Is there a relationship between sunspot numbers and psychiatric admissions?

The authors examined the correlation between solar activity (sunspot numbers) and 96050 psychiatric admissions between July 1984 and December 1993, Victoria, Australia. Calculation of the Pearson correlation coefficient gave a value of 0.399 (P value; 0.0001). This value however, may be an artefact of autocorrelations within the two series rather than a relationship between them as the Pearson correlation does not account for the serial nature of the data. To overcome this problem the authors calculated the prewhitened cross-correlation between the series and tested whether they were uncorrelated. The test was significant (P value; 0.006), which gives strong evidence for a relationship between sunspot number and psychiatric admissions.