Mary Cannon

Beaumont Hospital, Dublin, Leinster, Ireland

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Publications (150)815.57 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Whilst psychotic experiences are associated with suicidal behaviour in a number of studies the value of psychotic experiences for the prediction of suicidal behaviour and the role of depressive symptoms in this relationship is not clear. We examined the association between psychotic experiences and subsequent suicidal behaviour and examine the role of depressive symptoms in this relationship. Psychotic experiences and depressive symptoms at age 12 and 16 years, and suicidal behaviour at age 16 years were assessed in participants (prospective analysis n = 3171; cross-sectional analysis n = 3952) from a population-based cohort. Psychotic experiences (OR 1.75 95 % CI 1.20, 2.54) and depression (OR 3.97 95 % CI 2.56, 6.15) at 12 years were independently associated with suicidal behaviour at 16 years after adjustment for confounding. There was no evidence that the relationship between psychotic experiences and suicidal behaviour was stronger in participants who were also depressive. A ROC analysis showed that adding information on psychotic experiences to measures of depressive symptoms had hardly any effect on improving prediction of suicidal behaviour (AUC increased from 0.64 to 0.65). Whereas adding a measure of depressive symptoms to the measure of psychotic experiences improved prediction substantially (AUC 0.56-0.65). Psychotic experiences and depression are independently associated with suicidal behaviour although the association with depression is substantially stronger. Psychotic experiences alone are not a strong predictor of later suicidal behaviour and add little to predicting the risk of suicidal behaviour over and above the information provided by depressive symptoms.
    Social Psychiatry 07/2015; 50(12). DOI:10.1007/s00127-015-1086-2 · 2.54 Impact Factor
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    ABSTRACT: This study aimed to examine whether or not sexual minority youth constitute an at-risk group for nonsuicidal self-injury, suicidal ideation or suicide attempts during their emerging adult years. Using data from the Challenging Times Study, a population-based study of psychopathology and suicide in Ireland, analyses were conducted to test the associations between sexual minority status and the odds of any lifetime experience of nonsuicidal self-injury, suicidal thoughts or suicide attempts among Irish youth aged 19-24 years. Sexual minority youth had 6.6-fold (95% CI 1.7-24.7) increased risk of nonsuicidal self-injury, a 5.0-fold (95% CI 1.3-18.3) increased risk of suicidal ideation, a 7.7-fold (95% CI 1.8-32.0) increased risk of suicide intent and a 6.8-fold (95% CI 1.6-27.6) increased risk of a suicide attempt during their lifetime compared to their heterosexual peers. This study shows that emerging adulthood is a period of risk for suicide and nonsuicidal self-injurious behaviour among sexual minority youth. © 2015 Wiley Publishing Asia Pty Ltd.
    Early Intervention in Psychiatry 05/2015; DOI:10.1111/eip.12249 · 1.95 Impact Factor
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    ABSTRACT: Abnormal brain connectivity is thought to have a key role in the pathophysiology of schizophrenia and other psychotic disorders. White matter (WM) abnormalities have been reported in patients with schizophrenia and patients with prodromal syndromes. To our knowledge, no studies have yet reported on WM differences among adolescents who report psychotic experiences, a known vulnerability group for later severe psychopathology, including psychotic illness. To study WM differences using diffusion-weighted imaging (whole-brain and tractography analyses) in adolescents who report psychotic experiences. A population-based case-control study of 28 adolescents 13 to 16 years old who reported psychotic experiences and a matched sample of 28 adolescents who did not report psychotic experiences drawn from a sample of 212 young people recruited from primary schools in North Dublin and Kildare, Ireland. The study dates were 2008 to 2011. High-angular resolution diffusion-weighted imaging data were used to conduct whole-brain WM analysis using tract-based spatial statistics. Based on this exploratory analysis, a tractography-based approach with constrained spherical deconvolution was performed. Compared with control group participants, adolescents who reported psychotic experiences showed WM differences bilaterally in striatal regions in proximity to the putamen (increased fractional anisotropy, P = .01, false discovery rate corrected), and tractography identified significant WM differences bilaterally in the uncinate fasciculus (increased fractional anisotropy in the right [P = .001] and axial diffusivity in the left [P = .01] uncinate fasciculus, respectively). Similar patterns of WM differences between groups survived adjustment for other psychopathology, indicating