IN APPLYING PRINCIPLES OF HUMAN BEHAVIOR TO POLICE WORK, THERE ARE THREE MAJOR DIFFICULTIES: (1) INTERDISCIPLINARY FIELDS OF KNOWLEDGE CONCERNED WITH BEHAVIOR, SUCH AS BIOLOGY, PSYCHOLOGY, AND SOCIOLOGY, OFFER LITTLE PRACTICAL GUIDANCE TO POLICE OFFICERS; (2) BEHAVIORAL PRINCIPLES VALID IN THEORETICAL-CLINICAL SETTINGS ARE NOT ALWAYS APPLICABLE IN REAL WORLD SITUATIONS; AND (3) POLICE OFFICERS CANNOT BE EXPECTED TO BE TOTALLY PROFICIENT IN THE AREA OF HUMAN BEHAVIOR. INDICATORS OF MENTAL DISORDERS OR ABNORMAL BEHAVIOR INCLUDE EXTREME BEHAVIOR THAT HAS NO RATIONAL BASIS, THE INAPPROPRIATENESS OF BEHAVIOR IN PARTICULAR CIRCUMSTANCES, AND EXTREME RIGIDITY OR INFLEXIBILITY. MORE SPECIFIC INDICATIONS OF ABNORMAL BEHAVIOR CONCERN LOSS OF MEMORY, ALTERED IDEAS OF REFERENCE (DELUSIONS OF GRANDEUR OR PERSECUTION), HALLUCINATIONS, IMPOSSIBLE PHYSICAL AILMENTS, AND EXTREME FRIGHT OR DEPRESSION. COMMON MENTAL DISORDERS ARE SCHIZOPHRENIA, PARANOID SCHIZOPHRENIA, PARANOIA, AND MANIA-DEPRESSION. BECAUSE OF THE POTENTIAL VIOLENCE IN CONTACTS WITH DISTURBED PERSONS, POLICE OFFICERS SHOULD MOVE SLOWLY SO AS NOT TO EXCITE THE DISTURBED PERSON IN A CRISIS SITUATION AND SHOULD AVOID EMERGENCY LIGHTS, SIRENS, GATHERING CROWDS, AND THREATENING MANNERISMS. THEY SHOULD COMMUNICATE AND NOT THREATEN, AVOID TOPICS THAT INCITE AGITATION, AND BE TRUTHFUL. IN THE EVENT THAT A DISTURBED PERSON PRESENTS A CLEAR AND PRESENT DANGER, POLICE OFFICERS CAN USE THE FULL POWER OF THEIR POSITION. LESS STRAIGHTFORWARD, HOWEVER, IS THE APPROPRIATE COURSE TO FOLLOW IN THE CASE WHERE THE DISTURBED INDIVIDUAL DOES NOT PRESENT AN IMMEDIATE DANGER. WHETHER BASED ON LEGAL AUTHORITY OR SIMPLE PERSUASION, THE LEAST INTRUSIVE AVENUE OF DISPOSITION IS VOLUNTARY REFERRAL. CUSTODIAL ARREST IS NECESSARY WHEN VOLUNTARY REFERRAL IS NOT INDICATED. IN SOME CASES, THE DISTURBED INDIVIDUAL MUST BE INCARCERATED PENDING DISPOSITION. A DISCUSSION GUIDE ACCOMPANIES THE ARTICLE. (DEP)