Table 1.
List of the National Institute of Mental Health Diagnostic Interview Schedule (DIS) items used for ascertainment of psychotic symptoms and prevalence estimates in 15 049 participants
| Any positive responsea |
Primary psychotic symptoms (psychotic experiences) |
|||
|---|---|---|---|---|
| DIS items | n | Weighted % (95% CI) | n | Weighted % (95% CI) |
| Have you ever believed people were watching you or spying on you? | 1772 | 13.2 (12.5–14.0) | 195 | 1.3 (1.1–1.6) |
| Was there ever a time when you believed people were following you? | 894 | 6.5 (6.0–7.1) | 97 | 0.6 (0.5–0.8) |
| Have you ever believed that someone was plotting against you or trying to hurt you or poison you? |
606 | 4.1 (3.7–4.5) | 127 | 0.8 (0.7–1.0) |
| Have you ever believed that someone was reading your mind? | 230 | 1.8 (1.5–2.1) | 78 | 0.6 (0.5–0.8) |
| Have you ever believed you could actually hear what another person was thinking, even though he was not speaking or believed that others could hear your thoughts? |
541 | 4.0 (3.6–4.5) | 129 | 0.9 (0.70–1.1) |
| Have you ever believed that others were controlling how you moved or what you thought against your will? |
192 | 1.3 (1.1–1.5) | 88 | 0.6 (0.5–0.7) |
| Have you ever felt that someone or something could put strange thoughts directly into your mind or could take or steal your thoughts out of your mind? |
205 | 1.4 (1.2–1.6) | 72 | 0.4 (0.3–0.6) |
| Have you ever believed that you were being sent special messages through television or the radio? |
143 | 1.0 (0.8–1.3) | 54 | 0.4 (0.3–0.5) |
| Other volunteered delusions | 45 | 0.3 (0.2–0.5) | 25 | 0.2 (0.1–0.3) |
| Have you ever had the experience of seeing something or someone that others who were present could not see – that is, had a vision when you were completely awake? |
964 | 6.2 (5.7–6.7) | 329 | 2.0 (1.8–2.3) |
| Have you more than once had the experience of hearing things other people couldn't hear, such as a voice? |
668 | 4.7 (4.3–5.2) | 305 | 2.0 (1.8–2.4) |
| Any symptom | 3474 | 24.7 (23.8–25.7) | 855 | 5.5 (5.1–6.0) |
a.
Includes the following categories: non-significant symptoms, associated with alcohol or substance use, associated with medical conditions, having plausible explanation and primary psychotic symptoms.