Diagnostic Limitations in Isabella's Case: Insomnia, Anxiety, and Depression

Patient Presentation and Initial Diagnosis

Isabella is a 29-year-old woman who presented to her general practitioner with a primary complaint of difficulty sleeping. She also expressed concerns about work-related stress and her general well-being. She completed the Depression Anxiety Stress Scales questionnaire (Lovibond, 1995) as part of her clinical evaluation. According to her verbal reports, Isabella has difficulty falling asleep and finds it difficult to relax. She worries about work problems during non-working hours, and her insomnia has led to complaints of decreased work performance.

In addition to insomnia, Isabella reports that most of the time she feels tired and irritable. She experiences difficulty concentrating and making decisions. She believes her work performance has declined as a result of these problems, and she reports that her overall well-being is suffering. Based on these presentations and her DASS results, her general practitioner diagnosed her with primary insomnia associated with work stress.

The GP's diagnostic reasoning was primarily based on Isabella's DASS questionnaire scores. Her scores on the Depression and Anxiety scales fell within the normal range, whereas her score on the Stress scale was in the severe range. This pattern of results appeared to support a primary insomnia diagnosis rather than an anxiety disorder or mood disorder. However, as discussed below, this single assessment tool may not have captured the full clinical picture.

Diagnostic Limitations and Alternative Considerations

Several alternate diagnoses warrant consideration in Isabella's case. One strong possibility is Generalized Anxiety Disorder (GAD). Although Isabella's Anxiety scale score on the DASS was in the normal range, this result alone should not exclude GAD from consideration. First, Isabella has reported a lifelong pattern of excessive worry about her school and work performance, as well as about her family and minor everyday concerns. These worries have persisted throughout and beyond childhood, whereas her insomnia is a recent phenomenon. It is possible that the insomnia is secondary to an underlying GAD that became more pronounced when Isabella received her recent promotion.

A second critical concern is that the DASS may not be a completely accurate evaluation tool for all anxiety and depression presentations. The GP relied on only one self-report metric, but research shows that different assessment tools can yield different results. One study found that only medium-sized correlations exist between different tests for depression, anxiety, and post-traumatic stress disorder (Einsle, 2010, p. 584). Additionally, patients may underreport symptoms on self-report measures due to perceived stigma surrounding mental illness. Best practices recommend using multiple screening tests rather than relying on a single instrument (Janeway, 2009, p. 36).

A third reason to consider alternative diagnoses is that Isabella reports difficulty concentrating and making decisions. These are recognized features of major depressive disorder and dysthymia according to the Diagnostic and Statistical Manual for Mental Disorders IV (2000), yet these symptoms are not directly assessed by the DASS. Difficulty concentrating is also a feature of GAD. While these symptoms may be secondary to insomnia, they may equally reflect an underlying depression or anxiety disorder.

Several factors make GAD a more probable alternative diagnosis than major depressive disorder or dysthymia. Isabella reports five of the six diagnostic symptoms of GAD, whereas she lacks some critical symptoms of major depressive disorder, such as persistently low mood and anhedonia (loss of pleasure in previously enjoyed activities). Most importantly, Isabella clearly exhibits excessive worry and anxiety—likely not attributable to an underlying mood disorder—which is an essential diagnostic feature of GAD.

Etiological Theories and Treatment Implications

Two potentially competing theories address the etiology of Isabella's symptoms. One theory posits that her insomnia and stress result from an organic or endogenous disorder, while another suggests her symptoms are reactive—arising in response to increased work demands following her promotion. However, these theories are not mutually exclusive. It is possible that both organic and reactive factors contribute to her presentation.

Research on neurological conditions demonstrates this interaction; for example, studies comparing rheumatoid arthritis and multiple sclerosis found that disease type independently predicts whether depression will develop, suggesting that direct neurological mechanisms partially cause mood disturbances even when external stressors are present (Holden, 2011, p. 1). Similarly, an organic or endogenous factor may underlie Isabella's insomnia and stress, even if they are partly triggered by her increased workload.