some specificity for psychotic experiences. Exploratory along-tract analyses showed WM differences between groups in the frontal projections of the right inferior fronto-occipital fasciculus (reduced radial diffusivity in approximately 32% of the tract segment [P ≤ .0001] and increased fractional anisotropy in approximately 16% of the tract segment [P ≤ .0009]). In a population-based study of adolescents reporting psychotic experiences, we found a number of WM differences in the region of the putamen located between the inferior fronto-occipital fasciculus and the uncinate fasciculus and in the left parietal regions that include the fiber bundle of the superior longitudinal fasciculus. These findings suggest that subtle structural changes to WM microstructure are not merely a consequence of disorder but may index vulnerability to psychosis even at a very early age.
    JAMA Psychiatry 04/2015; 72(7). DOI:10.1001/jamapsychiatry.2015.0137 · 12.01 Impact Factor
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    ABSTRACT: Psychotic experiences are far more common in the population than psychotic disorder. They are associated with a number of adverse outcomes but there has been little research on associations with functioning and distress. We wished to investigate functioning and distress in a community sample of adolescents with psychotic experiences. Two hundred and twelve school-going adolescents were assessed for psychotic experiences, mental distress associated with these experiences, global (social/occupational) functioning on the Children's Global Assessment Scale, and a number of candidate mediator variables, including psychopathology, suicidality, trauma (physical and sexual abuse and exposure to domestic violence) and neurocognitive functioning. Seventy five percent of participants who reported psychotic experiences reported that they found these experiences distressing (mean score for severity of distress was 6.9 out of maximum 10). Participants who reported psychotic experiences had poorer functioning than participants who did not report psychotic experiences (respective means: 68.6, 81.9; OR=0.25, 95% CI=0.14-0.44). Similarly, participants with an Axis-1 psychiatric disorder who reported psychotic experiences had poorer functioning than participants with a disorder who did not report psychotic experiences (respective means: 61.8, 74.5; OR=0.28, 95% CI=0.12-0.63). Candidate mediator variables explained some but not all of the relationship between psychotic experiences and functioning (OR=0.48, 95% CI=0.22-1.05, P<0.07). Young people with psychotic experiences have poorer global functioning than those who do not, even when compared with other young people with psychopathology (but who do not report psychotic experiences). A disclosure of psychotic experiences should alert treating clinicians that the individual may have significantly more functional disability than suggested by the psychopathological diagnosis alone. Copyright © 2015 Elsevier B.V. All rights reserved.
    Schizophrenia Research 04/2015; 165(1). DOI:10.1016/j.schres.2015.03.020 · 3.92 Impact Factor
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    ABSTRACT: Objectives Increasing rates of young people not in education, employment or training (NEETs) are a cause of concern both in Ireland and internationally, but little longitudinal research has examined the link between psychiatric disorder in young people and NEET status. Methods The Challenging Times (CT) Study is a longitudinal, population-based study of psychopathology among 212 young Irish people. Clinical interviews were performed at two time points: 12–15 years and 19–24 years. Results NEET status in young adulthood was associated with a sevenfold increased risk of current suicidal ideation. This result was independent of prior adolescent mental disorder. NEET young people had a fourfold increased odds of being diagnosed with a mental disorder in childhood or early adolescence compared with their economically active peers. NEET young people were at an almost threefold increased risk of any mental health disorder a twofold increased risk of anxiety disorder and threefold increased odds of suicide attempts over their lifetime compared with economically active peers. Conclusions NEET young people are at increased risk for mental disorder and suicidal ideation. The association is bidirectional, as prior mental disorder in adolescence appeared to account for much of the association between NEET status and current mental health problems. However, economic inactivity conveys an increased risk for suicidal ideation over and above that due to prior disorder. Our findings provide a compelling economic and societal argument for early intervention and treatment of mental disorder and the importance of vocational interventions for reducing suicide risk in young adults.
    Irish journal of psychological medicine 03/2015; 32(Special Edition 01):155-160. DOI:10.1017/ipm.2014.85
  • M. Clancy · H. Barry · K. Murphy · M. Cannon · D. Cotter ·

