Systems and methods for online assisted pre-intervention or “prevention” are described. A prevention system may provide the ability to initiate a prevention campaign in order to create a customized support forum for persons who may be afflicted by a harmful addiction. The prevention system can receive a request to initiate a campaign for a recipient from a host and facilitate the invitation of other participants to the campaign. Knowledge-based questionnaires may be dynamically generated for the host and participants, and a profile built for the recipient based on received responses. Customized messages may be generated by the prevention system using expert knowledge-based rules, and delivered to the recipient. The messages may be unique to the recipient based on the recipient's circumstances and relationship to the host and participants. Support services provided by the prevention system encourage the recipient to agree to accept help and provide action plan recommendations.