The relationship between depression and mania remains poorly understood and is responsible for much of the confusion about mixed states. The difficulty in conceptualizing opposite states such as euphoric and depressive moods during the same episode may account for the considerable differences in reported frequencies of mixed states, among acutely manic patients. It is possible that the fundamental mood characteristic of mania is not tonality of mood (e.g. euphoric, irritable or depressed mood), but rather the intensity of emotions.

We interviewed 30 patients hospitalized for a manic episode, asking about their symptoms during the episode, using the list of symptoms for manic and depressive episode of the DSM-IV criteria. Emotional hyper-reactivity, defined as an increase in the intensity of all emotions, was assessed using the Hardy Scale. Manic symptoms were also assessed by a clinician using the Beck–Rafaelsen Mania Scale.

This study showed that most of the manic episodes presented many dysphoric symptoms, more particularly depressive mood (33%), irritability (53%), anxiety (76%), and recurrent thoughts of death or suicidal ideation (33%). However, only 10% of our sample met the criteria for mixed state. The other symptoms reported by patients and included in the DSM-IV criteria for depressive mood are common between depressive and manic episodes. All patients (100%) reported that they felt all their emotions with an unusual intensity.

We suggest that the most appropriate way to define mood in manic states is as a function of intensity, and not as a function of tonality. This definition circumvents the arbitrary dichotomy between mania and mixed state. With this definition, manic episodes can be described as being more or less dysphoric, with the actual characteristics of dysphoria encompassing irritability, anxiety, or depressive affect. This point could be extremely helpful in discriminating mixed state or dysphoric mania from depression.

Although some evidence suggests that borderline personality disorder (BPD) is primarily a disorder of the emotion regulation system, findings remain inconsistent. One potential explanation for this is the moderating role of dissociation.

In this study, 33 female subjects with BPD and 26 healthy controls (HC; matched by education level and nicotine intake) were presented idiographic aversive, standard unpleasant and neutral scripts. Modulation of startle reflex and electrodermal responses (skin conductance level; SCL) were measured during imagery of emotional and neutral scripts. Additionally, self-reports of emotional experience (valence and arousal) and present-state dissociation were assessed.

Patients with BPD showed elevated levels of dissociative experiences during testing. Present-state dissociation mediated group differences in SCL and startle response between the HC and BPD groups.

These results suggest that careful attention must be paid to the moderating effect of dissociative symptoms on the psychophysiological responses of BPD patients. Furthermore, the findings have important implications for the assessment and treatment of BPD, including the need to carefully assess BPD patients for dissociative symptoms and to incorporate the treatment of dissociation.