Efficacy of Psilocybin in OCD: a Double-Blind, Placebo-Controlled Study.

Assesses severity and types of OCD symptoms over the past seven days. Consists of two parts: 1- symptom checklist, 2- symptom severity scale. The most prominent obsessions and compulsions are identified by the checklist and then rated by the symptom severity scale. The symptom severity scale consists of 11 items (3 items are not included in the total score) and uses a 0 to 4 severity scale. Total Y-BOCS scores range from 0 to 40, with higher scores indicating greater severity of OCD symptoms.

A clinician-administered measure of specific participant OCD symptoms over prior 24 hours. The most prominent obsessions and compulsions that were previously identified by the checklist are rated by the symptom severity scale. The symptom severity scale consists of 11 items (3 items are not included in the total score) and uses a 0 to 4 severity scale. Total A-YBOCS scores range from 0 to 40, with higher scores indicating greater severity of OCD symptoms.

A self-report measure of severity of and distress related to OCD symptoms over the past 24 hours. Consists of 5 items assessing compulsive urges, obsessions, anxiety, mood, and discomfort, each on a 0-100 VAS, with higher scores on each item indicating greater severity.

A clinician-administered measure of suicidality since the last visit. Consists of 5 items assessing suicidal ideation and 6 items assessing suicidal and non-suicidal self-injurious behaviors. Higher scores on either scale indicate more severe suicidal ideation and suicidal or non-suicidal behaviors since the last study visit.

Resting-state brain connectivity will be assessed before and 48 hours after treatment. Neuronal activation induced by OCD-relevant provocative stimuli will be assessed 48 hours after the treatment.

Assesses depression symptoms. Consists of 10 items and uses a 0 to 6 severity scale. Total scores range from 0 to 60, with higher scores indicating more severe depression.

Assesses depression symptoms. Consists of 21 items and uses a 0 to 3 severity scale. Total scores range from 0 to 63, with higher scores indicating more severe depression.

Measures dysfunctional beliefs in obsessive-compulsive disorder. Consists of 44 items that are rated on a seven-point Likert scale, ranging from 1 (disagree very much) to 7 (agree very much). It contains three subscales: overestimations of threat and responsibility for harm (RT subscale), importance and control of intrusive thoughts (ICT subscale), and perfectionism and the need for certainty (PC subscale), with higher scores indicating higher levels of each sub-scale.

An inventory of OCD symptoms. Consist of 18 items that are rated on a 5-point Likert scale. Total scores range from 0 to 72, with higher scores indicating more severe OCD symptoms.

Measures different OCD dimensions. Consists of 20 items assessing two core dimensions of OCD: harm avoidance (10 items) and incompleteness (10 items). Each item is rated from 0: never applies to me to 4: always applies to me. Higher scores on questions assessing harm avoidance indicates greater levels of harm avoidance. Higher scores on questions assessing incompleteness indicates higher levels of incompleteness.

Measures state and trait anxiety. Consist of 40 items: 20 items measuring S-Anxiey and 20 items measuring T-Anxiety. State Anxiety Scale (S-Anxiety) evaluates the current state of anxiety. The Trait Anxiety Scale (T-Anxiety) evaluates relatively stable aspects of anxiety. The S-Anxiety scale assesses the intensity of current feelings "at this moment" from 1(not at all) to 4 (very much so). The T-Anxiety scale assesses the frequency of feelings "in general" from 1 (almost never) to 4 (almost always). The range of scores for each subtest is 20-80, with higher scores indicating greater anxiety.

Assesses quality of life and functionality. Consists of 16 items which are rated from 1 (very poor) to 5 (very good). Total score involves summing only the first 14 items to yield a raw total score. The raw total score ranges from 14 to 70. The raw total score is transformed into a percentage, with higher percentages indicating greater quality of life.

Assesses different experiential aspects of psilocybin. Consists of 44 items which provides scale scores for each of seven domains of mystical experiences: Internal Unity (6 items); External Unity (6 items); Transcendence of Time and Space (8 items); Ineffability and Paradoxicality (5 items); Sense of Sacredness (7 items); Noetic Quality (4 items). Participants are asked to look back on the extended session that they have just experienced and to rate the degree of their experience of the following phenomena. Each item is rated from 0 (none; not at all) to 5 (extreme; more than ever before in my life and stronger than 4). Total scores are expressed as a proportion of the maximum possible score.

