Comorbid Main Depressive Dysfunction ADHD - Report Example

The role of comorbid major depressive disorder in the clinical presentation of adult ADHD”—A Critical Review In this 2007 study, Aline G. Fisher and associates examined a group of adults with various forms of attention-deficit/hyperactivity disorder (ADHD) in order to investigate the differences between the substantial minority with co-morbid major depressive disorder (MDD) and the majority who did not suffer from MDD. By comparing the two groups of ADHD patients, the authors hoped to discover some of the ways in which ADHD does and does not differ when present with co-morbid MDD. While their stated goal was a modest one of exploration and evaluation, it can be inferred that they believed that their findings were likely ultimately to facilitate better diagnosis and treatment of adult ADHD. The authors recruited study participants by placing articles in newspapers. Potential participants were examined at a large teaching hospital in southern Brazil; a group of 320 adults of “European descent” with ADHD were chosen by screening interview for further analysis before treatment for their ADHD; those with significant neurological disease, past or present psychosis, or estimated IQ of 70 or below were excluded from the study. Those selected for participation were interviewed using parts of the Portuguese-language K-SADS-E protocol to determine the nature of their past and present ADHD, as well as oppositional defiant disorder (ODD); the protocol used was based on the protocol normally used for adolescents, adjusted only to the extent that the boundary for “childhood” onset of symptoms was moved from age 7 to age 12. Participants were further tested for conduct disorder and anti-social personality disorder using parts of the MINI interview protocol; MDD, anxiety disorders, other lifetime psychiatric disorders, and substance/alcohol abuse problems were identified through interviews using the SCID-IV-R protocol. Participants filled out the self-administered SNAP-IV questionnaire in order to assess the severity of their ADHD and ODD symptoms, and were further interviewed to determine their demographic, social, medical, and educational status. Finally, the results of all these tests were subjected to statistical analysis to determine the impact of MDD on adult ADHD. Participants The authors do not provide a thorough description of their recruitment methods or criteria. In particular, they do not provide any justification for restricting their sample to ADHD sufferers of European descent; in fact, they do not even define “European descent”, which can be a slippery concept in a mixed society like that of Brazil. Further, while the authors state that subjects “were referred in response to information in newspapers [sic] articles”, they give no indication of what information these articles contained, in which newspapers they were published, or who referred subjects to the hospital where they were examined and treated. Accordingly, it is impossible to determine whether any selection bias may have skewed the results of the study. (It is worth noting that the current paper refers to a previous paper, written in 2006 by many of the same authors, for further characterization of the subjects in this study; it is possible that this earlier paper answers these questions.) Method The basic method of this study was to perform extensive interviews and self-assessment (as outlined above) to gather a substantial set of diagnostic and other facts about each participant, then to subject the information gathered to standard statistical methods, including regression testing. Both gender and MDD status were chosen as independent variables, while the various clinical and demographic results of ADHD were chosen as dependent variables. As the authors’ 2006 paper dealt with gender as an independent variable in the chosen group of ADHD patients, the current paper focuses mainly on the effects of MDD. SPSS was used to analyze the statistics, with a significance level of 0.05. The authors’ general approach to gathering and analyzing their statistics appears to be sound; and they clearly differentiate between their actual statistical findings and the implications they draw from these findings. Further, they are careful to highlight areas where their sample may not provide adequate numbers to draw firm conclusions—notably regarding some of the anxiety disorders seen in only a small number of study participants. The fact that the details of previous psychiatric diagnoses and treatments were not included in the information gathered means that some of the authors’ conclusions regarding the failure to diagnose ADHD co-existing with MDD at an earlier age must be taken with a grain of salt; but as the authors point out this limitation themselves and suggest further relevant research, they can hardly be faulted for it. The choice of independent variable for this paper is appropriate, given that the authors’ stated purpose is not primarily to analyze the prevalence of MDD among ADHD sufferers (or vice versa), but rather to examine the implications of MDD as a co-morbid condition with ADHD. It is possible that some form of selection bias may have influenced the proportion of MDD sufferers among the ADHD patients recruited for this study; but it is unlikely that such a bias would strongly alter the effects of MDD revealed by the authors’ analysis. Results and Conclusions Many of the factors measured were essentially identical between the group of ADHD patients with co-morbid MDD and those without MDD. In particular, neither the severity nor the type of ADHD differed between the two groups; neither did income, education, or employment status. Rates of oppositional defiant disorder and conduct disorder were almost exactly the same in both groups. (Those with MDD did have a lower rate of antisocial personality disorder, but the difference was not statistically significant—mostly because of the small number of subjects with this disorder in the sample.) Given the similarity in the nature of ADHD symptoms and severity between those with and without MDD, it was surprising that those in the MDD group had less history of disruption of their educational careers: their rate of grade repetition was somewhat lower, and their rate of suspension or expulsion from school was between one third and one half that of ADHD sufferers without MDD. The rate of prior diagnosis of ADHD in the MDD group was also significantly lower than in the non-MDD group, perhaps at least in part because of their lower incidence of problems in school. Less surprisingly, those with MDD had significantly higher rates of previous psychotherapy and treatment with psychiatric drugs than those without MDD; however, the study did not gather information on the nature of these prior treatments or the diagnoses that led to them. In terms of current diagnoses, patients with MDD were more likely than those without MDD to suffer from social phobia and generalized anxiety disorder. There was no evidence for increased rates of other anxiety disorders, although—as the authors point out—the latter may be an artifact of insufficient sample size rather than a dependable finding. (Panic disorder, in particular, appears to be more common among MDD sufferers in this sample.) The MDD group were less likely to be substance-dependent; in fact, not one of the 81 MDD sufferers was substance-dependent, compared to 29 of the 239 ADHD patients without MDD. The authors note that ADHD patients with MDD were diagnosed with ADHD no earlier than those without MDD, despite the fact that they had a significantly more extensive history of psychiatric treatment. While this may be explained in part by the fact that those in the sample with MDD were less likely to have the kind of educational problems that often lead to ADHD diagnosis, the authors conclude that the lack of earlier ADHD diagnosis despite a greater degree of psychiatric intervention represents a potential failing of the diagnostic system, and an opportunity for improvement in diagnosis and treatment. Summary—Validity and Reliability Although this study’s investigative and analytical techniques appear sound—and thus its results are internally valid—the lack of a full description of the method and criteria used to recruit study participants raises some questions about the external validity of its conclusions. Further, the fact that subjects were recruited only from one region and consisted only of people of “European descent” limits the study’s external validity, even if no other selection bias was introduced. Given the lack of previous research on ADHD in adults, it is impossible to evaluate this study’s convergent validity. The results reported by the authors all seem adequately reliable; possible additional results that did not meet the test of statistical significance (e.g. the greater prevalence of panic disorder among patients with MDD) were not reported. The study was originally designed as a two-factor factorial experiment, with MDD status and gender as independent variables. However, the authors explain that there was no significant interaction between gender and MDD in their initial regression analyses; and thus the project was split into two separate single-independent-variable analyses, one of which is reported in the current paper. As the authors point out, this study was somewhat exploratory in nature; ADHD in adults has not been extensively or adequately studied, and the current study was the first of its type. As such, the authors suggest that further studies with broader samples should be undertaken to clarify the relationship between MDD (and associated anxiety disorders) and ADHD, with particular attention to the possible use of MDD diagnosis as a “warning signal” for ADHD. Given the potential benefit to patients of earlier ADHD diagnosis and treatment, this paper—despite its limitations—may prove to be very useful and important for future psychiatric care of these patients. Read More