The objective of the present project is to study the differential effectiveness of three brief self-applied via the Internet interventions for mild to moderate depression: a global protocol composed of several therapeutic components (psychoeducation, cognitive restructuring, behavioral activation, positive psychology, and relapse prevention), a protocol just based on behavioral activation (BA), and a protocol just based on positive psychology (PP). The purpose is to know the specific contribution of each therapeutic components in the treatment of depression.

Depression is one of the most important health problems worldwide, which generates important costs, both from the economic point of view as from the social and personal one. If not properly treated, it may become chronic and therefore interferes significantly in all areas of operation. Hence, one of the most important challenges within this scope is the design of new ways to apply treatments in a way that maximizes its therapeutic efficiency. Information and Communication Technologies (ICTs) have proven their utility as they are very useful in order to provide help to all those in need. It is a field of study very novel which will become more important in the short term. Several internationally renowned research groups have launched self-applied treatment programs through the Internet in order to address this issue. Results obtained so far are consistent and promising, and show these treatments as effective. However, these treatments have different therapeutic components and it is important to identify the specific contribution of each of them. Therefore, the objective of the present project is to study the differential effectiveness of three brief self-applied via the Internet interventions for mild to moderate depression: a global protocol composed of several therapeutic components (psychoeducation, cognitive restructuring, behavioral activation, positive psychology, and relapse prevention), a protocol just based on behavioral activation (BA), and a protocol just based on positive psychology (PP). A minimum of 192 participants diagnosed with mild to moderate depression symptoms will be randomly assigned to one of the three experimental conditions: an Internet-based global protocol composed of several therapeutic components (n=64); a Internet-based protocol based on BA (n=64), and an Internet-based program based on PP (n=64). Our hypothesis is that it is possible to progress and improve in the treatment of depression through intervention strategies applied through the Internet.

Inclusion Criteria:

• 18-65 years old.
• Having mild to moderate depression symptoms.
• Providing written, informed consent.
• Being able to understand and read Spanish.
• Having daily access to the Internet in their natural environment.

Exclusion Criteria:

• Being diagnosed a severe mental disorder (people with the following mental disorders will be excluded from the study: schizophrenia, bipolar disorder and personality disorders from clusters A and B).
• Being diagnosed an alcohol and/or substance dependence disorder.
• The presence of high suicidal risk.
• A medical disease or condition which prevent the participant from carry out the psychological treatment.
• Receiving another psychological treatment while the study is still ongoing.
• The increase and/or changes in the medication of participants receiving pharmacological treatment during the study.