Phenomenology Of Visual Hallucinations Research Articles

P.3.024 - Visual hallucinations and lifetime use of hallucinogen perception persisting disorder associated recreational drugs: results from a large online survey

Introduction Hallucinogen perception persisting disorder (HPPD) can be defined as the re-experience of altered visual perceptions after use of psychedelic drugs [1,2]. Despite estimated high percentages of recreational use of psychedelic drugs, research data on HPPD are scarcely available [1,2]. Considering the recent emergence of studies on psychedelic drugs as a treatment option for various psychiatric disorders, proper assessment of potentially harmful side effects, such as HPPD, is necessary [3]. This study aims to investigate the association between lifetime use of HPPD-associated drugs and the presence and burden of visual hallucinations in a large general population sample. Methods We used data from a large online survey on hallucinations in the general Dutch population, https://zieikspoken.nl, collected between September 26th, 2016 and May 23rd, 2017. All participants (n=10.289) were aged 14 or over. We assessed lifetime use of 11 commonly used recreational drugs in the Netherlands, out of which LSD, psilocybin, 2-CB and MDMA were considered HPPD-associated based on previous reports [1-4]. Visual hallucinations were assessed using the Questionnaire for Psychotic Experiences (QPE). Presence of visual hallucinations was categorized as follows: never experienced, ever experienced, experienced in past month, experienced in past week. Associations between lifetime use of HPPD-associated drugs and presence and phenomenology of visual hallucinations were calculated using Pearson’s chi-square tests in SPSS. Results A total of 2.175 subjects (21.1% of all participants) indicated having used HPPD-associated drugs at least once in their lifetime. In subjects who had never experienced visual hallucinations, the percentage of lifetime HPPD-associated drug use (18.8%) was significantly lower than in the groups who had experienced visual hallucinations in their lifetime but not recently (23.0%), in the past month (25.2%) or the past week (24.9%). Nevertheless, lifetime use of HPPD-associated drugs did not differ between the groups of subjects with visual hallucinations (ever/past month/past week). Within the group of subjects with visual hallucinations in the past week or month, lifetime HPPD-associated drug users did not differ from non-users in terms of experiencing a significant burden from their visual hallucinations (25.2% vs. 24.1%, respectively; OR 0.9 (95%-CI 0.7-1.2)) or having visual hallucinations with a significant impact on their daily functioning (25.1% vs 23.0%; OR 0.9 (95%CI 0.6 -1.4)). Discussion Our results indicate that lifetime exposure to HPPD-associated drugs is associated with a slight but significant increase in presence of visual hallucinations. However, the experienced burden of current visual hallucinations and their impact on daily functioning does not differ between the exposed and unexposed group. Our study is limited to cross-sectional data not specifically focused on HPPD-like perceptual disturbances. Despite this, our results are in line with previous studies, in which the presence of chronic, burdensome perceptual disturbances after psychedelic drug use is considered a rare phenomenon, whose occurrence relies on an overall vulnerability based on the combined presence of several risk factors, rather than on the lifetime exposure to HPPD-associated drugs alone [1-4]. With regard to future studies on psychedelic drugs, we still recommend to be careful by thoroughly measuring HPPD-like symptoms over time, and studying potentially contributive factors.

Gender difference in the association and presentation of visual hallucinations in dementia with Lewy bodies: a cross-sectional study.

Visual hallucinations (VHs) are among the most striking features of dementia with Lewy bodies (DLB). We investigated gender differences in the association and presentation of VHs in DLB. A cross-sectional analysis of baseline data from a prospective, longitudinal study on dementia was performed. Cumulative frequency, 1-month frequency, and phenomenology of VHs were summarized and compared between female and male patients with DLB. Gender differences in the factors associated with VHs were investigated in patients with and without hallucinations. A total of 152 patients including 65 (42.8%) women and 87 (57.2%) men were analyzed. The cumulative and 1-month frequencies of VHs were 60% and 55.4%, respectively, in women and 44.8% and 41.4%, respectively, in men. Adjusting for age and disease severity resulted in the inclusion of more women in the VH group [odds ratio (OR)=2.33, p=0.028)] than in the non-VH group. In female participants, older age (OR=9.16, p=0.003) and higher neuropsychiatric inventory score (OR=4.89, p=0.009) were associated with VHs, whereas in male participants, more severe dementia stage (clinical dementia rating 2-3 versus clinical dementia rating 0.5, OR=6.22, p=0.008) and higher rates of using antipsychotics (OR=9.64, p=0.047) were associated with VHs. The frequencies of 1-month and cumulative VHs were high in DLB, which indicated a high prevalence as well as a high persistency of VHs in DLB. The patterns of factors associated with VHs differed between female and male patients. Copyright © 2017 John Wiley & Sons, Ltd.

