• Affective lability
• Attention Deficit/Hyperactivity Disorder
• Bipolar Disrder
• Borderline Personality Disorder
• Cyclothymic Disorder

Introduction: Attention Deficit/Hyperactivity Disorder (ADHD) is a Neurodevelopmental Disorder that onsets during the childhood and persists into adulthood in two-thirds of the cases. The comorbidity with other psychiatric disorders such as Bipolar Disorder (BD) and Borderline Personality Disorder (BPD) can influence the developmental trajectory. The presence of mood symptoms may complicate the diagnosis of adult ADHD. On the other hand, psychiatric comorbidity may disguise ADHD clinical picture making it difficult to have an appropriate diagnosis. A failure to distinguish or correctly identify the coexistence of BD, BPD, and ADHD can result in treatment and therapeutic mistakes; it can also be one of the reasons for the underachievement of therapeutic and outcome targets in several patients.
Aims of the study: The main purpose is to examine clinical differences and similarities in mood symptoms, illness course, temperamental and clinical associated features in a BD sample grouped on the basis of the presence/absence of ADHD diagnosis and BPD features. The secondary objective is the identification of clinical features useful to differentiate ADHD from BPD patients.
Material and Methods: 374 patients meeting the DSM-IV criteria for BD were consecutively recruited in the inpatient and outpatient settings of the Psychiatry Unit (UO 1) of Azienda Ospedaliero-Universitaria of Pisa over a period of about 1 year. The sample includes 184 female (48.1%) and 194 male subjects (51.9%). All the patients were evaluated with the SCID I for the assessment of Axis I psychiatric disorders and the BPD module of SCID II. Data regarding the diagnosis of BD were recorded by means of SIMD, semi-structured interview allowing the systematic collection of information regarding the current episode, the course and family history. ADHD has been confirmed with the DIVA 2.0, a semi-structured interview for the diagnosis of ADHD according to DSM-IV, whereas BPD diagnosis was confirmed throughout the DIB. The functioning and the severity of the illness were evaluated with GAF and CGI scales respectively.
Statistical analyses: For comparison between groups, we used chi-square test for categorical variables and Student’s t-test for continuous variables, using p< .05. Two stepwise forward logistic regression models were then used to identify DSM-IV BPD criteria and BD clinical variables predicting the diagnosis of ADHD with p<.05 .
Results: The study population included 374 patients suffering for BD (BD-I 52.7%, BD-II 47.3%); 180 were females (48.1%) and 194 males (51.9%), with a mean age of 45.57 years (SD 15.06, range 18-79). Comorbid ADHD and BPD rated 7.8% and 19.5% respectively. The three-group comparison showed that female gender was prominent in the BPD group. ADHD and BPD patients were younger, more frequently never married or divorced and unemployed comparing to BD patients. With respect to the clinical features of BD, BD-II was more frequent in BPD patients, which presented a clinical profile similar to ADHD, clearly differentiated from BD patients as shown by the earlier age at onset of BD, high rates of comorbid Cyclothymic Disorder, similar rates of rapid cycling, similar rates in the mean number of previous depressive, manic and mixed episodes, comparable severity and functional impairment. ADHD and BPD also showed similar comorbidity pattern with alcohol and substance abuse disorders as well as similar temperamental profiles: indeed all the affective temperaments reached mean scores higher than BD patients.
Some differences in the clinical profiles emerged: BPD presented higher mean number of previous suicide attempts, more frequently atypical features and higher comorbidity rates with anxiety (namely panic and generalized anxiety disorders) and eating disorders. By the contrary ADHD reported a higher number of hypomanic episodes. Noteworthy, the 41.4% of ADHD patients met the criteria for a BPD diagnosis too. The regression analyses confirmed that the presence of more hypomanic episodes and male gender predicted the ADHD diagnosis, whereas atypical features and suicidality were associated to BPD.
Therefore, a two-group comparison was performed concerning DSM-IV BPD criteria: no differences emerged for 4 out of the 9 criteria (emotional instability, difficulty in controlling rage, transient paranoia/dissociation and with less extent impulsivity). In comparison with ADHD, BPD reported more frequently frantic efforts to avoid real or imaged abandonment, unstable and intense relationships, identity disturbance, recurrent suicidal behavior, gestures or threats and chronic feelings of emptiness. The regression analysis, involving also the gender among the independent variables, showed that ADHD diagnosis was actually not predicted only by female gender, recurrent suicidal behaviors, self-injury and chronic feelings of emptiness.
Limitations: Low number of ADHD patients. Retrospective, non-blind design, may affect the ADHD diagnosis with recall bias. Selection bias in treatment-seeking patients in a third level university center.
Discussion: In our clinical sample, BPD and ADHD patients showed few clinical differences. BPD patients were more frequently females with prevalently depressive course and showed more atypical features, higher rate of suicide attempts, and a different pattern of comorbidities with higher rates of anxiety and eating disorders. ADHD patients were more frequently males with a prevalently hypomanic course. However, most of the bipolar clinical variables considered such as BD-II subtype, very high rate of Cyclothymic Disorder, early age at onset, number of different polarity mood episodes, rapid cycling, severity of the illness and its impact on functioning, temperamental features and familial load for mood disorders resulted similar in patients with comorbid ADHD and BPD and different from other BD patients. Moreover, about half of the ADHD subsample had an adjunctive BPD diagnosis.
This overlap supports the hypothesis that ADHD and BPD might be related each other and represent distinct clinical BD phenotypes. Alternatively, a shared factor may influence the similarities in temperamental and course characteristics. In a more hypothetical vein, we submit that affective lability disposition might represent the mediating core characteristic in the complex pattern of mood, anxiety, and impulsive disorders that ADHD and BPD patients report in developmental age. Anxious-sensitive symptomatology and hostile-impulsive-addictive behavior, rather than being considered independent comorbidities, might represent features related to such affective lability diathesis, largely pinpointed by common familial traits. Some differences however can be detected in the context of this instability diathesis as BPD patients showed a prominent depressive-anxious course, whereas affective instability in ADHD may assume more a hypomanic-colored course. Anyway, in this perspective cyclothymic-type mood instability may represent a neurodevelopmental condition shared by other disorders of the same nature such as ADHD, autistic spectrum disorder, Tourette’s plus syndrome and cognitive disability.
Further prospective longitudinal study on high risk populations are necessary to better define the possible relationships among BD, ADHD and BPD and other neurodevelopmental disorders.