What's missing, crucially, is vigorous and prolonged stimulation of meso(cortico-)limbic dopamine function.
This is really much more fun than it sounds. The currently available experimental evidence has persuaded many - but not all - researchers that the mesolimbic dopamine system serves as the final common pathway for pleasure in the brain. Enhanced responsiveness of post-synaptic dopamine D2/D3 receptors is crucial to long-term emotional well-being. The otherwise anomalous mood-brightening effects of the serotonin-reuptake accelerator tianeptine, for instance, are probably explained by its tendency to increase extracellular concentrations of dopamine in the nucleus accumbens. All "serotonergic" and "noradrenergic" mood-brighteners eventually act on the mesolimic dopamine pathway, albeit in differing degrees and with varying delay. And new anti-Parkinsonian and anti-Alzheimer's agents, notably roxindole and pramipexole, owe their exciting potential role as fast-acting antidepressants to their dopaminergic action.
The full story is inevitably complex. Dopamine isn't itself the magic pleasure-chemical, though its functional role is crucial. Researchers into affective disorders readily get over-attached to a particular neurotransmitter, its receptor sub-types and their signal transduction cascades. Traditionally, serotonin and noradrenaline have attracted the fiercest rival partisans. "Dopaminergic" (and opioid) agents, by contrast, are suspect. They are politically incorrect since they are both potentially "abusable". Moreover safe and sustainable empathogens are arguably as morally urgent as safe and sustainable mood-boosters. At any rate, mesolimbic activation, exclusively or otherwise, enhances the intensity of experience; increases pleasure and libido, and boosts cognitive performance. Even better, certain dopamine-enhancing drugs may have neuro-protective properties too.
So what are the other contemporary options for chemical life-enhancement?
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