Predictors of suicidality across the life span: The Isle
of Wight study
A. Pickles
1
*, A. Aglan
2
, S. Collishaw
3
, J. Messer
3
, M. Rutter
3
and B. Maughan
3
1
Biostatistics, Health Methodology Research Group, Faculty of Medicine and Human Sciences, University of Manchester, Manchester, UK
2
Division of Clinical Psychology, Faculty of Medicine and Human Sciences, University of Manchester, Manchester, UK
3
MRC Social Genetic and Developmental Psychiatry Centre, King’s College London Institute of Psychiatry, London, UK
Background. Data from a representative community sample were used to explore predictors of lifetime suicidality
and to examine associations between distal adolescent and more proximal adult risks.
Method. Data are from a midlife follow-up of the Isle of Wight study, an epidemiological sample of adolescents
assessed in 1968. Ratings of psychiatric symptoms and disorder, relationships and family functioning and adversity
were made in adolescence ; adult assessments included lifetime psychiatric history and suicidality, neuroticism and
retrospective reports of childhood sexual abuse and harsh parenting.
Results. A wide range of measures of childhood psychopathology, adverse experiences and interpersonal difficulties
were associated with adult suicidality ; associations were particularly strong for adolescent irritability, worry and
depression. In multivariate analyses, substantial proportions of these effects could be explained by their association
with adult psychopathology and neuroticism, but additional effects remained for adolescent irritability and worry.
Conclusions. Factors of importance for long-term suicidality risk are evident in adolescence. These include family
and experiential adversities as well as psychopathology. In particular, markers of adolescent worry and irritability
appeared both potent risks and ones with additional effects beyond associations with adult disorder and adult
neuroticism.
Received 28 May 2009 ; Revised 8 October 2009 ; Accepted 12 October 2009 ; First published online 26 November 2009
Key words : Adolescent risk factors, depression, irritability, longitudinal, worry.
Introduction
Suicidality is a pressing international health problem;
completed suicide is currently one of the main causes
of premature mortality worldwide and attempted
suicide occurs up to 20 times more frequently than
completed suicide (Gunnell & Middleton, 2003 ; WHO,
2004). Epidemiological estimates for lifetime preva-
lence of suicide attempts and deliberate self-harm
range from 750 to 5930 per 100 000 (Welch, 2001).
Findings from past studies document significant as-
sociations between suicidal ideation, plans and at-
tempts (Kessler et al. 1999), underscoring the need for
risk studies to address the full spectrum of suicidal
phenomena, with passive thoughts of death and com-
pleted suicide representing extremes on a spectrum of
risk (Bridge et al. 2006).
Extensive evidence has confirmed that psycho-
pathology is central to the initiation and repetition of
suicidal behaviour in adulthood (Fombonne et al.
2001 ; Fergusson & Woodward, 2002). Depression and
substance use disorders carry the best replicated risks.
More recently, investigators have reported that an-
xiety disorders may also be implicated (Sareen et al.
2005 ; Boden et al. 2007). Significant associations have
been reported between co-morbid psychiatric dis-
orders and suicidal behaviour with evidence of in-
creasing risks of serious suicide attempts associated
with increasing number of disorders (Beautrais et al.
1996b ; Hawton et al. 2003). Personality measures such
as neuroticism have also been found to be associated
with risk at all points of the suicidal spectrum from
ideation to completion (Beautrais et al. 1999 ; Fer-
gusson et al. 2000 ; Brezo et al. 2006).
In addition to these proximal adult risks, long-term
longitudinal studies highlight links with more distal
risk factors, including psychopathology (Neeleman
et al. 1998 ; Sourander et al. 2009) and poor family
functioning in childhood (Fergusson et al. 2000 ;
McGee et al. 2001), interpersonal difficulties in
* Address for correspondence : Professor A. Pickles, Department of
Biostatistics, Section of Epidemiology and Health Science, Stopford
Building, University of Manchester, Oxford Road Manchester
M13 9PT, UK.
