What happens to human dopaminergic reward system once a teenager becomes adult?

Question

I've recently heard a podcast which explained teenage impulsivity and novelty seeking in part by

• "Lowering the baseline dopamine activity in the reward system"
• "Increase in dopaminergic reward in response to novelty"

I assume that by reward system the author means mesolimbic and mesocortical dompaminergic pathways in the brain.

Here's an article that seems to state similar findings:

Starting in early adolescence and peaking midway through, this enhanced dopamine release causes adolescents to gravitate toward thrilling experiences and exhilarating sensations. Research even suggests that the baseline level of dopamine is lower—but its release in response to experience is higher—which can explain why teens may report a feeling of being “bored” unless they are engaging in some stimulating and novel activities.

The dopamine system here is being compared to the child's dopamine system. I'm interested in what happens to the dopaminergic system once a teenager/adolescent becomes an adult at around the age of 24-25?

I'm looking for insight along these lines - does the reward system of an adult "settle down" and no longer respond to novelty as strongly? Is the baseline dopamine level higher?

Answer 1

This may shed light on why the teenagers response to dopamine changes. Quote from reuniting website

There's much still to learn, but it looks like a number of reward circuitry events occur after climax that have the potential to desensitize us for a time. First, androgen receptors decline after ejaculation, and take up to seven days to normalize. (That means the effects of testosterone on the reward circuitry are probably blunted for a while, quite possibly affecting outlook.) In addition, opioids released during copulation hang around for a while, apparently causing lingering declines in oxytocin, which hamper sexual responsiveness. As noted above, there is also likely a drop in responsiveness to a neurochemical vital to our sense of well-being: dopamine. In effect, the brain has changed. It now requires more stimulation to get the same pleasure response as before, and sometimes no amount of stimulation will truly satisfy—until it recovers. Anecdotal evidence suggests that such changes affect both sexes.

The author further suggests that orgasm and ejaculation increase prolactin levels for up to 14 days, during which the brain is less responsive to pleasure and requires novel entertainment or partners to produce pleasure.

From the info on that site, it seems that the 14 day dopamine-affecting cycle following orgasm continues for as long as a person is sexually active (with orgasms). With this in mind, it appears that the adult response to dopamine release is the same as teenagers who are sexually active.