Does cocaine bind competitively or non competitively to DAT? I was just wondering whether cocaine, once reaching a synapse, binds to a DAT (Dopamine transporter) competitively or non competitively, or neither of them?

Cocaine binds competitively to DAT, though not in precisely the same binding site, rather there is overlap, and many of the same amino acids are involved in binding of each.

Amphetamine and benztropines also bind in the same region.

Beuming, T., Kniazeff, J., Bergmann, M. L., Shi, L., Gracia, L., Raniszewska, K., ... & Loland, C. J. (2008). The binding sites for cocaine and dopamine in the dopamine transporter overlap. Nature neuroscience, 11(7), 780-789.