Introduction: Social isolation is closely associated with negative mental health outcomes. Social media platforms may expand opportunities for social contact, but whether online interactions are as effective as face-to-face, or in-person, interactions at protecting against the negative effects of social isolation is unclear.

Methods: Participants consisted of U.S. military veterans who served since September 2001 and used Facebook (n = 587). Our independent variables were frequency of social contact occurring in-person and on Facebook. Dependent variables were probable psychiatric disorders and suicidality, measured using several validated screening tools. The independent effect of each form of social contact was assessed using multivariate logistic regression, which included adjustment for several potential confounders.

Results: We found that veterans who frequently interacted on Facebook engaged in more in-person social contact than infrequent Facebook users (p < .001). More frequent in-person social interaction was associated with significantly decreased risk of symptoms of major depression and PTSD, compared with contact every few weeks or less. In contrast, increased frequency of social interaction on Facebook had no associations with mental health outcomes.

Limitations: All associations are cross-sectional (direction of association is unclear) and based on self-report measures.

Conclusions: Although veterans who frequently use Facebook are also typically social in their offline life, it is their offline (in-person) social interaction, rather than their social contact on Facebook, that is associated with reduced psychiatric symptoms.