Cognitive ability in early adulthood and risk of 5 specific psychiatric disorders in middle age: the Vietnam experience study.

CONTEXT Lower cognitive ability is a risk factor for some forms of psychopathology, but much of the evidence for risk is based on individuals who required specialist care. It is unclear whether lower ability influences the risk of particular patterns of comorbidity. OBJECTIVE To examine the relation between premorbid cognitive ability in early adulthood and the risk of major depression, generalized anxiety disorder (GAD), posttraumatic stress disorder (PTSD), alcohol and other drug abuse or dependence, and comorbid forms of these conditions in midlife. DESIGN Prospective cohort study in which cognitive ability was measured on enlistment into military service at a mean age of 20.4 years and psychiatric disorder was assessed by structured diagnostic interview at a mean age of 38.3 years. SETTING The United States. PARTICIPANTS A total of 3258 male veterans, participants in the Vietnam Experience Study. MAIN OUTCOME MEASURES Major depression, GAD, PTSD, and alcohol or other drug abuse or dependence since enlistment and currently, diagnosed according to the DSM-III. RESULTS Lower cognitive ability was associated with an increased risk of depression, GAD, alcohol abuse or dependence, and PTSD and with some patterns of comorbidity. For a 1-SD decrease in cognitive ability, unadjusted odds ratios (95% confidence interval) for having these disorders currently were 1.32 (1.12-1.56) for depression, 1.43 (1.27-1.64) for GAD, 1.20 (1.08-1.35) for alcohol abuse or dependence, 1.39 (1.18-1.67) for PTSD, 2.50 (1.41-4.55) for PTSD plus GAD, 2.17 (1.47-3.22) for PTSD plus GAD plus depression, and 2.77 (1.12-6.66) for all 4 disorders. Most associations remained statistically significant after adjustment for confounders. CONCLUSIONS Lower cognitive ability is a risk factor for several specific psychiatric disorders, including some forms of comorbidity. Understanding the mechanisms whereby ability is linked to individual patterns of psychopathology may inform intervention.

[1]  E. L. Mortensen,et al.  Childhood IQ in relation to later psychiatric disorder: evidence from a Danish birth cohort study. , 2005, The British journal of psychiatry : the journal of mental science.

[2]  I. Deary,et al.  Mental ability across childhood in relation to risk factors for premature mortality in adult life: the 1970 British Cohort Study , 2007, Journal of Epidemiology & Community Health.

[3]  Ian J Deary,et al.  Locus of Control at Age 10 Years and Health Outcomes and Behaviors at Age 30 Years: The 1970 British Cohort Study , 2008, Psychosomatic medicine.

[4]  Richie Poulton,et al.  Early childhood factors associated with the development of post-traumatic stress disorder: results from a longitudinal birth cohort , 2006, Psychological Medicine.

[5]  M. Nordentoft,et al.  Childhood social environment and risk of drug and alcohol abuse in a cohort of Danish men born in 1953. , 2006, American journal of epidemiology.

[6]  H. L. Williams,et al.  Army tests for assessment of intellectual deficit. , 1957, United States Armed Forces medical journal.

[7]  Laurie T Martin,et al.  Childhood cognitive performance and risk of generalized anxiety disorder. , 2007, International journal of epidemiology.

[8]  Dimitris Fouskakis,et al.  Associations between premorbid intellectual performance, early-life exposures and early-onset schizophrenia , 2002, British Journal of Psychiatry.

[9]  H. Xian,et al.  A twin study of generalized anxiety disorder symptoms, panic disorder symptoms and post-traumatic stress disorder in men , 2001, Psychiatry Research.

[10]  R. Kessler,et al.  Lifetime and 12-month prevalence of DSM-III-R psychiatric disorders in the United States. Results from the National Comorbidity Survey. , 1994, Archives of general psychiatry.

[11]  H. Wittchen,et al.  Recall and dating of psychiatric symptoms. Test-retest reliability of time-related symptom questions in a standardized psychiatric interview. , 1989, Archives of general psychiatry.

[12]  B. Dohrenwend,et al.  Continuing controversy over the psychological risks of Vietnam for U.S. veterans. , 2007, Journal of traumatic stress.

[13]  G. Andrews,et al.  Deconstructing current comorbidity: data from the Australian National Survey of Mental Health and Well-Being , 2002, British Journal of Psychiatry.

[14]  K. Bucholz,et al.  Differential Etiology of Posttraumatic Stress Disorder with Conduct Disorder and Major Depression in Male Veterans , 2007, Biological Psychiatry.

[15]  M. Tsuang,et al.  Genetic and environmental influences on posttraumatic stress disorder, alcohol and drug dependence in twin pairs. , 2000, Drug and alcohol dependence.

[16]  M. Höfler,et al.  Why do people with anxiety disorders become depressed? A prospective‐longitudinal community study , 2000, Acta psychiatrica Scandinavica. Supplementum.

[17]  C. Muntaner,et al.  Socioeconomic position and major mental disorders. , 2004, Epidemiologic reviews.

