Skip to main content

Table 2 Results before, after four weeks of L-lysine treatment, and after four weeks of placebo treatment.

From: L-lysine as adjunctive treatment in patients with schizophrenia: a single-blinded, randomized, cross-over pilot study

Outcome measure Baseline Post L-lysine Post placebo F value P-value*
L-lysine blood conc (μmol/l) 196 ± 14 (201 ± 15) 401 ± 74 (363 ± 64) 195 ± 13 (195 ± 10) 7.84 (6.57) 0.024 (0.027)
Symptom severity scales      
PANSS      
Positive symptoms 14.6 ± 0.7 (16.0 ± 1.1) 11.9 ± 0.6 (13.5 ± 1.3) 11.6 ± 0.8 (13.4 ± 1.4) 13.11 (12.49) 0.001 (0.000)
Negative symptoms 18.4 ± 2.4 (19.7 ± 2.2) 17.4 ± 2.2 (19.4 ± 2.2) 17.3 ± 2.4 (18.8 ± 2.2) 1.53 (0.69) 0.25 (0.51)
General symptoms 31.3 ± 2.5 (33.5 ± 2.5) 29.5 ± 1.9 (32.3 ± 2.4) 29.1 ± 2.0 (30.9 ± 2.0) 2.14 (2.84) 0.16 (0.09)
Total 64.3 ± 4.2 (69.2 ± 4.7) 58.8 ± 4.0 (65.2 ± 5.4) 58.0 ± 4.5 (63.1 ± 5.0) 13.36 (8.59) 0.001 (0.002)
GAF 43.8 ± 1.8 (42.0 ± 1.9) 46.9 ± 1.6 (45.8 ± 1.6) 44.1 ± 2.3 (42.8 ± 2.1) 4.29 (7.34) 0.035 (0.005)
CGI 3.63 ± 0.18 (3.80 ± 0.20) 3.63 ± 0.18 (3.80 ± 0.20) 3.50 ± 0.27 (3.70 ± 0.26) 1.00 (1.00) 0.39 (0.39)
Depression scale      
MADRS 8.50 ± 2.09 (9.10 ± 1.74) 7.50 ± 1.90 (7.90 ± 1.57) 8.38 ± 1.74 (8.40 ± 1.38) 0.54 (0.89) 0.59 (0.43)
Cognitive tests      
RAVLT 45.9 ± 4.3 (43.5 ± 4.2) 46.0 ± 4.6 (43.3 ± 4.4) 48.8 ± 3.5 (45.2 ± 4.1) 0.79 (0.48) 0.47 (0.62)
CPT 0.76 ± 0.16 (0.67 ± 0.13) 0.81 ± 0.13 (0.76 ± 0.12) 0.86 ± 0.13 (0.71 ± 0.14) 0.25 (0.21) 0.77 (0.81)
Trail Making Test A 33.8 ± 1.7 (39.2 ± 5.9) 31.3 ± 2.5 (39.9 ± 8.9) 35.3 ± 4.5 (40.8 ± 6.3) 0.44 (0.07) 0.58 (0.93)
Trail Making Test B 77.4 ± 7.2 (134 ± 56) 70.0 ± 5.2 (119 ± 48) 71.3 ± 6.4 (124 ± 50) 0.40 (1.61) 0.68 (0.24)
Letter and number span 8.13 ± 0.90 (7.00 ± 1.03) 9.00 ± 0.66 (8.10 ± 0.82) 9.13 ± 0.92 (8.50 ± 0.95) 0.74 (1.92) 0.50 (0.18)
Wisconsin Card Sorting      
Number of errors 33.9 ± 10.0 (31.9 ± 9.0) 21.0 ± 7.2 (19.7 ± 6.5) 24.4 ± 10.1 (23.2 ± 9.0) 4.91 (5.45) 0.024 (0.016)
Perseverant errors 20.4 ± 7.6 (19.0 ± 6.8) 11.5 ± 5.0 (10.7 ± 4.4) 14.8 ± 8.1 (13.4 ± 7.3) 4.46 (5.00) 0.032 (0.021)
Perseverant answers 23.6 ± 9.6 (21.9 ± 8.7) 13.1 ± 6.6 (21.1 ± 5.9) 17.1 ± 10.3 (15.6 ± 9.2) 4.77 (5.20) 0.026 (0.018)
  1. Mean values outside parenthesis refers to analysis including individuals who did display an increase in blood levels of L-lysine during the L-lysine treatment period (n = 8). Mean values within parenthesis refer to statistical analysis performed on all individuals, that is, also those not displaying increased blood levels of L-lysine during the L-lysine treatment period (total n = 10). *Corrected by the Huynh-Feldt procedure as required.