As the saying goes, you can have too much of a good thing. And dopamine is no exception. Research shows that besides driving addiction, an overactive dopamine system can cause impulse-control problems, such as compulsive sexual behavior, also known as hypersexuality (via Neuropsychopharmacology).
Dopamine can give your brain and body a kick, but it can also create overstimulation, setting off behavioral issues like aggression and impulsivity. Researchers found that when dopamine is released in high amounts, aggressive behavior heightens, and when the dopamine pathway is blocked, aggression appears to subside (via Nature Communications). High-dopamine individuals tend to be less empathetic and caring, and more masculine and competitive in their behaviors (via Molecular Neurobiology).
An excess of dopamine is also believed to be at the root of schizophrenia (via World Psychiatry). It’s hypothesized that there may be too many dopamine receptors in the brain, triggering some of the positive symptoms associated with the disorder, including hallucinations, delusions, and psychosis. On the other hand, negative symptoms like apathy, social withdrawal, and an inability to feel pleasure may stem from low dopamine. The condition is generally treated and managed with medication that blocks the brain’s dopamine receptors (via Cochrane Database of Systematic Reviews).