11. Comparison 4: levetiracetam versus placebo: hostility (skewed data).

Study	Outcome	n(Exp)	Mean(Exp)	SD(Exp)	n(Cntrl)	Mean(Cntrl)	SD(Cntrl)	Statistic	Notes
Mattes 2008 mean 1738 mg/day	Change in BPRS hostility subscale, at 10 wks	19	‐1.00	0.94	20	‐0.85	0.95	t = ‐0.14 (ANCOVA; P = 0.89) (see note 1)	Favours neither condition

1. Covariance analysis comparing levetiracetam versus placebo on change scores (final ‐ initial), covarying out the relationship between initial scores and change scores; negative change = good.

BPRS = British Psychiatric Rating scale; wks = weeks