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    ABSTRACT: Background There is a lack of epidemiological research on the mental health of young adults in Ireland.Objectives To determine prevalence of psychiatric disorders in a cohort of young Irish adults.Methods The Challenging Times study was a landmark study of the prevalence of psychiatric disorders in adolescents in North Dublin, Ireland: 212 school children aged 12-15 years were recruited through schools and interviewed using the K-SADS semi-structured diagnostic instrument. This cohort was traced again at age 19-24 years (mean age 20.8 years) and interviewed using SCID I & II. Main outcome measures were current and lifetime Axis I and Axis II psychiatric disorders.Results Follow-up rate was 80%. Using a weighted population prevalence analysis 19.8% of the cohort had a current mental disorder, 56.0% had a lifetime mental disorder of whom 28.4% had mood disorders, 27.1% had anxiety disorders, 22.7% had substance use disorders; 25.4% had lifetime multi-morbidity. Cluster A personality disorders were found in 2.3%. Lifetime prevalence of binge-drinking was 75.0%, cannabis use 65% and 17% of young adults had fulfilled criteria for an alcohol use disorder at sometime in their life. Lifetime prevalence of suicidal thoughts/behaviour was 21.1%.Conclusions Lifetime prevalence of psychiatric disorder and substance use were high in this sample of young Irish adults. Mental Health service provision for this age group is a priority. Larger studies of nationally representative samples are needed to inform service development.
    Irish journal of psychological medicine 03/2015; 32(Special Issue 1):79-91. DOI:10.1017/ipm.2014.88
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    ABSTRACT: Background: Maternal infection is a risk factor for schizophrenia but the molecular and cellular mechanisms are not fully known. Myelin abnormalities are amongst the most robust neuropathological changes observed in schizophrenia, and preliminary evidence suggests that prenatal inflammation may play a role. Methods: Label-free liquid chromatography-mass spectrometry was performed on the prefrontal cortex (PFC) of adult rat offspring born to dams that were exposed on gestational day 15 to the viral mimic polyinosinic:polycytidylic acid [poly(I:C), 4 mg/kg] or saline and treated with the atypical antipsychotic drug risperidone (0.045 mg/kg) or saline in adolescence. Western blotting was employed to validate protein changes. Results: Over 1,000 proteins were quantified in the PFC with pathway analyses implicating changes in core metabolic pathways, following prenatal poly(I:C) exposure. Some of these protein changes were absent in the PFC of poly(I:C)-treated offspring that subsequently received risperidone treatment in adolescence. Particularly interesting reductions in the expression of the myelin-related proteins myelin basic protein isoform 3 (MBP1) and rhombex 29 were observed, which were reversed by risperidone treatment. Validation by Western blotting confirmed changes in MBP1 and mitogen-activated kinase 1 (MAPK1). Western blotting was extended to assess the MAPK signalling proteins due to their roles in inflammation, namely phosphorylated MAPK1 and phosphorylated MAPK-activated protein kinase 2. Both were upregulated by poly(I:C) treatment and reversed by risperidone treatment. Conclusions: Overall, our data suggest that maternal inflammation may contribute to an increased risk for schizophrenia through mechanisms involving metabolic function and myelin formation and that risperidone in adolescence may prevent or reverse such changes.
    Developmental Neuroscience 01/2015; 37(1). DOI:10.1159/000368305 · 2.70 Impact Factor
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    ABSTRACT: Objective Neurodevelopmental theories of psychosis highlight the potential benefits of early intervention, prevention, and/or preemption. How early intervention should take place has not been established, nor if interventions based on social learning principles can have preemptive effects. The objective was to test if a comprehensive psychosocial intervention can significantly alter psychotic symptom trajectories during adolescence – a period of heightened risk for a wide range of psychopathology. Method This study was a randomized controlled trial (RCT) of Multidimensional Treatment Foster Care (MTFC) for delinquent adolescent girls. Assessment of psychotic symptoms took place at baseline and then 6, 12, 18, and 24 months post-baseline using a standardized self-report instrument (Brief Symptom Inventory). A second source of information about psychotic symptoms was obtained at baseline or 12 months, and again at 24 months using a structured diagnostic interview (the Diagnostic Interview Schedule for Children [DISC]). Results Significant benefits for MTFC over treatment-as-usual for psychosis symptoms were observed over a 24-month period. Findings were replicated across both measures. Effects were independent of substance use and initial symptom severity, and persisted beyond the initial intervention period. Conclusion Ameliorating non-clinical psychotic symptoms trajectories beginning in early adolescence via a multifaceted psychosocial intervention is possible. Developmental research on non-clinical psychotic symptoms and their prognostic value should be complemented by more psychosocial intervention research aimed at modifying these symptom trajectories early in their natural history.
    Journal of the American Academy of Child & Adolescent Psychiatry 12/2014; 53(12). DOI:10.1016/j.jaac.2014.08.014 · 7.26 Impact Factor

