Sleep dysfunction is common among patients with Parkinson's disease and occurs in approximately two thirds of patients. The problems range from nocturnal issues such as difficulty with sleep initiation, sleep fragmentation, disturbance of circadian rhythm, and rapid eye movement sleep behavior disorder, to daytime problems such as excessive daytime sleepiness. Frequent nighttime awakening and sleep disruption are the most common sleep problems in Parkinson's disease. Dopamine plays an important role in maintaining wakefulness. To improve sleep in Parkinson's disease, it is important to achieve the critical balance of adequate dopaminergic therapy and control of symptoms. Increased dopaminergic agents can cause dyskinesias and painful dystonia, and undertreatment can cause nighttime akinesia, rigidity, and worse quality of sleep. Other nondopaminergic drugs commonly used in Parkinson's disease can also affect sleep. In patients with advanced Parkinson's disease, deep brain stimulation of the subthalamic nucleus has a favorable impact on sleep quality and sleep architecture.

Insomnia is an extremely prevalent condition, affecting large segments of the population. There is a broad spectrum of risk factors for this disorder, most of which are various types of social, economic, or interpersonal stressors. Risk factors include age, female gender (especially post- and perimenopausal women), divorce/separation/widowhood, psychiatric illness (mood and anxiety disorders), medical conditions, cigarette smoking, alcohol consumption, coffee consumption, and certain prescription drugs. It is important to recognize that the symptom of insomnia (ie, disturbed or poor quality sleep) may be due to the presence of another primary sleep disorder, such as restless legs syndrome, periodic limb movements in sleep, or sleep apnea.

In 2004, more people died in Europe from suicide than from road accidents. The lifetime prevalence of major depression is 20% for women and 10% for men. Depression is a leading cause of disability and decreased quality of life. In spite of this, numerous studies have shown that only ~50% of depressed patients are recognized as such in primary care. In a recent international survey of everyday management of depression we observed that only ~15% of patients became symptom-free following treatment. In spite of this low level of remission primary care physicians and psychiatrist only rarely increased the dose of antidepressant or switched to another medication as unanimously recommended by different guidelines. Numerous studies have demonstrated the importance of maintaining treatment for ≥6 months after remission is obtained in order to prevent relapse and recurrence. However, a recent study reported that only 19% of a cohort of patients in primary care continued treatment for 6 months as recommended. Antidepressants can be very effective but only when used correctly at adequate doses and for a sufficient duration. Although new improved antidepressants are obviously desirable, a greater recognition of depression and its treatment by the correct use of currently available antidepressant drugs could greatly improve the management of this major public health problem.

When levodopa (L-dopa) is administered intravenously to patients with severe Parkinson's disease, a therapeutic response may be seen within a 1/2 hour. However, when the drug is administered orally in lower doses to less disabled patients, a delay of 1–2 weeks often occurs before motor deficits start to improve. Recent data from the Early versus Late Levodopa study suggest that maximum improvement at a fixed dosage may take ≤3 months to develop. A nonspecific feeling of well-being and reduced tiredness are often the first benefits to occur, followed by greater alacrity and less stiffness. Rest tremor is slower to improve, but may eventually disappear altogether and remain well controlled throughout the rest of the course of the malady. Gait, balance, and speech may also improve, but the effect is usually more modest and a decline is common after several years of sustained treatment.

Until recently, little was known about the epidemiology of attention-deficit/hyperactivity disorder (ADHD) in adults. Bottom-up studies following children with ADHD into adolescence had shown variable rates of persistence, some of which depended on the definitions used. The traditional diagnosis was complicated by the introduction of the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, which stated that ADHD could be diagnosed with inattentive symptoms alone. This resulted in diagnostic inconsistency as earlier investigations demanded the presence of hyperactivity while others did not. Diagnosis also depended on the site, the cohort, whether interviews versus rating scales were employed, and whether the subject or their parent were the source of information.

There are several important issues regarding the manner in which medications are tested prior to their release and monitored after approval that must be appreciated in considering issues related to cardiovascular safety of medication treatments for attention-deficit/hyperactivity disorder (ADHD) in adults. First, patients treated in clinical trials are not necessarily representative of those seen in practice settings, as specific inclusion/exclusion criteria in studies limit a variety of psychiatric, medical, and social factors that could potentially introduce confounds related to the collection and/or interpretation of efficacy, tolerability, and safety data. However, many of these factors are present in patients treated in clinical practice. In addition, the manner in which medications are administered in clinical trials does not necessarily replicate the way they are used in the community. Often, there are differences in titration schemes and dosing options. Also, in clinical trials, drugs are rarely studied in combination, although they are often used in this manner in practice settings. Further, Phase III clinical trials (at least in psychiatry) often do not enroll a large enough sample to evaluate infrequently occurring adverse events. Rather, the predominance of information regarding rare side effects is derived from voluntary reports made after a drug comes to market—and therefore likely under-reports the phenomenon. Finally, information regarding drug safety that comes to practitioners in the form of medication warnings or advisories may reflect concerns that extend beyond the strict interpretation of clinical trials data. These and other issues represent major obstacles in attempting to fully understand issues related to safety and tolerability of medication in “real world” settings.