(Email : andrew.pickles@manchester.ac.uk)
Psychological Medicine (2010), 40, 1453–1466. f Cambridge University Press 2009
doi:10.1017/S0033291709991905
ORIGINAL ARTICLE

adolescence (Johnson et al. 2002) and exposure to
childhood physical and sexual abuse (CSA) (Beautrais
et al. 1996a ; Fergusson et al. 1996). These have shown
considerable prognostic power, especially among
men (Sourander et al. 2009). A limitation of many past
longitudinal investigations, however, has been the
lack of a developmental framework for considering
associations among these distal and more proximal
risks. It is plausible, for example, that some early
adversities pose a direct increase in risk for suicidal
behaviour, whereas others function indirectly, in-
fluencing exposure to risk or protective factors in
adult life. Current evidence suggests that effects of
maladaptive parenting may be in the second cat-
egory, contributing to risk for interpersonal difficult-
ies in adolescence that in their turn play a pivotal
role in the development of suicidal behaviour
(Johnson et al. 2002). Personality and temperamental
characteristics, by contrast, may both contribute to
interpersonal difficulties in adolescence and pose a
long-term risk for psychopathology (Caspi, 2000).
Indeed, difficult temperament has been shown to
predict several proximal mediators of suicidality in-
cluding depression and stressful events (Windle,
2004).
Prospective findings from the Christchurch study
showed that whereas effects of early family dysfunc-
tion and CSA were largely mediated by mental health
problems and exposure to stressful life events in ado-
lescence and early adulthood, personality measures
such as neuroticism were independently predictive of
suicidality (Fergusson et al. 2000). Such findings argue
the need for longitudinal investigations to consider the
mediating and potentially confounding effects of fac-
tors in a range of risk domains in predicting lifetime
suicidality.
This paper examines these issues in the Isle of
Wight study, a unique epidemiological sample first
assessed in the 1960s (Rutter et al. 1970) and since
followed to midlife. We are able to combine an
assessment of psychopathology from age 16 to 45
years with a rich set of both prospectively and
retrospectively assessed risks including: (a) childhood
adversities ; (b) adolescent psychiatric symptoms
and disorders ; (c) adolescent relationship indicators ;
(d) temperament and personality characteristics.
Childhood adversities include family adversities,
physical abuse and CSA. Adolescent disorders include
minor depression, anxiety, conduct disorder and
teacher-reported hyperactivity. Adolescent relation-
ship indicators include negative relationships with
parents and difficulties with siblings and with peers.
Finally, temperament and personality characteristics
include adolescent worry and irritability and adult
neuroticism.
Subjects and method
Sample
Full surveys of a 2-year cohort of Isle of Wight children
(all those born between 1 September 1953 and
31 August 1955) were undertaken in 1964–1965 (at
ages 9–10 years) and again in 1968–1969, at ages 14–15
years (Rutter et al. 1976). Eligible children were ident-
ified from local education and health authority re-
cords. The study cohort included all age-eligible
children with home addresses on the island, but ex-
cluded the small group who attended private schools
(approximately 6% of the child population). With the
exclusions shown in Fig. 1, this adolescent sample was
the target of a follow-up assessment in midlife (ages
44–45 years). A total of 56 adolescent participants had
died by the time of follow-up; of these, 13 were non-
natural deaths but only four were recorded as suicide.
In this paper, we analyse the adolescent and midlife
data from the 2226 participants who survived to mid-
life.
The Isle of Wight Study – adolescence (1968–1969)
The adolescent studies used a multi-method two-
phase approach combining population questionnaire
and administrative data with intensive investiga-
tions of selected subsamples. The population screen
measures included administrative records (attend-
ance at child guidance clinics, appearance before the
juvenile court or placement in long-term residential
care during the previous year), parent and teacher
behaviour questionnaires (Elander & Rutter, 1996) and
group reading and IQ tests developed by the National
Foundation for Educational Research (see Rutter et al.
1970 for details) to identify those at high risk for psy-
chiatric and/or educational problems. Response rates
were high; teacher and parent behavioural ques-
tionnaires were completed for 97% and 83% of the
sample respectively and educational test data were
available for 92%. All adolescents scoring above
selected cut-offs on any screen instrument were selec-
ted for intensive study along with a random compari-
son group (approximately one in 12 of all children in
the screen population). Response rates at the intensive
phase were 90% of parents/caretakers, 98% of ado-
lescents and 97% of teachers.
The Isle of Wight Midlife Follow-up Study (1998–2000)
The two-phase design of the adolescent studies was
repeated in adulthood; the original screen sample was
mailed questionnaires while those intensively studied
in adolescence were assessed by questionnaire and by
in-depth life-course interview. Study members were
traced using telephone book, electoral register, family
1454 A. Pickles et al.