  • 10/2014; 13(3). DOI:10.1002/wps.20170
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    Mary Cannon · Mary C Clarke · David R Cotter ·

    American Journal of Psychiatry 09/2014; 171(9):901-5. DOI:10.1176/appi.ajp.2014.14060749 · 12.30 Impact Factor
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    D Kounali · S Zammit · N Wiles · S Sullivan · M Cannon · J Stochl · P Jones · L Mahedy · S H Gage · J Heron · G Lewis ·
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    ABSTRACT: Background: An argument often used to support the view that psychotic experiences (PEs) in general population samples are a valid phenotype for studying the aetiology of schizophrenia is that risk factors for schizophrenia show similar patterns of association with PEs. However, PEs often co-occur with depression, and no study has explicitly tested whether risk factors for schizophrenia are shared between PEs and depression, or are psychopathology specific, while jointly modelling both outcomes. Method: We used data from 7030 subjects from a birth cohort study. Depression and PEs at age 18 years were assessed using self-report questionnaires and semi-structured interviews. We compared the extent to which risk factors for schizophrenia across sociodemographic, familial, neurodevelopmental, stress-adversity, emotional-behavioural and substance use domains showed different associations with PEs and depression within bivariate models that allowed for their correlation. Results: Most of the exposures examined were associated, to a similar degree, with an increased risk of both outcomes. However, whereas female sex and family history of depression showed some discrimination as potential risk factors for depression and PEs, with stronger associations in the former, markers of abnormal neurodevelopment showed stronger associations with PEs. Conclusions: The argument that PEs are valid markers for studying the aetiology of schizophrenia, made simply on the basis that they share risk factors in common, is not well supported. PEs seem to be a weak index of genetic and environmental risk for schizophrenia; however, studies disentangling aetiological pathways to PEs from those impacting upon co-morbid psychopathology might provide important insights into the aetiology of psychotic disorders.
    Psychological Medicine 09/2014; 44(12):2557-2566. DOI:10.1017/S0033291714000026 · 5.94 Impact Factor
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    ABSTRACT: Background Psychotic experiences are prevalent in community samples and are highly correlated with depressive symptoms. This study aimed to investigate the longitudinal associations between psychotic experiences and depressive symptoms between adolescence and young adulthood. Method Prospective cohort study with a 6 year follow-up in a community sample of 7632 adolescents and young adults. Depressive symptoms were assessed with the Short Moods and Feelings Questionnaire and psychotic experiences with a semi-structured clinical interview at 12 and 18 years. Longitudinal and cross-sectional associations were investigated with regression and structural equation models. Results Depressive symptoms and psychotic experiences were associated at each time-point (12 years r = 0.486 [95% CI 0.457, 0.515]; 18 years r = 0.286 [95% CI 0.233, 0.339]) and there were longitudinal within-phenotype associations (depressive symptoms r = 0.252 [95% CI 0.205, 0.299]; psychotic experiences r = 0.662 [95% CI 0.595, 0.729]). There was an across-phenotype association between psychotic experiences at 12 and depressive symptoms at 18 r = 0.139 [95% CI 0.086, 0.192; p<0.001], but no association between depressive symptoms at 12 and psychotic experiences at 18 r = −0.022 [95% CI −0.032, 0.077; p = 0.891]. Conclusions Longitudinal across-phenotype associations were substantially weaker than cross-sectional associations or within-phenotype longitudinal associations. Whilst psychotic experiences at 12 years were associated with a small increase in depression at 18 years, depression at 12 years was not associated with psychotic experiences at 18 years once across-phenotype cross-sectional and within-phenotype longitudinal associations were accounted for. This suggests that the biological mechanisms underlying depression at this age do not increase subsequent risk of psychotic experiences once they resolve.