An additional theory is that Isabella's insomnia may be caused by a primary psychiatric disorder, such as major depression, dysthymia, or an anxiety disorder. The DASS questionnaire does not evaluate several key components of major depressive disorder as defined by DSM-IV. For instance, the DASS does not assess loss or slowing of motor function, low energy, poor concentration, or the quality of social support networks—all important in evaluating major depressive disorder. These omissions suggest that major depressive disorder and dysthymia should not be ruled out on the basis of DASS results alone.

The distinction among these diagnoses is critically important for determining appropriate treatment. A diagnosis of primary insomnia due to work stress might warrant treatment with a sedative medication such as zolpidem or a benzodiazepine. However, if an anxiety disorder underlies or is comorbid with Isabella's insomnia, benzodiazepine treatment might be appropriate. Conversely, if major depressive disorder or dysthymia is present, an antidepressant medication such as a selective serotonin reuptake inhibitor (SSRI) may be the optimal treatment. Moreover, research indicates that early, mild presentations that may be subclinical according to DSM-IV criteria have a strong potential to develop into severe disorders, making aggressive early treatment potentially cost-effective and preventive (Kessler, 2003, p. 1117).

A critical consideration is that Isabella's insomnia may be comorbid with another condition that remains undetected by her verbal report and DASS questionnaire results. The two most likely possibilities are major depressive disorder and generalized anxiety disorder. This distinction is essential because treatment options differ substantially. For major depressive disorder, treatment typically involves antidepressant medication and/or cognitive-behavioral therapy. For generalized anxiety disorder, treatment more often involves benzodiazepines and/or cognitive-behavioral therapy. As argued above, GAD is more likely than major depressive disorder in Isabella's case, but comprehensive evaluation—using DSM questionnaires, additional anxiety and depression measures, and detailed verbal assessment—is required to clarify the diagnostic picture.

Comorbidity, Assessment Gaps, and Psychopathology Models

Given the available information, cognitive-behavioral therapy (CBT) appears to be a well-supported recommendation for Isabella's case. CBT would provide therapeutic intervention while also helping clarify what, if any, pharmacological treatments are needed. While some research suggests CBT may not be effective in certain cases, closer examination of these studies reveals that apparent lack of effectiveness was often due to early termination of treatment rather than inherent ineffectiveness (Belleville, 2011, p. 318). There is little evidence of negative effects from CBT, making it a low-risk intervention.

An additional factor warranting investigation is the possibility of substance use. Neither the DSM nor the DASS questionnaires directly assess whether substance use may exacerbate or precede anxiety, depression, or stress disorders. Additional assessment tools, such as the Cannabis Expectancy Questionnaire, which directly addresses substance use patterns, could provide valuable information (Connor, 2010).

Isabella's verbal report emphasizes that her inability to relax and her indecisiveness have been detrimental to her well-being. It remains unclear whether treating her insomnia alone will improve her sense of well-being. While better sleep may help her relax and make decisions more effectively, sleep-focused treatment might have limited impact on these secondary symptoms.

According to major models of psychopathology, addressing Isabella's insomnia without treating her other symptoms is unlikely to be ideal. Psychoanalytic models attribute pathology to unresolved internal conflict, requiring insight-oriented therapy. Cognitive and behavioral models emphasize learned negative thinking and behavioral patterns, requiring new ways of thinking and responding. Humanistic models focus on incomplete self-actualization, addressed through empathy and unconditional positive regard. All three frameworks, when applied to Isabella's case, suggest that comprehensive psychotherapy is warranted in addition to sleep-focused interventions. Even if her current presentation is mild, it may worsen over time, making preventative psychological treatment potentially cost-effective and beneficial for long-term well-being (Kessler, 2003, p. 1117).

An important theory regarding anxiety in Isabella's case concerns meta-worry—worry about worrying itself. According to Wells and Carter (1999, p. 585), holding positive beliefs about the usefulness of worry is a characteristic feature of generalized anxiety disorder. Isabella appears to hold such beliefs; in her verbal report, she mentioned that she believes her worrying has contributed to her academic success and helps her cope with challenges. According to the theoretical model proposed by Wells (1999, p. 585), this meta-worry pattern can lead to increased frequency and generalization of worry, ultimately resulting in pathological worry and anxiety. This pattern in Isabella provides additional evidence that she should be evaluated for generalized anxiety disorder rather than receiving a diagnosis of insomnia alone, and that comprehensive psychological treatment may be beneficial.