Writing about traumas can influence mood and bodily changes. In three studies we researched the influence of writing on affective and physiological changes by measuring electrodermal activity (EDA) during expressive writing sessions and manipulating self-distancing. In Study 1, we randomly assigned 57 participants to write about control or expressive topics using a first-person perspective (I). In Study 2, we assigned 55 participants to write about control or expressive topics using a third-person perspective (She/He). And in Study 3, we compared the effects of perspective (first or third-person) in the data collected in the preceding studies. Across Study 1 and 2 results showed that EDA consistently rose at the beginning of the writing session, reached a plateau, and then rose again upon completing the writing task, irrespective of the writing topic or perspective. While the initial EDA increase seems related to the start of a demanding task, the post-writing increase might signal reward-seeking behavior upon task completion. Results of Study 3 confirmed that EDA increases in the beginning and upon writing completion are magnified by adopting a third-person perspective. These results show that expressive writing and self-distancing have measurable impacts on writers’ electrodermal activity.