The data were analysed using Hierarchical Linear Modeling (HLM) using HLM6 (Raudenbush, Bryk, Cheong, & Congdon Jr., 2004). Hierarchical linear modeling allows for variance in outcome variables to be analysed at multiple hierarchical levels. The data here contained a two level hierarchical structure with Level 1 being the within-person variation (e.g. daily patterns in the number and type of hassles experienced and in the mood and coping response of participants) and Level 2 being the between-person variability (e.g.
condition, baseline depression, baseline stress and alexithymia scores). Level 1 variables were centered around the grand mean. The Level 2 variable, condition, was entered uncentered.
In order to explore the moderating effects of the additional Level 2 variables (baseline depression, baseline stress and alexithymia) on writing, a median split was performed on baseline scores obtained for these data to produce two groups for each variable (e.g. high/low alexithymia, high/low depression, high/low stress). Two separate HLM data files were produced for each Level 2 variable so data could be analysed for each high/low group independently. The final stage saw each high/low group split further into expressive writing and control conditions. Separate HLM data files were produced within each high/low group for both writing conditions and Level 1 analysis was repeated. This allowed for comparisons to be made between the writing conditions for each high/low group.
The hierarchical linear model was designed to run so that the main effect of writing condition on mood/coping outcome variables could be observed simultaneously with cross-level interactions of writing condition on the daily hassles-mood/coping relationship.
As a result, the different research questions for this study were answered in one model.
The model then required examination of the different component parts to extract data relevant to the separate research hypotheses. The first step explored whether there was a main effect of writing condition on mood/coping whilst the second step required
examination of the cross-level interactions between writing condition and the daily hassles-mood/coping relationship.
In order to do this, the day-to-day within-person effects of daily hassles on the mood and coping (Level 1 variables) were modelled, together with the impact of writing condition (Level 2 variable) on mood and coping. Finally, in order to observe the effects of the moderating (Level 2) variables (baseline depression, baseline stress and alexithymia) on the writing condition-mood/coping associations (Step 1) and the cross-level interactions between writing condition and daily hassles-mood/coping associations (Step 2) the analysis above was repeated for each of the separate high/low data files for each of the three potential moderating variables. The general form for the model equation is below:
Level 1: γij = β0j + β1 (daily hassles) + rij Level 2: β0 = γ00 + γ01 (writing condition)
β1 = γ10 + γ11 (writing condition)
In this model, γ00 indicates the mean level of the mood or coping variable, and γ01 (writing condition) indicates the extent to which this average is influenced by the writing condition (the main effect). Similarly, γ10 indicates the average size of the relationship between daily hassles and the mood/coping variables, and γ11 (writing condition) indicates the extent to which that relationship is moderated by (or conditional on) writing condition.
For ease of interpretation, output derived from the model will be broken down into the component interactions detailed above and subsequent analysis will be presented under the appropriate sub-heading for each of the study’s hypotheses. Analysis will be reported for both Time 1 (baseline) and Time 2 (2-month follow-up).
In addition, a series of repeated measures ANOVAs for a mixed design were performed using the scale scores from the Time 1 and Time 2 DAS-21 measure, in order to provide additional information about the relationships between time and writing condition for each variable. These results will be reported under main effects of writing condition on mood/coping variables.
RESULTS 3.1 Overview
The primary two aims of the current research were to investigate the effect of writing condition (GDP, control) on a number of mood (negative, positive, daily mood rating, stress score) and coping (maladaptive, adaptive, positive reframing, acceptance, humour, religion) outcome variables. It was expected that individuals who engaged in expressive writing would experience more negative mood than controls immediately following writing but that this trend would be reversed at follow-up such that expressive writers would be expected to show less negative mood than controls. In addition, it was expected that expressive writers would show greater use of adaptive coping strategies and less use of maladaptive strategies than controls.
A third aim of this research was to consider whether the relationship between daily hassles and mood/coping variables is moderated by writing condition. For instance, it was expected that expressive writers would experience negative mood in response to daily hassles than participants in the control condition. In addition it was expected that expressive writers would utilise more adaptive coping strategies and less maladaptive coping strategies in response to daily hassles as compared to controls.
The final three supplementary aims of this research were to investigate the impact of moderating variables (baseline depression, stress, alexithymia) on both the writing condition-mood/coping relationship but also on the interaction of writing condition on the daily hassles-mood/coping association. It was expected that individuals who are high in stress or high in depression would benefit more from expressive writing than participants who score low on baseline measures of depression or stress (e.g. showing less negative mood either as a main effect of writing and in response to daily hassles at Time 2). In addition, it was expected that alexithymia might moderate the impact of writing although it was unclear at the outset in which direction this might be.
The results section is divided into seven main areas in order to answer the research questions described above: data preparation, main effects of writing on mood/coping, impact of writing on daily hassles-mood/coping relationship, moderating impact of high/low depression, moderating impact of high/low stress and moderating impact of alexithymia. The chapter will conclude with a summary of the findings.