Assesses individual meaning in life. Participants are asked to name up to seven domains that they judge to be important to their individual meaning in life.Then they will rate their current level of satisfaction in each of these domains using a seven-point Likert scale (range, -3 to +3) and rate the importance of each of their chosen areas using a eight-point adjectival scale (range, 0 to 7). Higher total score indicate a greater meaning in life.

Assesses difficult experiences induced by the interventions. Consists of 26 items that are rated from 0 (none; not at all) to 5 (extreme; more than ever before in my life). Participants are asked to rate the degree to which at any time during the previous session they experienced the following phenomena. Items are grouped into the following subscales: fear, grief, physical distress, insanity, isolation, death, and paranoia. Scores of each item are transformed into a percentage of the highest possible score. Subscale scores are calculated by averaging the transformed scores of the items in each subscale. The total score is the average of all the transformed item scores, with higher scores indicating more challenging experiences.

Assesses different mental states induced by the interventions. Consists of 94 items which are rated by placing marks on a horizontal visual analogue scale (100 millimeters in length). The scale ranges from no, not more than usual (on the left) to yes, very much more than usual (on the right). The items are scored by measuring the millimeters from the low end of the scale to the participant's mark (from 0 to 100).

Assesses different dimensions of the emotional experience. This scale consists of 60 words and phrases that describe different feelings and emotions. For each item participants rate to what extent they have felt this way during the past few weeks from 1 (very slightly or not at all) to 5 (extremely). The items are grouped into the following 4 subgroups and subscales; general dimension scales (negative affect, positive affect), basic negative emotion scales (fear, hostility, guilt, sadness), basic positive emotion scales (joviality, self-assurance, attentiveness), other affective states (shyness, fatigue, serenity, surprise). The items pertaining to each subscale are summed with higher scores indicating higher levels of each subscale.

Assesses effects of Psilocybin. Consists of 86 items that assess eight categories of possible change in attitudes, mood, social effects, and behavior: 1. positive attitudes about life and/or self (17 items); 2. negative attitudes about life and/or self (17 items); 3. positive mood changes (4 items); 4. negative mood changes (4 items); 5. altruistic/positive social effects (8 items); 6. antisocial/negative social effects (8 items); 7. positive behavior changes (1 item); and 8. negative behavior changes (1item). Each item is rated using a 6-point rating scale from 0 (none, not at all) to 5 (extreme). Higher scores of each subscale indicate greater changes in that category.

Assesses the affective, cognitive, and experiential aspects of individuals' connection to nature. Consists of 21 items which are rated on a 7-point Likert scale. The total score is calculated by averaging all 21 items after the appropriate items are reversed scored. Higher score indicate a greater connection with nature.

Assesses opinions towards the importance of pro-environmental behaviors. Consists of 17 items that are rated from 1(not at all important) to 7 (extremely important). Higher total scores indicate a greater level of importance of pro-environmental behaviors.

Assesses individual differences in anthropomorphism. Consists of 15 items which are rated by a 10-point Likert scale. Higher total scores indicate a higher level of anthropomorphism.

Assesses beliefs of mind-body dualism. Consists of 11 items that are rated on a 7-point Likert scale. The total score is calculated after the appropriate items are reversed scored. Higher scores indicate a greater belief in mind-body dualism.

Measures perceived interpersonal connectedness. A single-item, pictorial measure of closeness. Images range from the self and other as completely separate to the self and other almost completely overlapping.

Assesses moral relativism and idealism. Consists of 20 items that are rated using a 9-point Likert scale (completely disagree to completely agree). Idealism scores are calculated by summing responses from items 1 to 10. Relativism scores are calculated by summing responses from items 11 to 20. Higher scores on items 1 to 10 indicate higher relativism and higher scores on items 11 to 20 higher idealism.

Assesses alcohol consumption, drinking behaviors, and alcohol-related problems. Consists of 10 items. The total score is calculated by summing all items. Higher scores indicate higher alcohol consumption. A score of 8 or more is considered to indicate hazardous or harmful alcohol use.

