Mood Disorders

Introduction

Mood disorders are generally defined according to criteria listed in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV; APA, 1994). While the DSM-IV lists 10 mood disorders, only major depressive disorder (MDD) and bipolar disorder (BD) will be addressed in this entry. MDD is defined as exhibiting either depressed mood or loss of interests or pleasure most of the day nearly every day for at least 2 weeks and accompanied by at least five of the following symptoms: (1) change in weight or appetite; (2) insomnia or hypersomnia; (3) psychomotor agitation or retardation; (4) fatigue or loss of energy; (5) feelings of worthlessness or excessive guilt; (6) poor concentration or indecisiveness; and (7) suicidal ideation or attempt. BD involves a manic episode for at least 1 week and may or may not involve the symptoms of MDD. Symptoms of a manic episode include either euphoria or irritability and at least three of the following symptoms: (1) inflated self-esteem or grandiosity; (2) decreased need for sleep; (3) talkativeness or pressured speech; (4) flight of ideas; (5) distractibility; (6) increase in activity level; and (7) excessive involvement in pleasurable yet risky activities.

This entry will first address difficulties in assessing MDD and BD. Second, several assessment devices will be described. Third, the need for additional devices will be noted. Finally, it will be concluded that assessment devices for MDD and BD should be multivariate and include not only symptoms of disordered mood but also causal and maintenance factors that can guide prevention and treatment strategies.

Definitional Challenges to Assessment of Mood Disorders

DSM-IV criteria for MDD and BD are quite heterogeneous and some are ill-defined. For MDD, either depressed mood or anhedonia must be present most of the time, but what constitutes ‘most’ is not specified. Furthermore, it is unclear how these two criteria are measured separately. Is it possible to exhibit dysphoria but still exhibit pleasure? Another measurement challenge is that the DSM-IV weighs all seven symptoms of MDD equally. If a person is very sad and suicidal but has normal appetite, sleep pattern, and energy level, is this person not disordered? In clinical settings, suicidal people are given emergency treatment but, as discussed below, assessment devices for MDD would not alert the clinician of a serious problem. Therefore, another measurement challenge is how to weigh the significance of each of the seven symptoms that accompany dysphoria or anhedonia.

For BD, the defining symptom to assess is either euphoria or irritability. Excessive happiness and excessive anger are different emotional states that involve different cognitions and behaviours. It is unclear why they are not recognized as separate mood disorders. There are few assessment devices for BD and this definitional confusion may be one reason this disorder has been difficult to measure.

Another challenge to the measurement of MDD and BD is the temporal criteria for diagnosis. Identification of symptoms lasting 2 weeks for MDD and 1 week for BD requires accurate retrospective reporting which is subject to not only memory bias but also the very symptoms of the disorders (e.g. difficulty concentrating and distractibility). While continuous observation or self-monitoring may obviate this issue, most techniques for assessment of mood disorders are based on a single administration of the device.

...