Abstract: Methods of treating Alzheimer's disease and other neurodegenerative and/or neurocognitive and/or neurodevelopmental diseases are described. The methods comprise the administration of compounds that modulate an activity of cell division control protein 42 (Cdc42), such as the interaction between Cdc42 and intersectin (ITSN). Exemplary modulator compounds include thioureas, disulfonamides of fused aromatic systems (e.g., benzofuran), and acyl hydrazones, among others. Some of the modulator compounds act as activators of Cdc42, while others act as inhibitors. In some cases, the modulator compound has dual functionality and the ability of the modulator compound to act as an inhibitor or activator depends on whether or not Cdc42 is already activated in a particular disease stage or biological environment by an upstream activating signal of Cdc42.