Drowsiness is common in those with DLB and PDD, and can interfere with thinking and memory, as well as quality of life. There are a variety of potential reasons for this, many treatable. Getting a little sleepy during a boring task or napping after lunch on the weekend is not a sign of a medical problem. However, daytime drowsiness should draw attention in certain circumstances: 1. More than one nap most days, or near-daily naps that span 2 to 3 hours 2. Falling asleep during conversations or eating 3. Frequently falling asleep during reading, watching TV, doing computer work or other vigilant tasks 4. Returning to sleep after breakfast These are signs that could indicate that nighttime sleep was not adequate (nonrestorative) but could have other explanations. Daytime drowsiness has limited causes: 1. Insomnia at bedtime 2. Awakening during the night 3. Insufficient time spent in bed at night 4. Poor quality sleep at night (despite adequate time in bed) 5. Daytime medications inducing drowsiness 6. A primary sleep disorder directly causing drowsiness (which may be DLB or PDD related) We will explore each of these possible causes and how they might be diagnosed and treated. If a person with DLB or PDD is excessively drowsy, at least one of these could be the problem. Inability to get to sleep at bedtime can translate into sleepiness during the daytime. Many people with DLB or PDD who experience insomnia benefit from nighttime carbidopa/levodopa doses. The benefits of carbidopa/levodopa dosing at bedtime for Lewy-related insomnia were addressed in Chapter 9. Various other factors, however, may contribute to insomnia. Sometimes medications taken in the evening are alerting. Such drugs include duloxetine (Cymbalta) or venlafaxine (Effexor), used for depression and often dosed twice daily. Elimination of all but the morning dose may allow sleep in such cases. Other drugs for depression from the Prozac class (SSRIs; see the list in Chapter 18) may also cause insomnia if taken at bedtime. A simple strategy is to simply switch to morning dosing on a trial basis. The tricyclic antidepressants, such as nortriptyline, amitriptyline, or protriptyline, should not cause insomnia; they may induce sleep. Occasionally, sleepy people are prescribed stimulants with long-acting properties, such as extended-release methylphenidate (Concerta), modafinil (Provigil), or armodafinil (Nuvigil).