There is no consensus on what the root causes of major depression are; there are probably many causes. Dopamine can definitely affect happiness, but giving a chronically depressed patient L-DOPA once per day generally won&#x27;t treat their depression for very long.<p>On that same note, people with ADHD are often missing dopamine in many parts of the brain, but ADHD isn&#x27;t necessarily correlated strongly with depression. And quick dopamine-releasing drugs like amphetamine (Adderall&#x2F;Dexedrine&#x2F;Vyvanse), or dopamine reuptake inhibitors like methylphenidate (Ritalin&#x2F;Concerta), tend not to be great treatments for depression, either. They can be a short term treatment by giving you a euphoric high the first few times you take them, or if you take big doses, but that&#x27;s not a good long term treatment strategy.