Dysthymia, major depression, and double depression among individuals receiving substance abuse treatment ()
1. INTRODUCTION
Mood disorders have been described as the world’s most disabling condition by the Global Burden of Disease study [1]. These disorders exhibit distinct patterns that may represent different subtypes. For example, compared to major depressive disorder, dysthymia is characterized by milder symptomatology. However, individuals with dysthymia have reported greater cumulative symptoms, more suicide attempts, hospitalizations, and social impairment than individuals with episodic major depression [2]. Dysthymia is a common mood disorder that has a lifetime prevalence rate of approximately 6% in the general population [3,4] and 22% in outpatient mental health settings [5]. Dysthymic disorder is defined as a low-grade and chronic depression that lasts for at least 2 years for adults Diagnostic and Statistical Manual of Mental Disorders IV-TR [6].
A ten-year prospective, naturalistic follow-up study was conducted comparing the course of depression among outpatients with double depression (DD) (that is, dysthymia comorbid with major depression), pure dysthymic disorder, and major depressive disorder [7]. Findings supported data from a previous study [2], whereby outpatients who experienced double depression and pure dysthymia indicated significantly higher levels of depression at the ten-year follow-up compared to outpatients with major depressive disorder. Furthermore, the individuals with double depression and pure dysthymic disorder spent a greater amount of time during the 10 year follow-up period of the study meeting criteria for a mood disorder compared to outpatients with major depressive disorder.
Considering these results on length of illness of dysthymia, the severity of dysthymic disorder and DD when compared to major depressive disorder (MDD), and the different patterns of these mood disorders among outpatients, it is important to examine the impact of dysthymia, major depression, and double depression in other clinical populations, particularly among individuals who abuse substances. There is an elevated comorbidity rate between mood disorders and substance use disorders [2, 8-10], and this co-occurrence has a serious negative impact on individuals’ lives. A research study compared 86 dysthymic disorder individuals to 39 episodic major depressive disorder individuals, and reported that a significantly greater proportion of dysthymic clients experienced a lifetime of history of substance abuse or dependence than the episodic MDD clients [2].
In another study [11] examined the individual characteristics and mental health factors of dysthymic and non-dysthymic clients. One hundred and eight three medical records were selected for the study and 48% of these records were of individuals with dysthymic disorder. Results indicated that dysthymic clients were more likely to be male, older individuals, who reported higher levels of alcohol dependence, lower quality of life, and higher number of previous substance abuse treatments than individuals without dysthymia.
Despite the elevated comorbidity between mood disorders and substance use disorders, there are only a limited number of studies examining the impact of dysthymic disorder on substance abuse. In addition, there is a paucity of data comparing dysthymia with other mood disorders in this population. Thus, the aim of this study was to compare dysthymic disorder with double depression and major depressive disorder among individuals attending a substance abuse treatment center, and examine the following individual characteristics and mental health factors: 1) age; 2) gender; 3) alcohol dependence; 4) drug dependence; 5) number of suicide attempts; 6) number of suicide attempts under the influence; 7) perceived quality of life; 8) number of previous mental health treatments; and 9) number of previous substance abuse treatments. The findings from this study may provide useful information to practitioners regarding the assessment and treatment of individuals who may suffer from a dual diagnosis of a mood disorder and a substance use disorder. Two important questions are raised in this study about dysthymia, major depression, and double depression in a substance abuse population: 1) what is the nature of their comorbid relationship with substance use disorders? and 2) what are the individual characteristics (age and gender) and mental health factors (e.g. drug dependence, alcohol dependence, quality of life) that distinguish dysthymia, double depression, and major depressive disorder among individuals who abuse substances?
2. METHOD
2.1. Participants
This is an exploratory study that involved the review of the biopsychosocial assessment section of medical charts. A total of 336 charts of consecutively admission to a residential substance abuse treatment agency were reviewed; this agency is located in southeastern Florida. Agency personnel conducted the review and entered the data. The clients attending this agency come from different geographical areas across the United States, and have diverse economic backgrounds. Institutional Review Board (IRB) approval was obtained prior to data collection. Upon admission to this agency, all clients complete multiple biopsychosocial assessment forms which include information concerning: sociodemo-graphic characteristics (self-reports of gender and age); selfreports of number of previous mental health and substance abuse treatments; self-reports of number of suicide attempts and number of suicide attempts under the influence; assessment of dysthymic disorder, major depressive disorder, and alcohol and drug dependence scores as measured by the Millon Clinical Multiaxial Inventory (MCMI-III) [12]; and assessment of perceived quality of life as measured by the Quality of Life Inventory. Charts were excluded from the review if the assessment forms were incomplete or had substantial missing data from the aforementioned sections or instruments. All clients at this agency were 18 years old or older.
2.2. Measures
2.2.1. Millon Clinical Multiaxial Inventory (MCMI-III)
The MCMI-III is a widely used 175 items self-report questionnaire that was utilized to measure dysthymic traits, major depressive disorder traits, and alcohol and/or drug dependence symptoms. This instrument has been shown to have good psychometric properties [12-14], and has been used as an assessment tool in several studies of individuals who abuse drugs [13,15,16]. The MCMI-III consists of 28 scales: 4 scales assess the patients’ validity and response style (Validity Index, Disclosure, Desirability, and Debasement), 14 scales assess personality disorders, and 10 scales assess clinical syndromes, including dysthymia, major depression, alcohol dependence and drug dependence.
