Examining The Overlap Of ADHD And Bipolar Scales In Assessment

Hyperactivity in attention-deficit/hyperactivity disorder (ADHD) refers to excessive motor activity, impulsivity, and restlessness.

Mania is a feature of bipolar disorder marked by elevated mood and heightened energy/activity levels.

ADHD hyperactivity and manic symptoms like psychomotor agitation, racing thoughts, and impulsivity conceptually converge. Thus measures of hyperactivity in ADHD may tap similar underlying phenomena as mania rating scales intended to index separate conditions.

Barden, E. P., Polizzi, C. P., Vizgaitis, A. L., Bottini, S., Ergas, D., & Krantweiss, A. R. (2023). Hyperactivity or mania: Examining the overlap of scales measuring attention-deficit/hyperactivity disorder and bipolar spectrum disorders in an assessment context. Practice Innovations, 8(2), 102–115. https://doi.org/10.1037/pri0000202

Key Points

1. Measures of ADHD symptoms overlap considerably with measures of bipolar/mania symptoms, which can lead to diagnostic confusion.
2. Self-report measures of ADHD and bipolar/mania symptoms were strongly intercorrelated in a sample of adults seeking ADHD assessment.
3. Bipolar/mania symptoms accounted for unique variance in ADHD symptoms beyond symptoms of inattention and hyperactivity.
4. Hyperactivity and impulsivity symptoms of ADHD explained the most variance in bipolar spectrum symptoms.
5. Multimodal assessment, beyond self-report measures alone, is critical for accurate diagnosis of ADHD and bipolar spectrum disorders.

Rationale

Attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder or manic episodes can manifest with overlapping symptoms, including distractibility, impulsivity, hyperactivity, and racing thoughts. However, clear differentiation is imperative for optimal treatment (Barden et al., 2023).

While ADHD persists across situations and time, mania symptoms fluctuate episodically with significant impairment (Brus et al., 2014). Further, mania includes grandiosity not typical in ADHD (Skirrow et al., 2012).

Though self-report questionnaires offer assessment efficiency, research indicates substantial item content similarities and limitations distinguishing these conditions (Newson et al., 2020). Still, few studies have directly analyzed the relationship between specific ADHD and bipolar measures.

Investigating these associations in adults seeking help for ADHD can strengthen diagnostic clarity and measurement-guided care (Barden et al., 2023).

Method

The study was a quantitative analysis of archival assessment data from adults seeking ADHD assessment at two U.S. outpatient clinics.

Participants completed the following scales:

• Conners’ Adult ADHD Rating Scale–Self-Report: Long Version (CAARS-S:L)
  • Self-report questionnaire assessing ADHD symptoms
  • Includes scales measuring inattention, hyperactivity, impulsivity, emotional dysregulation
• Behavior Assessment System for Children – Third Edition (BASC-3)
  • Valid self-report measure of behavioral and emotional functioning
  • Includes Mania content scale measuring mania symptoms
• Millon Clinical Multiaxial Inventory – Fourth Edition (MCMI-IV)
  • Widely used self-report inventory of personality patterns and psychopathology
  • Specific scale utilized – Bipolar Spectrum assessing bipolar symptoms

Sample

119 adults seeking ADHD assessment (mean age 22 years); 52% female; 75% white; 91% had 12+ years education. Around 22% eventually diagnosed with ADHD; 5% bipolar disorder.

Statistical Analysis

Bivariate Pearson correlations, stepwise linear regressions (cross-validated with hierarchical regressions).

Results

As hypothesized, the bipolar and ADHD self-report measures were strongly intercorrelated (rs .43 to .74), suggesting they tap similar constructs.

The MCMI-IV Bipolar Spectrum Scale was most strongly associated with CAARS-S:L Impulsivity (r = .55) and Hyperactivity scales (r = .58). The BASC-3 Mania Scale was very highly correlated with ADHD Hyperactivity measures (rs .70 to .75) and total ADHD symptoms (r = .74), suggesting substantial overlap with behavioral symptoms.