[18]  I. Deary,et al.  Childhood Mental Ability in Relation to Food Intake and Physical Activity in Adulthood: The 1970 British Cohort Study , 2007, Pediatrics.

[19]  V. Molinari,et al.  Locus of control and its relationship to anxiety and depression. , 1981, Journal of personality assessment.

[20]  Dieter Wagner,et al.  Predicting posttraumatic stress symptoms from pretraumatic risk factors: a 2-year prospective follow-up study in firefighters. , 2005, The American journal of psychiatry.

[21]  I. Deary,et al.  Childhood IQ and all-cause mortality before and after age 65: prospective observational study linking the Scottish Mental Survey 1932 and the Midspan studies. , 2005, British journal of health psychology.

[22]  Richie Poulton,et al.  Depression and Generalized Anxiety Disorder: Cumulative and Sequential Comorbidity in a Birth Cohort Followed Prospectively to Age 32 Years , 2009 .

[23]  E. Nickel,et al.  Validity of the CAGE questionnaire in screening for alcohol dependence in a walk-in (triage) clinic. , 1995, Journal of studies on alcohol.

[24]  Ian J. Deary,et al.  Childhood mental ability and lifetime psychiatric contact: A 66-year follow-up study of the 1932 Scottish Mental Ability Survey , 2002 .

[25]  D I Boomsma,et al.  The co-morbidity of anxiety and depression in the perspective of genetic epidemiology. A review of twin and family studies , 2005, Psychological Medicine.

[26]  D. Lawlor,et al.  Cognitive function in childhood and early adulthood and hospital admission for schizophrenia and bipolar disorders in Danish men born in 1953 , 2007, Schizophrenia Research.

[27]  J. Hoyer,et al.  Generalized anxiety disorder: nature and course. , 2001, The Journal of clinical psychiatry.

[28]  L J Whalley,et al.  Childhood mental ability and smoking cessation in adulthood: prospective observational study linking the Scottish Mental Survey 1932 and the Midspan studies , 2003, Journal of epidemiology and community health.

[29]  K. Kendler,et al.  A population-based twin study of the relationship between neuroticism and internalizing disorders. , 2006, The American journal of psychiatry.

[30]  N. Breslau,et al.  Intelligence and other predisposing factors in exposure to trauma and posttraumatic stress disorder: a follow-up study at age 17 years. , 2006, Archives of general psychiatry.

[31]  J. Stellman,et al.  Post-traumatic stress disorder among American Legionnaires in relation to combat experience in Vietnam: associated and contributing factors. , 1988, Environmental research.

[32]  Peter B. Jones,et al.  Childhood cognitive ability and adult mental health in the British 1946 birth cohort , 2007, Social science & medicine.

[33]  D. Fergusson,et al.  Show me the child at seven II: Childhood intelligence and later outcomes in adolescence and young adulthood. , 2005, Journal of child psychology and psychiatry, and allied disciplines.

[34]  I. Deary,et al.  Childhood mental ability and adult alcohol intake and alcohol problems: the 1970 British cohort study. , 2008, American journal of public health.

[35]  S. Orr,et al.  Lower precombat intelligence is a risk factor for posttraumatic stress disorder. , 1998, Journal of consulting and clinical psychology.

[36]  A. Caspi,et al.  Generalized anxiety disorder and depression: childhood risk factors in a birth cohort followed to age 32 , 2007, Psychological Medicine.

[37]  S. Purcell,et al.  Pretrauma cognitive ability and risk for posttraumatic stress disorder: a twin study. , 2007, Archives of general psychiatry.

[38]  G. Andrews,et al.  Recall of depressive episode 25 years previously , 1999, Psychological Medicine.

[39]  P. Philippot,et al.  Socioeconomic inequalities in depression: a meta-analysis. , 2003, American journal of epidemiology.

[40]  Glyn Lewis,et al.  A longitudinal study of premorbid IQ Score and risk of developing schizophrenia, bipolar disorder, severe depression, and other nonaffective psychoses. , 2004, Archives of general psychiatry.

[41]  M. Mcgeehin,et al.  Postservice mortality in Vietnam veterans: 30-year follow-up. , 2004, Archives of internal medicine.

[42]  M. Tsuang,et al.  Common genetic liability to major depression and posttraumatic stress disorder in men. , 2008, Journal of affective disorders.

[43]  Health status of Vietnam veterans. I. Psychosocial characteristics. The Centers for Disease Control Vietnam Experience Study. , 1988, JAMA.

[44]  R. Bijl P01.66 Current and residual functional disability associated with psychopathology. Findings from the Netherlands mental health survey and incidence study (NEMESIS) , 2000, European Psychiatry.

[45]  A. David,et al.  IQ and risk for schizophrenia: a population-based cohort study , 1997, Psychological Medicine.

[46]  Alison Walker,et al.  Living in Britain : results from the 2001 General Household Survey , 2001 .

[47]  B. Dohrenwend,et al.  The Psychological Risks of Vietnam for U.S. Veterans: A Revisit with New Data and Methods , 2006, Science.