Table 3.

Correlation between clozapine dosage (mg day⁻¹ kg⁻¹) and plasma clozapine concentrations (Spearman correlations)

	All samples	Male (n = 116)	Female (n = 77)	<40 years (n = 82)	≥40 years old (n = 111)	Male smokers (n = 50)	Male non-smokers (n = 66)
CLZ (ng ml−1)	r = 0.264**	0.352**	0.120	0.365**	0.124	0.371**	0.268*
NCLZ (ng ml−1)	r = 0.420**	0.485**	0.310**	0.449**	0.358**	0.505**	0.374**
Sum (ng ml−1)	r = 0.322**	0.410**	0.177	0.400**	0.203**	0.418**	0.327**
NCLZ/CLZ	r = 0.151*	0.132	0.267**	0.061	0.214*	0.058	0.148

^**Correlation is significant at the 0.01 level (two-tailed).

^*Correlation is significant at the 0.05 level. CLZ, Clozapine; NCLZ, norclozapine.