p(E)=0.27-0.40) factors with a major genetic contribution. In summary, insomnia and poor sleep quality are closely associated with pain and somatic symptoms. Insomnia seems to modulate the sex differences in pain and somatic symptoms, especially in the adult population. A shared genetic predisposition might underlie the associations of insomnia and sleep quality with pain and somatic symptoms.
    Pain 03/2012; 153(3):666-73. DOI:10.1016/j.pain.2011.12.003 · 5.84 Impact Factor
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    ABSTRACT: To determine the familial aggregation of narcolepsy from perspectives of clinical symptomatology, polysomnographic data, and human leukocyte antigen (HLA) typing. This was a Family study at the University-affiliated hospital. The participants were narcolepsy probands and their first degree relatives, and, also, age and sex matched unrelated healthy controls. Interventions were not applicable. All study subjects underwent structured interviews, overnight polysomnography followed by a multiple sleep latency test (MSLT), and HLA typing. Altogether, 33 probands and 81 first degree relatives (response rate 65%) were recruited. Among the relatives, 12.3% were diagnosed with narcolepsy and 39.5% had narcolepsy spectrum as defined by unexplained abnormal MSLT (shortened MSL and SOREMP) results. The relative risk of narcolepsy in first degree relatives was 361.8. Familial aggregation of narcolepsy symptoms, excessive daytime sleepiness, HLA status, abnormal MSLT, and nocturnal polysomnographic findings were observed. The familial risk of narcolepsy among first degree relatives is much higher than previously reported. There exists a spectrum of narcolepsy features among relatives, ranging from full clinical tetrads to asymptomatic abnormal MSLT findings.
    Sleep Medicine 12/2011; 12(10):947-51. DOI:10.1016/j.sleep.2011.05.007 · 3.10 Impact Factor
  • Sleep Medicine 09/2011; 12:S7-S8. DOI:10.1016/S1389-9457(11)70025-9 · 3.10 Impact Factor
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    ABSTRACT: Short-term follow-up studies of severe acute respiratory syndrome (SARS) survivors suggested that their physical conditions continuously improved in the first year but that their mental health did not. We investigated long-term psychiatric morbidities and chronic fatigue among SARS survivors. All SARS survivors from the hospitals of a local region in Hong Kong were assessed by a constellation of psychometric questionnaires and a semistructured clinical interview for the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) to determine the presence of psychiatric disorders and chronic fatigue problems. Of 369 SARS survivors, 233 (63.1%) participated in the study (mean period of time after SARS, 41.3 months). Over 40% of the respondents had active psychiatric illnesses, 40.3% reported a chronic fatigue problem, and 27.1% met the modified 1994 Centers for Disease Control and Prevention criteria for chronic fatigue syndrome. Logistic regression analysis suggested that being a health care worker at the time of SARS infection (odds ratio [OR], 3.24; 95% confidence interval [CI], 1.12- 9.39; P = .03), being unemployed at follow-up (OR, 4.71; 95% CI, 1.50-14.78; P = .008), having a perception of social stigmatization (OR, 3.03; 95% CI, 1.20-7.60; P = .02), and having applied to the SARS survivors' fund (OR, 2.92; 95% CI, 1.18-7.22; P = .02) were associated with an increased risk of psychiatric morbidities at follow-up, whereas application to the SARS survivors' fund (OR, 2.64; 95% CI, 1.07-6.51; P = .04) was associated with increased risk of chronic fatigue problems. Psychiatric morbidities and chronic fatigue persisted and continued to be clinically significant among the survivors at the 4-year follow-up. Optimization of the treatment of mental health morbidities by a multidisciplinary approach with a view for long-term rehabilitation, especially targeting psychiatric and fatigue problems and functional and occupational rehabilitation, would be needed.
    Archives of internal medicine 12/2009; 169(22):2142-7. DOI:10.1001/archinternmed.2009.384 · 13.25 Impact Factor
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    ABSTRACT: In contrast to the 'benign and self-limiting nature' of childhood sleepwalking, some population and case studies have suggested that adult sleepwalking is more likely to be associated with psychopathology and psychotropic medications. There is a paucity, however, of systematic study in adult psychiatric populations, and the aim of the present study was therefore to compare the impact of psychopathology and medication usage on sleepwalking with reference to age of onset. Clinical characteristics, sleep symptoms, psychiatric diagnosis and psychotropic usage in 66 childhood- and adult-onset sleepwalkers as identified from a psychiatric clinic, were studied. There was a higher proportion of adult-onset sleepwalking in the psychiatric population. In comparison with childhood-onset sleepwalkers, adult-onset sleepwalkers had higher peak frequency of attacks and a high comorbidity with sleep-related eating features. Factors including frequent insomnia (odds ratio (OR) = 5.39, 95% confidence interval (CI) = 1.58-18.40, p = 0.007) and lifetime usage of regular zolpidem (OR = 5.58, 95%CI = 1.65-18.84, p < 0.006) were associated with a higher risk of adult-onset sleepwalking. Adult-onset sleepwalking in a psychiatric sample has unique clinical characteristics and specific risk factors. These patients were more likely to present with sleep-related eating features, comorbid insomnia, had and lifetime usage of non-benzodiazepine hypnotics, especially zolpidem. A heightened awareness of the presence of sleepwalking and their associated risk factors among the adult psychiatric population is needed.
    Australian and New Zealand Journal of Psychiatry 05/2009; 43(5):426-30. DOI:10.1080/00048670902817703 · 3.77 Impact Factor