Assesses frequency of urgent care and emergency room use. Consists of 26 items and 7 scales which include: Hypertension, High Cholesterol, Diabetes, Autoimmune, Musculoskeletal, Emergency Room Utilization, Urgent Care Utilization, Hospital Utilization, Facility Based Mental Health Care Utilization, Non-facility Based Mental Health Care Utilization. Items in each scale are scored by comparing follow-up scores to baseline scores. Positive difference indicates improved condition severity (Hypertension, High Cholesterol, Diabetes, Autoimmune, Musculoskeletal). Positive difference indicates reduced Emergency Room Utilization, Urgent Care Utilization, Hospital Utilization, Facility Based Mental Health Care Utilization, Non-facility Based Mental Health Care Utilization.

Assesses drug-related problems. Consists of 11 items. The total score is calculated by summing all items. Drug related problems are indicated with a score of 6 or more for men and a score of 2 or more for women.

Assesses tobacco use, motivation to quit, and dependence. Consists of 13 items. The baseline score of each item is compared to the follow-up score to assess changes. Higher scores indicate greater nicotine use.

Assesses sleep quality. Consists of 19 self-rated questions and 5 questions rated by the bed partner or roommate (if one is available). Only self-rated questions are included in the scoring. The 19 self-rated items are combined to form seven "component" scores, each of which has a range of 0-3 points. In all cases, a score of "0" indicates no difficulty, while a score of "3" indicates severe difficulty. The seven component scores are then added to yield one "global" score, with a range of 0-21 points, "0" indicating no difficulty and "21" indicating severe difficulties in all areas.

Assesses readiness to change. Consists of 30 items rated from 1(strongly disagree ) to 5 (strongly agree). Subscales include: Precontemplation, Contemplation, Action, and Maintenance. Subscale scores are calculated by averaging the items in each subscale. The total score is calculated by summing the subscales Contemplation, Action, Maintenance and subtracting Precontemplation. Higher score indicate greater readiness to change.

Assesses symptom severity and treatment response. Consists of 4 items that are rated on a 7-point Likert scale. Symptom severity scores range from 1 (normal) through to 7 (amongst the most severely ill patients). Treatment response scores range from 1 (very much improved) through to 7 (very much worse). Each component is rated separately; this measure does not yield a global score. Higher scores indicate greater symptom severity and lower treatment response.

Assesses functional impairment in three inter-related domains; work/school, social and family life. Impairment of each domain is rated from 0 (not at all) to 10 (extremely). The 3 items are summed into a single dimensional measure of global functional impairment that rages from 0 (unimpaired) to 30 (highly impaired).

Assesses individual differences in generalized optimism versus pessimism. Consists of 10 items that are rated from 0 (I agree a lot) to 4 (I disagree a lot). Of the 10 items, 3 items measure optimism, 3 items measure pessimism, and 4 items serve as fillers. Total scores are calculated by summing all items for a total ranging from 0 to 24.There are no "cut-offs" for optimism or pessimism; this measure is used as a continuous dimension of variability.

Assesses OCD symptoms across five dimensions: (1) obsessional thoughts about harm to oneself or others; (2) obsessional impulses to harm oneself or others; (3) contamination obsessions and washing compulsions; (4) checking compulsions; and (5) dressing/grooming compulsions. Consists of 39 items that are rated from 0 (not at all) to 4 (very much). Items within each domain are summed for subscale scores. All items are summed for a total score with higher scores indicating greater symptom severity.

Assesses individual variation in identification of several motor actions and activities. Comprises 25 items of various motor actions or activities, of which each can be endorsed and interpreted on a binary response scale as either a literal motor action or a meaningful outcome-oriented behavior. Greater number of items responded literally or meaningfully indicate more literal or meaningful, outcome-oriented behaviors, respectively.

Assesses reactions to research participation. Consists of 26 items (each rated from 1-5) assessing various aspects of participation-related reactions, which can be parsed into 5 subscales: perceptions of participation, personal benefits, emotional reactions, perceived drawbacks, and global evaluation. Higher subscale scores indicate greater extent of respective reactions.