Peer Influence and Non-Suicidal Self-Injury in Adolescence

157 Pages·2014·1.33 MB·English

PEER INFLUENCE AND NON-SUICIDAL SELF-INJURY IN ADOLESCENCE:
EXPLORING THE ROLE OF CO-RUMINATION
by
SARAH M. LLOYD

A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE OF MASTER OF ARTS
in
THE FACULTY OF GRADUATE STUDIES
Master of Arts in Counselling Psychology

We accept this thesis as conforming to the required standard

…………………………………………
Joan S. Kimball, PhD., Thesis Supervisor

…………………………………………..
Derrick Klaassen, PhD., Thesis Supervisor

…………………………………………..
Jennifer Muehlenkamp, PhD., External Examiner

TRINITY WESTERN UNIVERSITY
February 2014
©Sarah M. Lloyd
ii

ABSTRACT
The main purpose of this study was to investigate the relationship between co-rumination
and non-suicidal self-injury (NSSI) in a community sample of adolescents. Analysis of
the data from 92 adolescent self-injurers, 51 female and 41 male, indicated that there was
a significant, positive correlation of small effect size between adolescents’ level of co-
rumination and their frequency of self-injury in the past year. When genders were
examined separately, this positive correlation of small effect size remained significant
solely for male participants. Contrary to expectations, co-rumination failed to moderate
the relationship between depression and NSSI frequency, and stressful life events failed
to moderate the relationship between co-rumination and NSSI frequency. Results from
further post-hoc analyses and related research on peer socialization suggest possible
reasons for these results and future research avenues. The strengths, contributions, and
clinical implications of this study are also discussed.
Keywords: Non-suicidal self-injury; co-rumination; adolescents; depression;
stressful life events
iii

PREFACE
This research was approved by Trinity Western University’s Research Ethics Board (File No.
12G03) and was funded by the Social Sciences and Humanities Research Council for Canada
(Graduate Scholarship - Master's; Award No.: 766-2009-0280).
iv

TABLE OF CONTENTS
ABSTRACT ........................................................................................................................ ii
PREFACE .......................................................................................................................... iii
TABLE OF CONTENTS ................................................................................................... iv
LIST OF TABLES ............................................................................................................. ix
LIST OF FIGURES ........................................................................................................... xi
ACKNOWLEDGEMENTS .............................................................................................. xii
CHAPTER I: INTRODUCTION ......................................................................................... 1
Definition of Terms .................................................................................................. 4
CHAPTER II: LITERATURE REVIEW ............................................................................ 5
Nonsuicidal Self-Injury ............................................................................................ 5
Prevalence of NSSI. ..................................................................................... 6
NSSI and distress. ...................................................................................... 10
Functions of NSSI. ..................................................................................... 11
Anti-suicide. ................................................................................... 12
Self-punishment. ............................................................................ 12
Sensation-seeking. ......................................................................... 13
Interpersonal influence. .................................................................. 13
Interpersonal boundaries. ............................................................... 13
Anti-dissociation. ........................................................................... 14
Affect regulation. ........................................................................... 14
v

Explanatory models of NSSI ..................................................................... 16
Experiential avoidance model. ....................................................... 16
Four function model. ...................................................................... 18
Emotional cascade model. ............................................................. 21
Co-Rumination ....................................................................................................... 25
What is co-rumination? .............................................................................. 26
Co-Rumination, friendship quality, and affective distress ......................... 28
Co-rumination and NSSI in Adolescents ............................................................... 34
Does co-rumination moderate the relationship between NSSI and
depression? ................................................................................................. 34
Is co-rumination directly linked with NSSI? ............................................. 36
The Current Study .................................................................................................. 40
Research Design ..................................................................................................... 41
Single Time Point Survey Design. ............................................................. 41
Participants ............................................................................................................. 41
Sample Size ................................................................................................ 41
Inclusion and exclusion criteria ................................................................. 42
Characteristics ............................................................................................ 42
Procedure ............................................................................................................... 43
Student recruitment, class presentations, and questionnaire administration.43
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Offers to school administration. ................................................................. 45
Measures ................................................................................................................ 45
Demographic information. ......................................................................... 46
Depression .................................................................................................. 46
Co-rumination ............................................................................................ 47
Non-suicidal self-injury ............................................................................. 48
Peer NSSI ................................................................................................... 49
Stressful life events .................................................................................... 49
Screening of the Data ............................................................................................. 50
Reliability of Research Measures .......................................................................... 52
CHAPTER IV: RESULTS ................................................................................................. 54
Descriptive Statistics .............................................................................................. 54
Description of NSSI participants ............................................................... 54
Analysis Results ..................................................................................................... 59
Correlation. ................................................................................................ 59
Hypothesis 1: Co-Rumination positively correlated with the
frequency of NSSI in adolescents. ................................................. 59
Hierarchical multiple regression ................................................................ 60
Hypothesis 2: Co-rumination moderates the relationship between
depression and the frequency of NSSI in adolescents. .................. 60
vii

