Definition of Variables: Independent variable 1: The main IV is ambient temperature. The temperature change in the environment will go from 20°c in the control condition, to 25°c in the “heat therapy” (experimental) condition. The experimental condition (25 °c) is compared to a normal (room) temperature rather than a cold temperature. A medical definition of room temperature is from 15 to 25°c (merriam-webster, 2015), thus, the average room temperature of 20°c is used as the normal condition, and the warm condition is 25 degrees. We are choosing not to exceed the 25° mark in order to assure that the room is not uncomfortably warm. **HIJ this is important if you do the therapy, but 25 can probably be considered uncomfortably hot. It may get even a bit more complex, because in therapy, one may wants to figure out what the individually relevant temperature is for the person. Again, I would tie the warmth to specific situations (e.g., stress buffering, social predictability)** Independent variable 2: Participants BMI. BMI of 18.5 -24.9 is the classification for being normal weight (NIH, 2015). BMI of 24.5 and over is overweight classification. **Interesting, but why this one?** Dependent variable: sociality and attitude to social contact with others. Sociality is operationalized by ratings on Likert scale questions regarding ones closeness to friends or family and ones willingness to increase social contact with others. This is a prospective cohort quasi-experimental design operating in a clinical trial setting. A quasi- experiment was chosen since the independent variable of weight is a naturally occurring variable. The assignment to treatment groups will be based of participant’s weight. A cut off score of normal vs. overweight will be identified and acts as the basis of our assignment of participants to groups. ![Table][1] Participants in the experimental groups will undergo “heat” therapy (room temperature of 25°c), once a week for 6 weeks. Participants in the control group will continue with traditional interpersonal therapy. The study will take place in the normal place of therapy for the patient, and their therapist will continue to run their sessions as per usual. The researchers have control over the temperature in the room, and of administrated self-reported pre-test and post-test questionnaires that measure progress in sociality. Participants: The target population is people who are currently diagnosed with depression and reports symptoms of social withdrawal. Participants will be recruited through an opportunity sample. We will contact therapist in psychiatric facilities that can ask their patients if they would like to take part in the study. Participants should be currently enrolled in interpersonal therapy. The study is restricted to female participants only, all in the age range of 20-30 in order to assure that they are in similar stages of physical health and are equally receptive to ambient heat. In total, 20 participants will be recruited, 5 people in each group. For each participant added to an experimental group (experiment group 1 or experiment group 2), a matched participant (pair matching) will be assigned into the corresponding control group (control group 1 or control group 2), in order to eliminate confounding variable. Participants will be matched on the basis of BMI and age. The total number of participants recruited is based on a power analysis with G*Power (Faul et al., 2007) with an alpha of 0,05 and power of 0,80 and an effect size of 0.63 (recorded from a meta-analysis on the impact of interpersonal therapy on treating depression (Cuijpers et al., 2011)). We added 1 participant to the 19 that were originally suggested by G*power because pair matching requires an even number of participants. **HIJ ok. clear enough** [1]: http://%3Ca%20href=%22http://tinypic.com?ref=2rfr5ma%22%20target=%22_blank%22%3E%3Cimg%20src=%22http://i61.tinypic.com/2rfr5ma.png%22%20border=%220%22%20alt=%22Image%20and%20video%20hosting%20by%20TinyPic%22%3E%3C/a%3E [2]: http://tinypic.com/r/2rfr5ma/8