Temperament and substance abuse in schizophrenia: is there a relationship?

Toward a rational pharmacotherapy of comorbid substance abuse in schizophrenic patients

The prevalence of substance abuse is elevated among schizophrenic patients. When free of illicit substances and sober, substance-abusing schizophrenic patients may have a better prognosis than other frequently hospitalized schizophrenic patients. However, the cost of substance abuse is great in terms of rehospitalization, homelessness, risk of other medical illness, disruption of social and vocational function, exacerbation of symptoms, suicide, and increased health care expenses. Important recent developments in medications for reducing substance abuse in nonschizophrenic populations make it timely to consider factors that might contribute to substance abuse among schizophrenic patients. This review will focus on substances most frequently abused by schizophrenic patients: nicotine, alcohol, cannabis, and psychostimulants. It concentrates on two conceptual foci: "self-medication hypotheses" and "comorbid addiction vulnerability hypotheses". The relationship between these hypotheses and possible pharmacotherapeutic approaches for substance-abusing schizophrenic patients will be considered.

Examining an affect regulation model of substance abuse in schizophrenia. The role of traits and coping

Comorbid substance use disorders occur frequently in schizophrenia with significant detrimental effects to clinical outcome. Unfortunately, attempts to identify factors associated with comorbid substance use disorders (beyond demographic characteristics such as gender) have not been successful. This study examined an affect regulation model of comorbid substance use in schizophrenia with a focus on personality traits and coping. It was hypothesized that maladaptive coping and the traits of negative affect (NA) and disinhibition (DIS), but not trait positive affect (PA), would be associated with greater substance use problems. Thirty-nine patients with schizophrenia or schizoaffective disorder completed measures of personality traits, coping, and negative consequences associated with substance use. Traits were differentially associated with coping in that NA and DIS, but not PA, were associated with maladaptive coping including the use of drugs and alcohol to cope with stress. Alternatively, PA, but not DIS or NA, was related to adaptive coping strategies. Individuals high in NA and endorsing the use of drugs and alcohol to cope reported the greatest number of negative consequences from substance use. This finding held after controlling for gender. These results are consistent with an affect regulation model of substance use and suggest the advantage of examining the role of affect, traits, and coping in understanding comorbid substance use in schizophrenia.

Personality and psychopathology in schizophrenia: the association between personality traits and symptoms

Research has indicated that stable individual differences in personality exist among persons with schizophrenia, and that they likely predate the onset of illness. Little is known, however, about whether individual differences in personality are related to levels of psychopathology. This study tested the hypotheses that levels of Extroversion, Neuroticism, and Psychoticism are associated with symptomatology. Accordingly, measures of these dimensions of personality and of symptomatology were obtained simultaneously for 113 male subjects with schizophrenia or schizoaffective disorder. Next, subjects were characterized as having high or low levels on each personality dimension and their scores on the five components of the Positive Negative Syndrome Scale were compared using multivariate and univariate procedures. Results indicate that extroverted subjects had lower levels of Positive, Negative, and Emotional Discomfort symptoms, and higher levels of Excitement symptoms than introverted subjects. Subjects with higher levels of Neuroticism had higher levels of Positive and Emotional Discomfort symptoms than subjects with lower levels of Neuroticism. No differences in symptoms were found among subjects with higher versus lower levels of Psychoticism. Results suggest individual differences in personality are associated with psychopathology in schizophrenia and may help further explain the heterogeneity widely observed in this disorder.

Temperament and character inventory (TCI) and depression

Although several studies have assessed the relationships between the temperament dimensions of the Cloninger model of personality and depression, little is known about the role played by the character dimensions proposed by the seven-factor model of Cloninger in depression. In this study, the relationships between the Temperament and Character Inventory (TCI) and depression were examined in a sample of 40 major depressive patients and 40 healthy controls. Depressed patients exhibit higher harm avoidance and self-transcendence scores as well as lower self-directedness and cooperativeness scores as compared to healthy controls. However, the three other dimensions do not differ between depressive patients and controls. Among the depressive group, harm avoidance, self-directedness and cooperativeness dimensions are related to the severity of depression as assessed by the Hamilton scale. This study confirms the state dependence of the harm avoidance dimension and suggests a relationship between the character dimensions of the Cloninger model and depression.