Table 3.
Demographics, cognition and clinical characteristics of schizophrenia patients with (SCZ(+)) and without (SCZ(−)) cannabis use disorders and healthy subjects
| Patients with schizophrenia |
p | Confidence intervals |
||
|---|---|---|---|---|
| SCZ(−) (n = 13) | SCZ(+) (n = 14) | |||
| Age, in years | 31±9 (18–46)a | 29±9 (18–45) | ns | (−5.14, 9.14) |
| Gender (male/female) | 7/6 | 10/4 | nsb | |
| Years of education | 13±1 (11–15) | 11±1 (9–14) | <0.0005 | (1.21, 2.79) |
| Age at onset of psychosis, in years | 21±5 (12–29) | 20±4 (15–32) | ns | (−2.58, 4.58) |
| Age at onset of cannabis use, in years | 16±1 (14–18) | |||
| Duration of psychotic illness, in years | 10±9 (0–28) | 9±9 (1–27) | ns | (−6.14, 8.14) |
| Symptoms: | ||||
| Brief Psychiatric Rating Scale (BPRS) Total Score | 28±8 (19–47) | 29±7 (19–46) | ns | (−6.95, 4.95) |
| Scale for the Assessment of Negative Symptoms (SANS) Total Score | 5.8±4.7 (0–13) | 8.0±3.9 (2–16) | ns | (−5.61, 1.21) |
| Subscales: | ||||
| Flat affect | 1.8±1.5 (0–4) | 2.0±1.3 (0–4) | ns | (−1.31, 0.91) |
| Alogia | 1.0±1.2 (0–3) | 1.1±1.2 (0–3) | ns | (−1.05, 0.85) |
| Avolition | 1.3±1.4 (0–3) | 2.5±1.3 (0–5) | <0.0317 | (−2.27,−0.13) |
| Anhedonia | 1.7±1.4 (0–4) | 2.3±1.4(0–4) | ns | (−1.71, 0.51) |
| Cognitive testingc: | ||||
| WRAT-3 reading subtest | 85±15 (61–107) | 92±14 (60–111) | ns | (−18.50, 4.50) |
| CPT-IP, fndprime | 0.9±0.7 (−0.3–2.1) | 1±0.8 (0.0–2.6) | ns | (−0.70, 0.50) |
| Digit Span Forward | 6±1 (4–7) | 7±1 (5–9) | <0.0485 | (−1.79, −0.21) |
| Digit Span Backward | 4±1 (2–5) | 4±1 (3–6) | ns | (−0.79, 0.79) |
| CVLT | 33±10 (11–48) | 36±14 (18–60) | ns | (−12.71, 6.72) |
| COWAT, Phonemic Fluency | 32±7 (19–42) | 31±14 (14–62) | ns | (−7.89, 9.89) |
| COWAT, Semantic Fluency | 14±6 (6–23) | 14±5 (8–23) | ns | (−4.37, 4.37) |
| Trail Making A | 49±28 (29–132) | 34±18 (14–87) | ns | (−3.52, 33.52) |
| Trail Making B | 151±72 (61–300) | 110±53 (39–213) | ns | (−8.86, 90.86) |
| Iowa Gambling Task: | ||||
| Total amount of money won/lost ($) | −1157±807 | −1424±921 | ns | (−421.82, 955.82) |
| (−2400–460) | (−3015–500) | |||
| Total number of cards chosen from: | ||||
| Deck A′ | 21±8 (2–36) | 20±6 (10–29) | ns | (−4.58, 6.58) |
| Deck B′ | 33±11 (21–56) | 32±11 (16–51) | ns | (−7.73, 9.73) |
| Deck C′ | 24±7 (13–41) | 22±5 (14–34) | ns | (−2.80, 6.80) |
| Deck D′ | 22±6 (11–33) | 26±8 (14–43) | ns | (−9.64, 1.64) |
| Net scoresd | ||||
| Trials 1–20 | −2.8±5 (−16–4) | −2.4±4 (−10–2) | ns | (−3.98, 3.18) |
| Trials 21–40 | −0.6±7 (−16–14) | 2.4±6 (− 6–14) | ns | (−8.16, 2.16) |
| Trials 41–60 | −1.8±5 (−10–6) | 1.1±9 (−14–18) | ns | (−8.74, 2.94) |
| Trials 61–80 | −0.3±4 (−8–8) | −1.3±7 (−16–10) | ns | (−3.57, 5.57) |
| Trials 81–100 | −2.5±8 (−18–12) | −2.7±8 (−18–8) | ns | (−6.15, 6.55) |
| Total Net score (sum of Net scores) | −8.0±17 (−46–14) | −2.9±18 (−30–22) | ns | (−19.00, 8.81) |
| Categorical scores | ||||
| Trials 1–60 (0/1)e | 9/4 | 5/9 | nsb | |
| Trials 61–100 (0/1) | 7/6 | 8/6 | nsb | |
| Expectancy-Valence Model | ||||
| Recency parameter | 0.16±0.17 (0–0.50) | 0.31±0.41 (0–1) | ns | (−0.40, 0.10) |
| Attention to Wins/Losses parameter | 0.41±0.42 (0–1) | 0.44±0.44 (0–1) | ns | (−0.37, 0.31) |
| Choice consistency parameter | 0.11±3.2 (−5–5) | 0.81±2.79 (−5–5) | ns | (−3.08, 1.68) |
a
Mean ± standard deviation (range).
b
Chi-square or Fisher's Exact (when n < 5 in one of the cells) test.
c
On all tests except Trails A and Trails B, higher scores represent better performance. Trails A and B are time to completion, thus higher scores reflect worse performance.
d
Net score: number of cards chosen from advantageous decks (C′ or D′) minus number of cards chosen from disadvantageous decks (A′ or B′) during 20 trials.
e
Categorical scores = 1 if ∑ net scores for trials 1–60 or trials 61–100 ≥ 0, and =0 if ∑ net scores for trials 1–60 or trials 61–100 < 0.