Visual Hallucinations in Eye Disease and Lewy Body Disease

Visual hallucinations (VH) most commonly occur in eye disease (ED), Parkinson disease (PD), and Lewy body dementia (LBD). The phenomenology of VH is likely to carry important information about the brain areas within the visual system generating them. Data from five controlled cross-sectional VH studies (164 controls, 135 ED, 156 PD, 79 [PDD 48 + DLB 31] LBD) were combined and analyzed. The prevalence, phenomenology, frequency, duration, and contents of VH were compared across diseases and sex. Simple VH were most common in ED patients (ED 65% versus LBD 22% versus PD 9%, χ(2) = 31.43, df = 2, p < 0.001), whereas complex VH were more common in LBD (LBD 76% versus ED 38%, versus PD 28%, χ(2) = 96.80, df = 2, p < 0.001). The phenomenology of complex VH was different across diseases and sex. ED patients reported more "flowers" (ED 21% versus LBD 6% versus PD 0%, χ(2) = 10.04, df = 2, p = 0.005) and "body parts" (ED 40% versus LBD 17% versus PD 13%, χ(2) = 11.14, df = 2, p = 0.004); in contrast, LBD patients reported "people" (LBD 85% versus ED 67% versus PD 63%, χ(2) = 6.20, df = 2, p = 0.045) and "animals/insects" (LBD 50% versus PD 42% versus ED 21%, χ(2) = 9.76, df = 2, p = 0.008). Men reported more "machines" (13% versus 2%, χ(2) = 6.94, df = 1, p = 0.008), whereas women reported more "family members/children" (48% versus 29%, χ(2) = 5.10, df = 1, p = 0.024). The phenomenology of VH is likely related to disease-specific dysfunctions within the visual system and to past, personal experiences.

Phenomenology of Visual Hallucinations and Their Relationship to Cognitive Profile in Parkinson’s Disease Patients

Although the phenomenology of visual hallucinations (VHs) has been investigated, no study to date has related cognitive performance to the content of hallucinations, specifically whether participants who have familiar internally driven hallucinations differ in the executive function from patients with externally driven hallucinations. Here, we examine the relationship between executive function and the content of VHs in Parkinson’s disease (PD) patients. We evaluated three groups: 17 PD patients with internally driven memory-based VHs, 18 PD patients with externally driven non-memory-based VHs, and 20 PD patients without hallucinations on a series of tests previously reported to evaluate executive functions, specifically tests of inhibitory ability, short-term memory, and working memory. Differences were found on test of inhibitory ability with PD patients experiencing externally driven VHs having substantially greater impairment than patients with internally driven VHs. These findings indicate that the cognitive profile of patients may influence the content of the hallucinatory experience and could consequently have implications for treatment of the phenomenon.

Clinical characteristics of disclosed visual hallucinations in users of an Early Intervention in Psychosis Service

Visual hallucinations (VH) are ill-understood phenomena, and can be distressing and disabling to people with psychosis. Current models of VH emphasise that the appraisal of the VH helps explain the distress associated with the experiences. However, we were also interested in the content of what people saw in order to determine if distressing content and perceived control may help us understand the distress reported. We report the prevalence and phenomenology of VH in a large number (176) of people experiencing their first episode of psychosis. Care coordinators working with service users in an early intervention in psychosis service were asked about the experiences reported, using a semi structured interview. The findings indicate that around one third of service users at some point report visual hallucinations but only around 11% continue to report distressing visual hallucinations. Most report seeing a human-like figure, some with a particularly unpleasant content and many report having little perceived control over the experiences. For some, then, understanding and addressing the content of the experience, and perceived control, may be important if we are to help people better manage these upsetting experiences.

Dreaming and hallucinations – Continuity or discontinuity? Perspectives from dementia with Lewy bodies

Comparing the phenomenology, neurochemical pathology, and psychopharmacology of hallucinations and dreaming is limited by the available data. Evidence to date reveals no simple correspondence between the two states. Differences in the phenomenology of visual hallucinations and the visual component of dreams may reflect variations in visual context acting on the same underlying mechanism - the minimal visual input during dreaming contrasts with the more substantial perceived context in hallucinations. Variations in cholinergic, dopaminergic and serotonergic neurotransmitter function during sleep and during hallucinations in Lewy body dementias, together with relevant drug effects suggest that, on the whole, different, potentially opposite, changes characterise the two states. A similar analysis of other psychotic features in Lewy body dementia and other disorders suggests that, in contrast to hallucinations, there may be more convincing parallels between dreaming and delusional states.