Adult attention-deficit/hyperactivity disorder (ADHD) and the spectrum of depressive disorders have high overlapping prevalence rates. Rates of depression in adults with ADHD and rates of ADHD in depressed adults provide an important epidemiologic background for clinicians treating either or both of these populations. There is a distinctive phenomenology of ADHD and depression, and distinctive diagnostic issues that present with the coexistence of these two disorders.

Creativity in the context of neurologic illness is extremely complicated, but fascinating and inspiring to those who study it. Artistic people with degenerative diseases often are still compelled to engage in their creative talents after developing a neurologic illness. In some cases, people with these disorders even develop new abilities that did not exist prior to onset of illness. Those who study creativity and dementia must first address a fundamental neurologic question: Where in this elegant structure does the ability to produce art come from?

As a result of clinical, epidemiological, neuroimaging, and therapy studies that took place in the late 1980s, obsessive-compulsive disorder (OCD) has been well-characterized in the field of anxiety disorders. Other disorders attracted attention for their similarities to OCD, and were located in the orbit of the disorder. OCD has become known as the “primary domain” of a scientific “metaphor” comprising the putative cluster of OCD-related disorders (OCRDs). It is a “paradigm” with which to explore basal ganglia dysfunction. The OCRDs share common phenomenology, comorbidities, lifetime course, demographics, possible genetics, and frontostriatal dysfunction (particularly caudate hyperactivity.) The adoption of this metaphor analogy has proven useful. However, 15 years since its emergence, the spectrum of obsessive-compulsive disorders remains controversial. Questions under debate include whether OCD is a unitary or split condition, whether it is an anxiety disorder, and whether there exists only one spectrum or several possible spectrums. Further work is needed to clarify obsessive-compulsive symptoms, subtypes, and endophenotypes. There is need to integrate existing databases, better define associated symptom domains, and create a more comprehensive endophenotyping protocol for OCRDs. There is also a need to integrate biological and psychological perspectives, concepts, and data to drive this evolution. By increasing research in this field, the OCD spectrum may evolve from a fragmented level of conceptualization as a “metaphor” to one that is more comprehensive and structured.

Treatment of attention-deficit/hyperactivity disorder (ADHD) may positively impact the neurobiology of adult patients with ADHD. Treatment may also minimize impairment from core symptoms and may alter the course of co-morbid disorders such as depression and substance use disorder. However, much of the information on stimulant use in adult ADHD comes from studies conducted in children, and it remains unclear whether there is a difference between children and adults when it comes to the side effects and tolerability of ADHD treatments. It is known that clinical presentation differs between adults and children, with adults demonstrating a higher percentage of mood disorders. Current treatments for adult ADHD include psychosocial therapies and pharmacologic therapies, the latter of which include the stimulants d-methylphenidate extended release (XR), OROS methylphenidate, lisdexamfetamine, and mixed amphetamine salts XR; and the nonstimulant atomoxetine, a selective norepinephrine reuptake inhibitor. There is need for additional study of treatment strategies for adult ADHD. Although all classes of ADHD medications are approved in adults, there are fewer approved formulations for adults than for children. Efficacy in adults is more subjective than in children, which may affect how efficacy rates for adult treatments are calculated. Adults also present a greater diversion risk than children. In addition, there are several new and emerging medication treatments worth considering.

This Expert Roundtable Supplement represents part 2 of a 3-part supplement series on adult ADHD led by Lenard A. Adler, MD. In this activity, Thomas J. Spencer, MD, discusses the neurobiology and genetics of adult ADHD; Mark A. Stein, PhD, discusses stimulant therapy; and Jeffrey H. Newcorn, MD, reviews nonstimulants and psychosocial treatments.

Alzheimer's disease (AD) is a progressive disorder in which neurodegeneration begins decades before clinical symptoms appear. Detecting AD during this preclinical phase presents both the enormous challenge of identifying at-risk patients prior to symptom onset and the potential reward of treating patients early enough to prevent or slow disease progression. Given that a 5-year delay in the onset of the clinical manifestations of AD could result in almost a 50% reduction in disease prevalence, early detection of AD is a major focus of clinical research. Several objective, measurable indicators of preclinical and clinical characteristics of AD are currently available or in development. These biomarkers are promising because they promote identification of individuals at risk for AD onset and disease progression; diagnostic accuracy and treatment during the early stages of AD; and the development of disease-modifying therapies that may potentially slow or prevent disease progression during the preclinical phase of AD.