Well, at a glance it would seem illogical and pure humbug, but.....
When two or three heavenly bodies come in a straght line their magnetic effects would undobtedly increase. The effects of lunar cycle on the ebb and tide of water (the seas) is a scientific fact and "lunatic" is not just a fancy word nor is the cyclic effect on asthma in relation to the moon cycle.
Since Astrology is based on the planeteray position at birth and during the life time of a person, whether true or not Astrologers have their reasons to predict ill or well effects of the unusual planetery position.
Dr Frank