Participants in this group will receive a problem-solving intervention for suicide prevention in a face-to-face format. The intervention will consist of 6 sessions, approximately 90 minutes in duration each, once a week, in a group format, in person.

Participants in this group will receive the intervention described in a teleconference call format, with the same duration, contents, and structure.

Participants in this group will receive the intervention described adapted to be administered through a smartphone app, with equivalent duration, content, and structure (approximately 90 minutes to complete each of the 6 modules).

Participants in this group will receive usual care. Usual treatment will include individual and group psychotherapy and/or psychiatric medication as determined by the health professionals they are currently consulting, whether in public or private facilities.

The intervention will include training in the components of the problem-solving model and other behavioral and cognitive skills such as detecting warning signals, monitoring mood, relaxation techniques, self-reinforcement, strategies for acting in crisis situations, engaging in enjoyable activities, mindfulness meditation techniques, or strategies for reframing irrational thoughts. It will be developed from the problem-solving model (D'Zurilla and Nezu, 1982) and will reference the indicated prevention program for depression (Vázquez et al., 2015), which has shown efficacy in reducing depressive symptoms and preventing the onset of depression episodes (Otero et al., 2015; Vázquez et al., 2013), with results on symptomatology maintained at 8 years (López et al., 2020); and the indicated prevention intervention that demonstrated efficacy in reducing suicide risk (Xavier et al., 2019).

Suicidal ideation will be assessed using the Suicidal Ideation Scale (SSI; Beck et al., 1979), a semi-structured scale of 19 items with an internal consistency (Kuder-Richardson coefficient [KR-20]) of .89 and an inter-rater reliability (k) of .83.

Aditionally, the severity of ideation and suicidal behavior over the last month will be assessed using the Columbia Scale for assessing suicide risk (C-SSRS; Posner et al., 2011). It consists of a semi-structured interview with good convergent and discriminant validity and high sensitivity (100.0%) and specificity (99.4%) for the classification of suicidal behavior; the ideation intensity subscale showed a Cronbach's alpha of .73-.95.

Hopelessness will be assessed with the Beck Hopelessness Scale (HS; Beck et al., 1974), a self-administered instrument of 20 items with a range from 0 to 20. Higher scores mean higher hopelessness. It has an internal consistency (Kuder-Richardson 20 [KR-20]) of .93.

These variables will be assessed using a hetero-administered questionnaire, developed ad hoc for this study, following the recommended criteria in the Clinical Practice Guideline for the Prevention and Treatment of Suicidal Behavior (Grupo de Trabajo de la Guía de Práctica Clínica de Prevención y Tratamiento de la Conducta Suicida, 2012/2020). This questionnaire will include information on: sex, age, marital status, living arrangements, rural/urban setting, education level, main activity, family monthly income, characteristics of suicidal ideation (e.g., potential plans, access to lethal means, intent to die, previous suicide attempts); present/past risk factors (e.g., risk factors related to psychological and psychiatric problems, family history of suicidal behavior and mental disorder, history of physical abuse or sexual abuse); and health and psychosocial stress factors (e.g., presence of chronic illness, financial problems).