Our project assesses the medications prescribed to people with either pervasive developmental disorders (PDD) or sleep disorders. We wished to compare these rates of prescription to the general population in Southern California living in rural, suburban, and urban areas.

PDD is associated with difficulties both staying and falling asleep likely due to disruptions of circadian rhythms. Artificial light at night, often associated with living in urban areas, is one factor that can impair the proper, timed release of melatonin, leading to an altered sleep/wake cycle. Many prescription medications are designed to alleviate these effects through various mechanisms of action.

We categorized the neighborhoods in Southern California in our study by the amount of light pollution at night using the Bortle Dark-Sky Scale. Using i2b2 Center records, the number of patients in each neighborhood with sleep disorders/PDD was identified, along with those who were prescribed certain medications. We compared the rates of sleep disorders in people with PDD across Bortle scores as well as with the general population. Similarly, we compared the rates of people with PDD on sleep medications across Bortle scores and the general population.

When compared to the general population across Southern California neighborhoods, individuals with PDD have significantly higher rates of sleep disorders. While the rate of sleep disorders in the general population varied depending on the neighborhood’s respective level of light pollution, the percentage of individuals with sleep disorders and PDD remained consistent. Additionally, we found that individuals with PDD did not always receive the same sleep medications as the general population.  

Light pollution may contribute to sleep disorders in people with PDD, however, the involvement of other causal factors is likely, which provides an explanation for why sleep medications demonstrate different efficacy in people with PDD compared to the general population.