. 2023 Aug 2;80(9):914–923. doi: 10.1001/jamapsychiatry.2023.2345

Table 2. Univariable Analysis of the Association Between FST Items and THC Exposure.

SFST clue	Participants with clues^a		Unadjusted analysis		Adjusted analysis^b
SFST clue	Placebo (n = 63)	THC (n = 121)	OR (95% CI)	P value	95% CI	P value
Walk and Turn Test
Instructions	13 (20.6)	36 (30.0)^c	1.65 (0.80-3.40)	.18	0.76-3.58	.25
Balance	17 (27.0)	56 (46.3)	2.33 (1.20-4.52)	.01	1.04-5.23	.04
Starts too soon	3 (4.8)^d	10 (8.3)	1.77 (0.47-6.69)	.40	0.45-6.92	.45
Stops when walking	20 (32.3)^d	58 (47.9)	1.93 (1.02-3.67)	.04	0.92-4.08	.10
Steps off line	8 (12.9)^d	38 (31.4)	3.09 (1.34-7.13)	.008	1.05-9.11	.04
Wrong number of steps	8 (12.9)^d	29 (24.0)	2.13 (0.91-4.99)	.08	0.82-5.54	.15
Misses heel to toe	9 (14.5)^d	43 (35.5)	3.25 (1.46-7.22)	.004	1.05-10.1	.03
Raises arm to balance	28 (45.2)^d	67 (55.4)	1.51 (0.81-2.79)	.19	0.79-2.88	.25
Improper turn	29 (46.8)^d	60 (49.6)	1.12 (0.61-2.07)	.72	0.61-2.07	.72
Total clues, median (IQR)	2.0 (1.0-3.0)	3.0 (2.0-4.0)	1.52 (1.22-1.88)	<.001	1.17-1.98	<.001
≥2 WAT clues	35 (56.5)^d	92 (76.0)	2.45 (1.27-4.70)	.007	NA	NA
One Leg Stand Test
Puts foot down	10 (16.1)^d	43 (35.8)^c	2.90 (1.34-6.29)	.007	1.20-7.03	.01
Uses arms to balance	21 (33.9)^d	57 (47.5)^c	1.77 (0.93-3.34)	.08	0.90-3.47	.11
Sways	35 (55.6)	102 (84.3)	4.29 (2.14-8.63)	<.001	1.77-10.5	<.001
Hops	2 (3.2)^d	10 (8.5)^e	2.78 (0.59-13.1)	.20	0.59-13.1	.20
Total clues, median (IQR)	1.0 (0.0-2.0)	2.0 (1.0-2.75)	1.84 (1.34-2.54)	<.001	1.26-2.69	<.001
≥2 OLS clues	23 (37.1)^d	69 (58.5)^e	2.39 (1.27-4.49)	.007	NA	NA
≥2 WAT clues and ≥2 OLS clues	17 (27.9)^d^,^f	56 (47.5)^e	2.34 (1.20-4.55)	.01	NA	NA
Finger to Nose Test
Instructions	13 (20.6)	39 (32.2)	1.83 (0.89-3.76)	.10	0.79-4.26	.23
Incorrect sequence	9 (14.3)	21 (17.4)	1.26 (0.54-2.94)	.59	0.52-3.03	.69
Uses pad rather than finger	32 (50.8)	74 (61.2)	1.53 (0.83-2.82)	.18	0.77-3.03	.31
Leaves finger on nose	8 (12.7)	15 (12.4)	0.97 (0.39-2.44)	.95	0.39-2.44	.95
Eyelid tremor	45 (71.4)	91 (75.2)	1.21 (0.61-2.41)	.58	0.60-2.47	.69
Body tremor	6 (9.5)	35 (28.9)	3.87 (1.53-9.78)	.004	1.21-12.3	.02
Sways	22 (34.9)	77 (64.2)^c	3.34 (1.76-6.32)	<.001	1.39-8.02	.002
Total clues, median (IQR)	2.0 (1.0-3.0)	3.0 (2.0-4.0)	1.54 (1.21-1.95)	.001	1.18-2.00	.001
Lack of Convergence
Instructions	3 (4.8)	10 (8.3)	1.80 (0.48-6.80)	.38	0.48-6.80	.38
Eyes do not converge	31 (49.2)	83 (68.6)	2.25 (1.21-4.21)	.01	1.10-4.61	.02
Pupillary diameter, median (IQR), mm^g	5.0 (4.0-6.0)	5.5 (4.5-6.0)	1.31 (0.99-1.74)	.06	NA	NA
Total clues, median (IQR)	1.0 (0.0-1.0)	1.0 (0.0-1.0)	2.31 (1.27-4.20)	.006	1.24-4.32	.007
Modified Romberg Balance Test
Instructions	20 (31.7)	35 (29.2)^c	0.89 (0.46-1.71)	.72	0.44-1.79	>.99
Internal clock, median (IQR), s^h	34 (30-42)	32 (29-36)	0.96 (0.94-0.99)	.004	NA	NA
Internal clock not acceptable	34 (54.0)	49 (40.8)^c	0.59 (0.32-1.09)	.09	0.26-1.32	.45
Eyelid tremors	50 (79.4)	96 (79.3)	1.00 (0.47-2.12)	>.99	0.47-2.12	>.99
Body tremors	17 (27.0)	32 (26.4)	0.97 (0.49-1.93)	.94	0.48-1.95	>.99
Sways	40 (63.5)	87 (73.1)ⁱ	1.56 (0.81-3.01)	.18	0.72-3.40	.45
Total clues, median, (IQR)	2.0 (2.0-3.0)	2.0 (2.0-3.0)	0.93 (0.70-1.24)	.63	0.70-1.24	.63
Total clues for all tests, median (IQR)	8.0 (5.0-11.0)	11.0 (9.0-13.0)	1.23 (1.12-1.35)	<.001	1.12-1.35	<.001

Abbreviations: FST, field sobriety test; NA, not applicable; OLS, One Leg Stand; OR, odds ratio; SFST, standardized field sobriety test; THC, Δ⁹-tetrahydrocannabinol; WAT, Walk and Turn.

^{^a}

Data are presented as the number (percentage) of participants who showed each clue unless otherwise indicated.

^{^b}

Adjusted 95% CIs and P values are based on the false discovery rate method.

^{^c}

n = 120.

^{^d}

n = 62.

^{^e}

n = 118.

^{^f}

n = 61.

^{^g}

Numeric variable (not included in the calculation of total clues).

^{^h}

Numeric variable for the participant’s estimate of when 30 seconds had passed (not included in the calculation of total clues).

^ⁱ

n = 119.