The present disclosure generally relates to a crystalline form of 6-[(4S)-2-methyl-4-(naphthyl)-1,2,3,4-tetrahydroisoquinolin-7-yl]pyridazin-3-amine. The present disclosure also generally relates to pharmaceutical compositions comprising the crystalline form, as well of methods of using a crystalline form in the treatment of depression and other conditions and methods for obtaining such crystalline form.