The MCMI-III has a Debasement scale that measures an individual’s tendency to devalue himself or herself by presenting more emotional problems than are likely upon a clinical evaluation. The MCMI-III also contains a Desirability scale that measures an individual’s tendency to appear socially attractive or emotionally well. Similar to the scoring of the mental disorders discussed above, scores above 75 on the Debasement scale indicate that individuals may be seriously distorting their symptomatology to make it seem worse than it is. Scores of less than 65 on the Desirability scale indicate that individuals are likely to be giving answers that neither exaggerate nor minimize their symptomatology in an effort to produce an answer that will please the assessor. The MCMI-III scores the traits and symptoms as follows: 1) a score of 85 or higher is indicative of all the traits and symptoms for a given mental disorder at a clinical level; 2) scores between 75 and 85 indicate the presence of traits and symptoms associated with the disorder, below clinical levels; and 3) a score of less than 75 is considered to lack clinical significance. For the purposes of this study, five study groups were created: No Dysthymia, Dysthymia, No Major Depression, Major Depression, and Double Depression (See Table 1 for study group placement criteria).
Alcohol or Drug dependence was assessed by using the Alcohol Dependence and Drug Dependence scales of the MCMI-III. The Alcohol dependence measures a history of alcoholism in which an individual has unsuccessfully attempted to overcome the problem unsuccessfully and has experienced considerable impairment in family and/or work place functioning. The Drug Dependence scale assesses the individual’s recurrent or recent history of drug use, including evidence of impulsivity and an inability to manage consequences of drug using behavior. A score of 75 or higher suggests dependence for both scales.
2.2.2. Quality of Life Inventory (QOLI)
The QOLI [17] is an instrument developed to assess life satisfaction specifically for use in clinical populations. It measures global quality of life based on multiple satisfaction ratings in 16 defined domains. Respondents rate the importance of a given domain to their overall happiness and satisfaction (0 = not at all important; 1 = important; 2 = very important), and then rate how satisfied they are in a given area (–3 = very dissatisfied; 3 = very satisfied). A weighted satisfaction rating is then obtained by multiplying the importance and satisfaction ratings, with scores ranging from –6 to +6. Then, after excluding all the weighted satisfaction scores with an importance score of 0, the mean of the weighted satisfaction ratings is computed. This process ensures that only life areas the respondent considers important are included in his or her quality of life score.
The literature indicates that the QOLI has strong psychometric properties [18-20]. A study used the QOLI in a study with three nonclinical samples and three clinical samples [20]. The internal consistency and 1-month test-retest reliability were high with values of 0.75 or greater across all the samples. A more recent study reported an internal consistency of the total satisfaction
scale of 0.85 in a clinical sample of 217 clients referred for treatment of anxiety and depressive disorders [18]. In addition, the QOLI has demonstrated strong convergent and divergent validity as well as good construct and criterion-related validity [18-20].
2.2.3. Sociodemographic Characteristics and Other Variables
The sociodemographic characteristics and other mental health variables for this study were obtained from the agency’s medical records. These variables included self-report of gender, age and race. Participants also indicated whether they had been in an alcohol or drug treatment program before (yes or no). If the respondents answered yes, they identified the number of times they had attended an alcohol/drug treatment program. In addition, they were asked whether they had received mental health counseling/treatment in the past. If the respondents indicated yes, they were asked for the number of times they received this treatment. Suicide attempt was assessed by asking respondents whether they had ever attempted suicide (yes or no). If yes, they were asked to indicate how many times they attempted suicide and if the suicide attempts were under the influence of alcohol and/or drugs.
2.3. Data Analysis
Continuous variables were analyzed using independent samples t-tests. For the t-tests, separate estimates of variance were used, rather than pooled, when the variances differed significantly between groups. Categorical variables were analyzed utilizing chi-square tests. Yates correction was used in chi-square tests on 2 × 2 tables. An alpha level of 0.05 was used. All tests were two tailed. The number of respondents in some analyses varied due to missing data.
3. RESULTS
Of the 336 medical records reviewed, 139 (41.4%) met the dysthymia criteria for this study, 15 (4.5%) met the MDD criteria, and 47 (14%) met the DD criteria. The
Table 1. Study diagnostic groups with MCMI-III score placement criteria.
overall sample had a mean age of 36.7 years (SD = 11.8), 62.8% were male (n = 211), 85.7% were White (n = 287), 9.3% were Black (n = 31), 1.5% were Latino (n = 5), 0.9% were Asian (n = 3), and 2.7% were Other (n = 9). In addition, approximately 55% (n = 182) reported having either one or two previous mental health treatments, and 49% (n = 164) reported having either one or two previous substance abuse treatments. Eight four percent of the sample (n = 278) indicated no suicide attempt, while 15% of the sample (n = 50) indicated having either 1 or 2 suicide attempts, and 0.6% (n = 2) reported having 3 suicide attempts. Approximately 90% of the sample (n = 293) reported no suicide attempts under the influence and 10% (n = 34) indicated having 1 or 2 suicide attempts under the influence of drug or alcohol.
3.1. Bivariate Analyses
3.1.1. Dysthymia
Table 2 presents the bivariate analyses of the individual characteristics and mental health factors of the dysthymic vs. non-dysthymic clients. Clients with dysthymia differed from non-dysthymics on gender (X2 [1, N = 336] = 82.82, p < 0.001), reflecting that a greater proportion of the former group were male. Out of 139 clients reporting dysthymia, 91.4% were males (n = 127) while 57.4% of non-dysthymic clients were female (n = 113). The groups also differed on age (t [336] = –2.10, p < 0.05) whereby those with dysthymia were older than non-dysthymic clients.