Table 2 Participant demographic and clinical characteristics at the index date
|  | FEP patients (n = 3045) | Matched participants (n = 12,180) | p value |
|---|---|---|---|
Type of psychosis, n (%) | |||
 Non-affective | 2036 (66.9) | NA |  |
 Drug-induced | 678 (22.3) | NA |  |
 Affective | 309 (10.2) | NA |  |
 Pregnancy-related | 22 (0.7) | NA |  |
Year of the index date, median (IQR) | 2010 (2007, 2013) | 2010 (2007, 2013) | Matched |
Age, median (IQR) | 30 (23, 39) | 30 (23, 39) | Matched |
Male, n (%) | 1914 (62.9) | 7656 (62.9) | Matched |
Geographical region, n (%) | Â | Â | Matched |
 London | 271 (8.9) | 1084 (8.9) |  |
 South England | 798 (26.2) | 3192 (26.2) |  |
 Midlands and East England | 599 (19.7) | 2396 (19.7) |  |
 North England | 532 (17.5) | 2128 (17.5) |  |
 Northern Ireland | 168 (5.5) | 672 (5.5) |  |
 Scotland | 356 (11.7) | 1424 (11.7) |  |
 Wales | 321 (10.5) | 1284 (10.5) |  |
Smoking, n (%) |  |  | < 0.0001 |
 Non-smoker | 1011 (33.2) | 6041 (49.6) |  |
 Ever smoker | 1764 (57.9) | 4031 (33.1) |  |
 Unknown | 270 (8.9) | 2108 (17.3) |  |
Alcohol consumption, n (%) | Â | Â | NS |
 Non-drinker | 298 (9.8) | 1026 (8.4) |  |
 Ever drinker | 1742 (57.2) | 5907 (48.5) |  |
 Unknown | 1005 (33.0) | 5247 (43.1) |  |
Body mass index, median (IQR) | 23.8 (21.0, 27.9) | 24.5 (21.6, 28.3) | < 0.0001 |
 < 18.5 kg/m2 (underweight), n (%) | 150 (4.9) | 326 (2.7) |  |
 ≥  18.5 kg/m2 and < 25 kg/m2 (normal), n (%) | 1085 (35.6) | 3578 (29.4) |  |
 ≥ 25 kg/m2 and < 30 kg/m2 (overweight), n (%) | 501 (16.5) | 2025 (16.6) |  |
 ≥ 30 kg/m2 (obese), n (%) | 355 (11.7) | 1355 (11.1) |  |
 Unknown, n (%) | 954 (31.3) | 4896 (40.2) |  |
Number of different prescriptions in 5 years before the index date, median (IQR) | 4 (3, 6) | 3 (1, 5) | < 0.0001 |
Number of GP consultations in 5 years before the index date, median (IQR) | 55 (29, 95) | 25 (10, 53) | < 0.0001 |
 4–5 years prior to the index date | 6 (2, 15)†| 3 (1, 9) | < 0.0001 |
 3–4 years prior to the index date | 7 (2, 16)†| 4 (1, 10) | < 0.0001 |
 2–3 years prior to the index date | 8 (2, 18)†| 4 (1, 11) | < 0.0001 |
 1–2 years prior to the index date | 9 (3, 20)†| 4 (1, 11) | < 0.0001 |
 0–1 year prior to the index date | 17 (8, 30)†| 4 (1, 12) | < 0.0001 |
Number of symptom records in 5 years before the index date, median (IQR)‡ | 2 (1, 5) | 0 (0, 1) | < 0.0001 |