Hypothesis 3: Stressful life events moderates the relationship
between co-rumination and the frequency of NSSI in adolescents.62
Post-Hoc Analyses ................................................................................................. 65
Gender, age, and peer NSSI ....................................................................... 65
Gender differences. ........................................................................ 68
The impact of whether peers engage in self-injury on the relationship
between co-rumination and self-injury ...................................................... 73
CHAPTER V: DISCUSSION ............................................................................................ 75
Prevalence of NSSI ................................................................................................ 76
Characteristics of Self-Injuring Participants .......................................................... 80
Co-Rumination and NSSI ...................................................................................... 82
Co-rumination positively correlated with NSSI in adolescents ................. 82
The relationship between co-rumination and self-injury in male
participants. .................................................................................... 85
Co-rumination and stressful life events in male self-injurers. ....... 86
Co-rumination, peer self-injury, and adolescent self-injury ...................... 87
Co-rumination as moderator variable ........................................................ 88
Limitations ............................................................................................................. 91
Strengths and Contribution .................................................................................... 95
Clinical Implications .............................................................................................. 97
REFERENCES ................................................................................................................ 101
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Appendix A .......................................................................................................... 124
Appendix B .......................................................................................................... 125
Appendix C .......................................................................................................... 128
Appendix D .......................................................................................................... 129
Appendix E .......................................................................................................... 130
Appendix F ........................................................................................................... 131
Appendix G .......................................................................................................... 132
Appendix H .......................................................................................................... 133
Appendix I ........................................................................................................... 135
Appendix J ........................................................................................................... 138
Appendix K .......................................................................................................... 141
Appendix L .......................................................................................................... 143
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LIST OF TABLES
Table 1: Cronbach’s Alpha for Research Measures for the all Participants and
Separately for Self-Injuring Participants ............................................................ 53
Table 2: Demographic Variables of Participants who Engaged in NSSI in the Past Year55
Table 3: Range, Means and Standard Deviations for Measures by Gender in Self-Injuring
Participants (N = 92) .......................................................................................... 57
Table 4: Correlations Between the Study Variables (N = 92) ........................................... 58
Table 5: Hierarchical Regression Analysis for Gender, Depression, Co-Rumination, and
Depression X Co-Rumination Predicting Adolescent NSSI (N = 92) ................. 63
Table 6: Coefficients for Final Model in Hierarchical Multiple Regression Analysis for
Gender, Depression, Co-Rumination, and Depression X Co-Rumination
Predicting Adolescent NSSI (N = 92) ................................................................. 64
Table 7: Hierarchical Regression Analysis for Gender, Co-Rumination, Stressful Life
Events and Co-Rumination X Stressful Life Events Predicting Adolescent NSSI
(N = 92) ............................................................................................................... 66
Table 8: Coefficients for Final Model in Hierarchical Multiple Regression Analysis of
Gender, Co-Rumination, Stressful Life Events and Co-Rumination X Stressful
Life Events Predicting Adolescent NSSI (N = 92) .............................................. 67
Table 9: Hierarchical Regression Analysis for Co-Rumination, Gender and Co-
Rumination X Gender Predicting Interpersonal Independent Stressful Life
Events (N = 92) ................................................................................................... 71
x

Table 10: Coefficients for Final Model in Hierarchical Multiple Regression Analysis of
Co-Rumination, Gender and Co-Rumination X Gender Predicting Interpersonal
Independent Stressful Life Events (N = 92) ........................................................ 72