“…Studies by van Praag and others have shown that the turnover of DA in depressive patients may be lowered in particular, when motor inhibition (fcor example, psychomotor inhibition, retardation and apthy) are prominent (Korf & van Praag,197 la, van Praag et al, 1973). L-DOPA, a substance which, in the brain, is converted mainly into DA, has a therapeutic effect in these patients-in particular, where motor pathology is concerned (Goodwin et al, 1970).…”