Hi, my name is Dr. Christopher Drake. I'm a bioscientific staff investigator at Henry Ford Hospital in Detroit, Michigan. I'm going to be talking to you today about insomnia, its causes, and consequences. So, the scientific attitudes regarding insomnia as a condition have really evolved over the past several decades. And we see here data from the NIH Consensus Conferences, which have occurred one in 1983 and one in 2005, surrounding the pathophysiology and treatment as well as other aspects of insomnia. And in 1983, we can see insomnia was thought of as a symptom rather than a primary disorder. And as such, the treatment for insomnia is really focused on the underlying problem that was assumed to be the cause of the sleep disturbance. In addition, treatment really focused on very short-term therapeutic interventions. But, more recently in 2005 during the NIH Consensus Conference, insomnia was really conceptualized. And this attitude has evolved even since then, to typically be understood as a condition which often occurs in comorbidity with other disorders. For example, chronic insomnia exists and merits treatment in its own right. It is in fact, a disorder, insomnia disorder. Which now is utilized in terms of treatments, which may last much longer in terms of the therapeutic intervention overall. For example, there is really no longer a short-term restriction on hypnotic use, and other behavioral treatments have been incorporated as well that will help patients maintain sleep appropriately over many, many years in conjunction with the treatments that are available. Insomnia disorder is now conceptualized as a predominant complaint of dissatisfaction with sleep quantity or quality, associated with one or more of the following symptoms: either difficulty initiating sleep, having trouble falling asleep initially, or difficulty maintaining sleep, waking up in the middle of the night and having a great deal of difficulty falling back to sleep, and finally, early morning awakenings with an inability to return to sleep. In addition to these nocturnal symptoms, the sleep disturbance is causing clinically significant distress, or impairment in social, occupational, academic, behavioral, or other important areas of functioning. And that sleep difficulty occurs at least three nights per week, and is present for at least three months. The sleep difficulty also occurs despite an adequate opportunity for sleep. And we're going to talk a little bit more about why that is different than what we normally think of as sleep deprivation. In addition, the insomnia should not be better explained by or does not occur exclusively during the course of another sleep-wake disorder such as, obstructive sleep apnea, or restless leg syndrome, or other sleep disorders. The insomnia should also not be attributable to the physiological effects of a substance, such as a drug of abuse or potentially a medication. In addition, coexisting medical disorders and medical conditions, are not able to adequately explain the predominant complaint of insomnia. When we look at the prevalence of insomnia in terms of the epidemiological data that's available, there are a wealth of studies out there which show the prevalence of insomnia symptoms is quite high. In fact, upwards of 40 to 50% of individuals in the general population will report some difficulty with sleep disturbances, a symptom over the course of their lives certainly. But when we really think about insomnia criteria, the criteria we just went over, insomnia symptoms, those nocturnal sleep disturbance symptoms which occur, in addition or in combination with some daytime consequences, the diagnosis of insomnia is probably somewhere between 6 and 15%. Although some studies show insomnia disorder prevalence being closer to 20%. There are a number of risk factors for insomnia. They include gender. And so women are at much greater risk for developing insomnia. We are also at increased risk for insomnia as we age, particularly due to some of the comorbidities that are also associated with insomnia. These can be medical illnesses, especially respiratory, chronic pain, and neurological disorders, but also include psychiatric illnesses such as depression and depressive symptoms. Certainly lower socioeconomic status is associated with insomnia, which may be also a reason for an increased rate of insomnia in African-Americans relative to several other races. And of course, stress can be a component of insomnia along with changing work schedules. What's very interesting is recently there have been a number of studies which point to a genetic basis underlying insomnia, and we're going to talk a little bit more about that. What we do not know although we do have information on the heritability of insomnia overall, we don't have information specifically about the particular genes that may in fact be involved with this disorder. As we can see here, going over some of those risk factors, insomnia increases with age. This is an aspect of insomnia, which is specifically related to the nocturnal symptoms. And I'm going to focus a little bit upon that in a moment. In terms of the daytime impairment, there is not a big increase with age. In fact, as we age, despite sleep disturbance becoming more prevalent, the degree of daytime impairment caused by this nocturnal sleep disturbance actually goes down. But what we can see with regard to the nocturnal symptoms, this is a graph showing the latency to sleep or how long it takes to fall asleep in minutes, in relation to age. These are a number of studies which have been done over the years, and as we can see, there's really not a strong relationship between the time it takes one to fall asleep and age. The specific pattern of sleep disturbance that increases with age are nocturnal awakenings or what we call sleep efficiency. And on the top graph, we can see sleep efficiency measured in percentage of time one is asleep during a given amount of time in bed clearly goes down with age. And we can see very disrupted sleep occurring in the bottom graph as age increases, particularly in the decades after 70 or so years old. In terms of the DSM-IV diagnosis of insomnia, there are certainly a number of disorders that are, again, comorbid with insomnia. In fact, approximately 84% of insomnia is comorbid with other disorders. These can include disorders such as depression, medical disorders, anxiety disorders, and other psychiatric conditions, and also no disorders at all. But, what we call primary insomnia is really insomnia that has not been identified to be associated with a specific identified precipitating event or condition. This is insomnia which is thought of as primary. One other aspect of insomnia that's important to address is the chronicity of the disorder. In fact, this study from 2001 showed that over 10 years, a full 44% of individuals will continue to have insomnia over this time period. That's a critically important point, because the chronicity of this disorder may have an impact on some of the consequences, which we're going to talk about next.