When controlling for shared variance, bipolar/mania symptoms explained unique variance in ADHD symptoms, supporting study hypotheses. Specifically, the BASC-3 Mania Scale accounted for over half the variance in CAARS-S:L total ADHD symptoms (54%).

Additionally, the CAARS-S:L Hyperactivity Scale was consistently uniquely related to BASC-3 Mania scores in regression analyses. In line with the hypotheses, hyperactivity, and impulsivity symptoms accounted for 39% of the variance in bipolar spectrum symptoms on the MCMI-IV.

Insight

This study provides compelling evidence that self-report measures frequently used to assess ADHD and bipolar disorders—even a specific mania scale—share substantial conceptual overlap and are intertwined psychometrically.

Most critically, the BASC-3 Mania Scale exhibited extremely high correlations (rs ≥ .70) with ADHD symptom measures, calling into question whether commonly used mania scales effectively distinguish between manic and ADHD symptoms.

Further, bipolar/mania symptoms accounted for more than half the variance in total ADHD symptoms on the CAARS-S:L, and behavioral ADHD symptoms (hyperactivity, impulsivity) accounted for nearly 40% of variance in bipolar spectrum symptoms on the MCMI-IV.

These robust predictive relations likely reflect the behavioral and cognitive similarity of ADHD and mania/bipolar symptoms like high energy, racing thoughts, and impulsivity.

In assessment contexts, individuals with clinically elevated ADHD or bipolar symptoms on self-report inventories will likely have concurrent elevations across both types of measures.

Relying solely on self-report questionnaires could, therefore, result in inaccurate diagnostic uncertainty between the disorders or comorbidities. Using multiple assessment modes will be essential for differential diagnosis.

Future research should continue elucidating transdiagnostic processes linking ADHD and bipolar symptoms to optimize measurement and intervention.

Clinically, when elevated bipolar symptoms present alongside ADHD concerns or vice versa, further evaluation ruling out the alternative diagnosis will strengthen diagnostic clarity and allow patients to receive appropriately tailored treatments.

Strengths

This study has several notable strengths:

1. The use of a real-world clinical sample seeking ADHD assessment bolsters the study’s ecological validity and accentuates the relevance of findings for applied practice settings. Diagnostic clarity is imperative when assessments have tangible patient impacts.
2. The examination of multiple well-established self-report measures—the CAARS-S:L for ADHD, BASC-3 Mania Scale, and MCMI-IV Bipolar Scale—within one high-risk sample provides a robust test of the associations between ADHD and bipolar symptom representation on common rating scales.
3. The use of dimensional, rather than categorical, conceptualizations of psychopathology to analyze the correlations and predictive overlap between ADHD and bipolar symptom measures has greater validity based on current research.
4. The combination of bivariate correlational and multiple regression analyses allowed for rigorous quantification of the relationships among variables at distinct levels of analysis—both in terms of interconnectedness and unique predictive capacity. The cross-validation between stepwise and hierarchical regression models also strengthens the validity of analytic conclusions.
5. The study’s focus on adults seeking ADHD assessment uniquely extends research on the clinical measurement challenges distinguishing ADHD and bipolar disorders, which, despite recognition in childhood samples, has been understudied in adults.

Limitations

However, some limitations temper the conclusions that can be drawn:

1. The small sample size (N = 119) poses analytic restrictions, attenuates statistical power to detect smaller effects, and limits external validity and generalizability of findings. Replication in larger, more diverse samples is needed.
2. As archival clinical data, there was variability in which measures participants completed, reducing comparison sample sizes between measures. Standardized administration will improve consistency and rigor.
3. The predominantly white (75%), educated (91% had 12+ years), young adult sample (mean age 22 years) narrows generalizability. Testing across wider demographics could reveal assessment issues in other groups.
4. The inherent limitations of using subjective self-report measures also apply. Biases like social desirability, impaired recall, or insight could distort responses. Multimodal assessment should complement self-reports.
5. Data were archival assessments, preventing experimental causal inference between measures. Researchers could manipulate the presentation of ADHD and bipolar symptoms to evoke contrasting self-reports.

