Any formal, structured psychological or social intervention with assessment, clearly defined treatment plans and treatment goals, and regular reviews (NTA, 2006), as opposed to advice and information, drop-in support or informal keyworking (Pubmed Health glossary)

Psychosocial interventions include structured counselling, motivational enhancement, case management, care-coordination, psychotherapy and relapse prevention.

Resources:

NICE Drug misuse pathway - psychosocial interventions

Key psychosocial intervention publications in the NDC collection