Some individuals with dementia show disinhibited behavior, including making inappropriate jokes, neglecting personal hygiene, exhibiting undue familiarity with strangers, or disregarding conventional rules of social conduct. Occasionally, they may harm others by striking out. Suicidal behavior may occur, especially in mildly impaired individuals, who are more likely to have insight into their deficits and to be capable of formulating (and carrying out) a plan of action. Anxiety is fairly common, and some patients manifest "catastrophic reactions," overwhelming emotional responses to relatively minor stressors, such as changes in routine or environment. Depressed mood, with or without neurovegetative changes, is quite common, as are sleep disturbances independent of depression. Delusions can occur, especially those involving themes of persecution (e.g., the belief that misplaced possessions have been stolen). Misidentifications of familiar people as unfamiliar (or vice versa) frequently occur. Hallucinations can occur in all sensory modalities, but visual hallucinations are most common. Some patients exhibit a peak period of agitation (or other behavioral disturbances) during the evening hours, which is sometimes referred to as "sundowning."