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9. Risk factors for suicide completion in major depression: a case-control study of impulsive and aggressive behaviors in men

Author

Dumais, A., Lesage, A.D., Alda, M., Rouleau, G., Dumont, M., Chawky, N., Roy, M., Mann, J.J., Benkelfat, C., and Turecki, Gustavo

Subjects
Men -- Research, Men -- Psychological aspects, Suicidal behavior -- Research, Suicidal behavior -- Psychological aspects, Suicidal behavior -- Risk factors, Major depressive disorder -- Research, Major depressive disorder -- Psychological aspects, Health, Psychology and mental health
Abstract

Objective: Major depression is a major risk factor for suicide. However, not all individuals with major depression commit suicide. Impulsive and aggressive behaviors have been proposed as risk factors for suicide, but it remains unclear whether their effect on the risk of suicide is at least partly explained by axis I disorders commonly associated with suicide, such as major depression. With a case-control design, a comparison of the level of impulsive and aggressive behaviors and the prevalence of associated psychopathology was carried out with control for the presence of primary psychopathology. Method: One hundred and four male suicide completers who died during an episode of major depression and 74 living depressed male comparison subjects were investigated with proxy-based interviews by using structured diagnostic instruments and personality trait assessments. Results: The authors found that current (6-month prevalence) alcohol abuse/dependence, current drug abuse/dependence, and cluster B personality disorders increased the risk of suicide in individuals with major depression. Also, higher levels of impulsivity and aggression were associated with suicide. An analysis by age showed that these risk factors were more specific to younger suicide victims (ages 18-40). A multivariate analysis indicated that current alcohol abuse/dependence and cluster B personality disorder were two independent predictors of suicide. Conclusions: Impulsive-aggressive personality disorders and alcohol abuse/dependence were two independent predictors of suicide in major depression, and impulsive and aggressive behaviors seem to underlie these risk factors. A developmental hypothesis of suicidal behavior, with impulsive and aggressive behaviors as the starting point, is discussed.

Published
2005

11. Biology of elderly suicide

Author

Rifai, A.H., Reynolds, C.F., and Mann, J.J.

Subjects
Suicide -- Physiological aspects, Aged -- Psychological aspects, Serotoninergic mechanisms -- Psychological aspects, Psychology and mental health
Abstract

Most studies of suicide in younger patients have demonstrated significant alterations in the serotonin system. Although a high percentage of completed suicides occur in late-life, to date very few studies of the biology of suicide have focused on this age group. This chapter describe age-related changes in the central nervous system pertinent to the biology of suicide, then reviews port-mortem biological studies of the brains of suicides and suicide attempters. As suicide attempts in the elderly are characterized by the use of violent means, biologic studies of impulsive violence are discussed. Finally we describe data on the effect of degenerative diseases on the serotonin system and the possible link to increased suicidal behavior in affected patients. This review underscores the need for further study of the biology of suicide in the geriatric age group.

Published
1992

17. Heritability of CSF dopamine, serotonin and norepinephrine among baboons

Author

ROGERS, J., COMMUZZIE, A.G., MARTIN, L., MANN, J.J., MANUCK, S.B., and KAPLAN, J.R.

Subjects
Heredity -- Research, Baboons -- Genetic aspects, Cerebrospinal fluid -- Analysis, Animal behavior -- Genetic aspects, Neurochemistry -- Research, Neurotransmitters -- Genetic aspects, Anthropology/archeology/folklore
Abstract

The CNS neurotransmitters dopamine, serotonin and norepinephrine play important roles in the control and expression of behavior. Dopamine is associated with arousal and reward seeking, and norepinephrine with anxiety. Serotonin acts to inhibit behavior, including impulsive aggression. We measured metabolites of these neurotransmitters in the cerebrospinal fluid of 186 pedigreed baboons (Papio hamadryas) drawn from the multigeneration colony maintained at the Southwest Foundation. Quantitative genetic analyses were performed using univariate models, with age, sex, body weight and subspecies as covariates. Individual variation is significantly influenced by genetic variation. The estimated heritability ([h.sup.2]) of HVA (metabolite of dopamine) is 0.34 (p [is less than] 0.03), [h.sup.2] of MHPG metabolite of norepinephrine) is 0.32 (p [is less than] 0.03) and [h.sup.2.] of 5HIAA (metabolite of serotonin) is 0.42 (p [is less than] 0.014). The ratio of 5HIAA/HVA, which may be a better indicator of behavioral tendencies than either HVA or 5HIAA alone, has estimated [h.sup.2] of 0.46 (p [is less than] 0.005). Data from humans and other mammals implicates these neurotransmitters in the control of various behaviors. Field studies show that CSF levels of these neurotransmitters vary across subspecies of baboons that differ in fundamental aspects of social behavior. Our data indicate Papio can be used as a model for genetic studies of individual variation in neurochemistry and behavior. Partial support was provided by a Southwest Foundation Forum grant to A.G.C. and NIH grant P51-RR13986 to J.R.

Published
2001

32. Evidence for the 5-HT hypothesis of suicide: a review of post-mortem studies

Author

Mann, J.J., Arango, V., Marzuk, P.M., Theccanat, S., and Reis, D.J.

Subjects
Serotonin -- Receptors, Self-destructive behavior -- Physiological aspects, Suicide -- Physiological aspects, Serotonin -- Physiological aspects, Health
Abstract

Recent research suggests a link between the brain chemical, serotonin, and the risk for suicide. Traditional psychiatric theory claims that low serotonin levels are associated with depression. Serotonin (also called 5-HT) is metabolized by an enzyme to another substance, 5-hydroxyindoleacetic acid (5-HIAA). Initially, post-mortem studies of the levels of serotonin or 5-HIAA in the brains of suicide victims were carried out to study the biochemistry of depression. Most of those studies found moderately low levels of both serotonin and 5-HIAA. Several later studies have found lower levels of 5-HIAA in the cerebrospinal fluid (which bathes the brain and spinal cord) of psychiatric patients who attempted suicide than the levels in non-suicidal psychiatric patients with similar diagnoses. Studies of suicidal and non-suicidal patients with bipolar disorder do not show differences in 5-HIAA in cerebrospinal fluid. This may be because low cerebrospinal fluid levels of 5-HIAA are already associated with bipolar disorder. The degree of violence used to accomplish suicide seems to be unrelated to serotonin or 5-HIAA levels, although violent suicide attempters have been shown to have increased numbers of 5-HT-2 receptors, structures which are thought to mediate the effects of serotonin. It is not clear why violent behavior is directed inwardly by some people, but it has been suggested that changes in other brain chemicals may influence the direction of violent, impulsive acts. (Consumer Summary produced by Reliance Medical Information, Inc.)

Published
1989

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