This open trial will test a new technology-supported blended intervention, mobile Social Interaction Therapy by Exposure (mSITE), that targets social engagement in consumers with serious mental illness.

Social isolation is common in serious mental illness and has a profound negative impact on recovery. This study evaluates a new technology-supported blended intervention, mobile Social Interaction Therapy by Exposure (mSITE), that targets social behavior, and it also validates several new techniques for measuring social behavior. mSITE blends brief in-person psychotherapy with context-triggered mobile smartphone intervention and remote telephone coaching. The investigators will conduct an open trial of mSITE, evaluating whether the intervention leads to clinically significant changes in the frequency of social interactions. The investigators will also determine the dose of app plus remote coaching necessary to achieve this effect, by evaluating change at 12, 18, or 24 weeks. If found to be effective, a scalable intervention that reduces social isolation in serious mental illness would have significant personal, societal, and economic impact.

Inclusion Criteria:

1. Voluntary informed consent to participate and capacity to consent;
2. Age 18 to 65;
3. DSM-5 diagnosis of schizophrenia, schizoaffective, bipolar I disorder or major depression with history of psychosis based on a SCID-5 interview and available medical record review;
4. Minimum level of social avoidance defined by a score of ≥ 2 on the Scale for the Assessment of Negative Symptoms (SANS) asociality item;
5. ≥ 6th grade reading level on the Wide Range Achievement Test-4 Reading subtest (to read therapy workbook).

Exclusion Criteria:

1. Prior CBT in the past 2 years;
2. Greater than moderate disorganization on the PANSS (P2- Disorganization item >5);
3. DSM-5 alcohol or substance dependence in past 3 months based on the SCID;
4. Level of care required interferes with outpatient therapy (e.g., hospitalized; severe medical illness)
5. Unable to adequately see or manually manipulate a phone;
6. Resident of an integrated housing facility that also provides treatment services.

Per terms of the award, participant-level data will be uploaded to the NIMH Data Archive (NDA).

Data will be uploaded according to NDA standard data submission periods. These periods are currently twice each year.

Data access is outlined in the current NDA Policy.