    PLoS ONE 08/2014; 9(8):e105758. DOI:10.1371/journal.pone.0105758 · 3.23 Impact Factor
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    ABSTRACT: Purpose: Suicide is a leading cause of death among adolescents. Self-harm is the most important risk factor for suicide, yet the majority of self-harm does not come to the attention of health services. The purpose of this study was to establish the relative incidence of adolescent suicide, hospital-treated self-harm and self-harm in the community. Methods: Annual suicide rates were calculated for 15-17 year-old in the Cork and Kerry region in Ireland based on data from the Central Statistics Office. Rates of hospital-treated self-harm were collected by the Irish National Registry of Deliberate Self-Harm. Rates of self-harm in the community were assessed using a survey of 3,881 adolescents, the Child and Adolescent Self-harm in Europe study. Results: The annual suicide rate was 10/100,000. Suicide was six times more common among boys than girls. The annual incidence rate of hospital-treated self-harm was approximately 344/100,000, with the female rate almost twice the male rate. The rate of self-harm in the community was 5,551/100,000, and girls were almost four times more likely to report self-harm. For every boy who died by suicide, 16 presented to hospital with self-harm and 146 reported self-harm in the community. For every female suicide, 162 girls presented to hospital with self-harm and 3,296 reported self-harm. Conclusions: Gender differences in relative rates of self-harm and suicide are very large, with boys who have harmed themselves at particularly high risk of suicide. Knowledge of the relative incidence of self-harm and suicide in adolescents can inform prevention programmes and services.
    Social Psychiatry and Psychiatric Epidemiology 06/2014; 49(12). DOI:10.1007/s00127-014-0907-z · 2.54 Impact Factor
  • A. Hassab Errasoul · M. Cannon · D. Cotter ·
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    ABSTRACT: Aim 1) to assess compliance with the Data Protection Acts (DPA) by a Department of Psychiatry in a general hospital, 2) to implement measures that are likely to maximize compliance with the hospital data protection policy, 3) to close the audit cycle by assessing the impact of such measures on departmental compliance with the DPA over five months period.Method An individual, anonymised staff questionnaire on data collection practices, procedure of disclosure of data to third parties and previous training on DPA was used to collect information from the department staff. The premises were inspected at different times over a week period using structured checklist. Default points were recorded during each inspection. Post-audit interventions included a mixture of educational interventions and practical solutions. A re-audited took place five months later using the same method.Results The baseline audit demonstrated significant lack of compliance with the DPA among staff members and lack of staff training on the DPA. Following the interventions, staff awareness of the requirements of the act rose which in turn lead to better adherence to recommend practices in data handling and to mean default points dropped significantly. Management of manual files appears to constitute the biggest problem in this audit. Daytime breaks were found to pose higher risk to stored data compared with before and after working hours.Conclusions A combination of educational and practical interventions including training of staff on the DPA results in overall improvement in compliance and reduction in default points. However, management of manual (physical) data proves to be more difficult and hence will need more input.
    Irish journal of psychological medicine 06/2014; 31(02):125-130. DOI:10.1017/ipm.2014.12

