In my life before retirement I developed treatment plans for adolescents and young adults and applied them while running a private treatment/survival school for teens in Montana. Many of those clients continue to use the physical activity learned at the school to substitute for their prior drug use to this day.
Among the numbers of not quite legitimate bike tourists on the Pacific Coast Route in California, I see some of the "riding wounded". Many have learned by accident to use repetitive physical movement to help manage their mental demons be they from early trauma, war time experiences or from various mental dysfunctions large and small. Endorphins generated while biking can partially or sometimes completely substitute for previous self medication with prescription or street drugs used to manage their chemical roller coaster. We legitimate bike tourists only use touring for stress relief which is totally different!
I have also met various permanent bike tourists who fall in the mild end of the autism spectrum. They describe their comfort with the simplicity and repetitiveness of bike touring. A less complex or less demanding life is more manageable. A disability stipend and/or family donation finances their lives. I see some of them periodically as they move with the seasons heading South to San Diego in the Fall or North toward Oregon in the Spring.
Just a reminder that bike touring is motivated by many different things. Hard economic times forces more folks onto bikes. I welcome the variety.