THE CERTIFICATED GLIDER PILOT, THE SOLE OCCUPANT, DEPARTED FOR A LOCAL AREA FLIGHT WITH LIFT CONDITIONS DESCRIBED AS WEAK TO MODERATE. THE WRECKAGE WAS LOCATED ABOUT 2 HOURS AFTER DEPARTURE IN AN AREA OF RUGGED MOUNTAINOUS TERRAIN. THE LEFT WING OF THE GLIDER STRUCK A ROCKY RIDGE AND CAME TO REST ABOUT 300 FEET BELOW THE RIDGE LINE. OTHER GLIDER PILOTS REPORTED THAT THE ACCIDENT PILOT HAD A PROCLIVITY TO FLY OVER MOUNTAINOUS AREAS AT LOW ALTITUDES. A TOXICOLOGICAL EXAMINATION DISCLOSED THE PRESENCE OF A CARDIAC ANTIARRHYTHMIC DRUG. THE QUANTITY OF DRUG FOUND IS CONSIDERED TO BE AT THERAPEUTIC LEVELS. ACCORDING TO A CAMI PHYSICIAN, THE DRUG, IN VIEW OF THE PILOT'S PREVIOUS MEDICAL HISTORY, DID NOT BY ITSELF, PRESENT A DISQUALIFYING CONDITION THAT WOULD HAVE BEEN EXPECTED TO ADVERSELY AFFECT THE PILOT'S ABILITY TO PILOT A GLIDER.