Implications

This study carries noteworthy implications for psychological and psychiatric assessment and diagnosis:

1. Clinicians should carefully rule out bipolar disorder or manic symptoms before diagnosing someone with ADHD, especially if they are an adult seeking an ADHD evaluation. Additional interviews and observations are important when the diagnosis is unclear.
2. Using multiple evaluation methods beyond just questionnaires is vital to accurately tell the difference between ADHD and bipolar disorder across age groups. People endorsing high levels of symptoms on one type of evaluation will likely score high on the other as well because the measures overlap so much. Relying on only one method can lead to the wrong diagnosis or combination of diagnoses.
3. Knowing that ADHD and bipolar disorder questionnaires interrelate so strongly can prevent false alarms during testing. Otherwise, confusion could happen if an ADHD-focused evaluation unexpectedly shows high bipolar or manic scores, or vice versa. Assessors need to consider this potential entanglement when explaining results.
4. The significant overlap between ADHD and bipolar measures suggests they relate to some of the same behavioral and thought patterns, separate from diagnostic labels. Research is needed to clarify the underlying similarities. This knowledge could improve treatments targeting those shared tendencies.
5. The findings connect research on the difficulty distinguishing ADHD from early bipolar disorder in children versus adults. Considering differences in when symptoms start and how they progress over time may help better differentiate the disorders.

References

Primary reference

Barden, E. P., Polizzi, C. P., Vizgaitis, A. L., Bottini, S., Ergas, D., & Krantweiss, A. R. (2023). Hyperactivity or mania: Examining the overlap of scales measuring attention-deficit/hyperactivity disorder and bipolar spectrum disorders in an assessment context. Practice Innovations, 8(2), 102–115. https://doi.org/10.1037/pri0000202

Other references

Brus, M. J., Solanto, M. V., & Goldberg, J. F. (2014). Adult ADHD vs. bipolar disorder in the DSM-5 era: A challenging differentiation for clinicians. Journal of Psychiatric Practice, 20(6), 428–437. https://doi.org/10.1097/01.pra.0000456591.20622.9e

Newson, J. J., Hunter, D., & Thiagarajan, T. C. (2020). The heterogeneity of mental health assessment. Frontiers in Psychiatry, 11, Article 76. https://doi.org/10.3389/fpsyt.2020.00076

Skirrow, C., Hosang, G. M., Farmer, A. E., & Asherson, P. (2012). An update on the debated association between ADHD and bipolar disorder across the lifespan. Journal of Affective Disorders, 141(2-3), 143–159. https://doi.org/10.1016/j.jad.2012.04.003

Keep Learning

Here are some thought-provoking discussion questions about this research a college class could explore:

1. How might limitations in the awareness, recall, or communication of internal experiences influence responses on self-report measures of conditions like ADHD and bipolar disorder? What assessment methods could help corroborate or clarify self-reported symptoms?
2. Could the high degree of overlap between ADHD and bipolar self-report measures suggest they tap dimensional processes that cut across discrete diagnostic categories? Might this support a shift toward more transdiagnostic models of psychopathology? What are the pros and cons of conceptualizing mental health dimensionally versus categorically?
3. What developmental, biological, psychosocial, or contextual factors might help distinguish ADHD and bipolar pathology? When might a comorbid presentation accurately reflect an individual’s clinical presentation?
4. How might confirmation biases, binary thinking, or cultural assumptions around diagnostic categories influence providers interpreting elevated scores across ADHD and bipolar measures? What safeguards protect against premature diagnostic closure?
5. How might findings apply to conditions beyond ADHD and bipolar disorders that have symptomatic overlap? What responsibility do test developers have to minimize item redundancy across measures?