  • Schizophrenia Research 04/2014; 153:S214. DOI:10.1016/S0920-9964(14)70619-X · 3.92 Impact Factor

  • Schizophrenia Research 04/2014; 153:S231. DOI:10.1016/S0920-9964(14)70664-4 · 3.92 Impact Factor
  • Nick Stefanis · Mary Cannon · Robin Murray · John McGrath ·

    Schizophrenia Research 04/2014; 153:S77. DOI:10.1016/S0920-9964(14)70249-X · 3.92 Impact Factor
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    ABSTRACT: Psychotic symptoms in the context of psychiatric disorders are associated with poor functional outcomes. Environmental stressors are important in the development of psychosis; however, distress may only be pathogenic when it exceeds an individual's ability to cope with it. Therefore, one interesting factor regarding poor functional outcomes in patients with psychotic symptoms may be poor coping. This paper aimed to address the question whether 1) psychotic symptoms are associated with poorer functioning and 2) whether poor coping moderated the association. In a clinical case-clinical control study of 106 newly-referred adolescent patients with non-psychotic psychiatric disorders, coping was investigated using the Adolescents Coping Scale. Severity of impairment in socio-occupational functioning was assessed with the Children's Global Assessment Scale. Patients with non-psychotic psychiatric disorders and additional psychotic symptoms (N = 50) had poorer functioning and were more likely to use avoidance-oriented coping compared to patients with non-psychotic psychiatric disorders without psychotic symptoms (N = 56). No differences were found with respect to approach-oriented coping. When stratifying for poor/good coping, only those adolescent patients with psychotic symptoms who applied poor coping (i.e. less use of approach-oriented coping styles [OR 0.24, p < 0.015] and more use of avoidance-oriented coping [OR 0.23, p < 0.034]) had poorer functioning. However, these interactions were not significant. Non-adaptive coping and poorer functioning were more often present in adolescents with non-psychotic psychiatric disorders and additional psychotic symptoms. Due to small subgroups, our analyses could not give definitive conclusions about the question whether coping moderated the association between psychotic symptoms and functioning. Improvement of coping skills may form an important target for intervention that may contribute to better clinical and functional outcomes in patients with psychotic symptoms.
    BMC Psychiatry 04/2014; 14(1):97. DOI:10.1186/1471-244X-14-97 · 2.21 Impact Factor

  • Schizophrenia Research 04/2014; 153:S315. DOI:10.1016/S0920-9964(14)70892-8 · 3.92 Impact Factor

Publication Stats

7k Citations
815.57 Total Impact Points


  • 2005-2015
    • Beaumont Hospital
      Dublin, Leinster, Ireland
    • Royal College of Surgeons in Ireland
      • Department of Psychiatry
      Dublin, Leinster, Ireland
    • Niuvanniemi Hospital
      Kuopio, Northern Savo, Finland
  • 2013
    • Columbia University
      New York, New York, United States
  • 2012
    • National University of Ireland, Maynooth
      • Department of Psychology
      Maigh Nuad, Leinster, Ireland
  • 2003
    • London Research Institute
      Londinium, England, United Kingdom
  • 1994-2001
    • Saint John of God Hospitaller Services
      Dublin, Leinster, Ireland
  • 2000
    • University of London
      Londinium, England, United Kingdom
  • 1998
    • University of Nottingham
      • Division of Psychiatry and Applied Psychology
      Nottigham, England, United Kingdom