Of these, 11 officers were available for testing 4 years after recruitment. Results support the contention that police service is associated with adverse psychological changes among officers. Changes in MMPI scores over time suggested increasing somatic symptoms, anxiety, and alcohol vulnerability. Initial changes at the end of 2 service years suggest that even early in service, officers may have been responding negatively to the demands of the police social system by expressing addictive behavioral vulnerabilities. The increased vulnerability to alcohol abuse was the strongest finding, and by the fourth year of service, mean MacAndrews Alcoholism Scale scores were within the critical range. This suggests that alcohol abuse may be a preferred coping mechanism for dealing with occupational stressors. Results also suggest a need for periodic reevaluations to prevent stress-related problems and early intervention programs, including intradepartmental programs on stress management, psychological intervention, and education on the abuses and effects of alcohol. 3 tables and 17 references. (Author abstract modified)