Evaluation of psychological treatment in primary care.

As clinical psychology services to primary care have grown considerably in recent years, several papers have examined the impact of such services. Benefits to patients following contact with the psychologist have been described, but the few studies which have used control groups have -not shown long-lasting effects. However, assessing the global effects of psychological treatment creates several methodological problems, and many of the studies have serious shortcomings in their use of sampling procedures and dependent measures. Clear results are unlikely to emerge from such studies because psychological treatment is not a single entity but encompasses a number of interventions for different types of problem. A more differentiated approach to evaluation is needed to assess the effectiveness of psychological treatment services in primary care.