Dopamine? is a neurotransmitter, which means it controls communication in the brain. Dopamine can tell a neuron to fire off a signal or not, and modulates the signals. Having too much dopamine in the wrong place can make you psychotic. Therefore high amounts of dopamine can cause euphoria, aggression and intense sexual feelings. In the contrary, what could happen without dopamine or with insufficient or inefficient dopamine? It can cause mental retardation, also problems are implicated in ADHD, Alzheimer's, depression, bipolar disorders, binge eating etc.