UNIPOLAR DEPRESSIVE DISORDERS: CLINICAL FEATURES

Patients who suffer from unipolar depressive disorders typically have a constellation of psychological, behavioral, and physical symptoms. Tables 29-1 through 29-3 list some of the most common psychological and cognitive (Table 29-1), behavioral (Table 29-2), and physical and somatic (Table 29-3) symptoms reported by patients with major depressive disorder (MDD).

Table 29-1 Unipolar Depressive Disorders: Common Psychological and Cognitive Symptoms

Depressed mood Lack of interest/motivation Inability to enjoy things Lack of pleasure/anhedonia Apathy Irritability Anxiety/nervousness Excessive worrying Reduced concentration/attention Memory difficulties Indecisiveness Reduced libido Hypersensitivity to rejection/criticism Reward dependency Perfectionism Obsessiveness Ruminations Excessive guilt Pessimism Hopelessness Feelings of helplessness Cognitive distortions (e.g., “I am unlovable”) Preoccupation with oneself Hypochondriacal concerns Low/reduced self-esteem Feelings of worthlessness Thoughts of death or suicide Thoughts of hurting other people

Table 29-2 Unipolar Depressive Disorders: Common Behavioral Symptoms

Crying spells Interpersonal friction/confrontation Anger attacks/outbursts Avoidance of anxiety-provoking situations Social withdrawal Avoidance of emotional and sexual intimacy Reduced leisure-time activities Development of rituals or compulsions Compulsive eating Compulsive use of the Internet/video games Workaholic behaviors Substance use/abuse Intensification of personality traits/pathological behaviors Excessive reliance/dependence on others Excessive self-sacrifice/victimization Reduced productivity Self-cutting/mutilation Suicide attempts/gestures Violent/assaultive behaviors

Table 29-3 Unipolar Depressive Disorders: Common Physical and Somatic Symptoms

Fatigue Leaden feelings in arms or legs Difficulty falling asleep (early insomnia) Difficulty staying asleep (middle insomnia) Waking up early in the morning (late insomnia) Sleeping too much/hypersomnia Frequent naps Decreased appetite Weight loss Increased appetite Weight gain Sexual arousal difficulties Erectile dysfunction Delayed orgasm/inability to achieve orgasm Pains and aches Back pain Musculoskeletal complaints Chest pain Headaches Muscle tension Gastrointestinal upset Heart palpitations Burning or tingling sensations Paresthesias

However, the traditional diagnostic approach to depressive disorders has identified depressed mood and loss of interest/pleasure in most activities as key features of these conditions. Both can be present at the same time, but one of them is sufficient to define depressive disorders, if certain associated symptoms are present. The cluster of associated symptoms, the duration of the syndrome, and the degree of functional impairment are essential to distinguish depressive disorders from physiological mood variability. The continuum of depression from mild, short-lasting syndromes toward severe, chronic/recurrent and disabling disorders has been repeatedly stressed.^1,2 The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV)³ defines MDD as depressive mood (irritable mood in children and adolescents), accompanied by at least physical, somatic, psychological, cognitive, and behavioral symptoms, lasting for at least 2 weeks. The accompanying symptoms (captured in the mnemonic SIG: E CAPS, a prescription for energy capsules) include insomnia or hypersomnia (S), reduced interest or pleasure (I), excessive guilt/feelings of worthlessness (G), reduced energy or fatigue (E), diminished ability to concentrate or make decisions (C), loss or increase of either appetite or weight (A), psychomotor agitation or retardation (P), and thoughts of suicide or death/suicidal behavior (S). In order to meet criteria for MDD, patients must report either depressed mood (it can be irritable mood in children and adolescents) or reduced interest/pleasure or both, as these are considered “core” symptoms of MDD, and they must report four or more of the other symptoms (depressed mood and SIG: E CAPS symptoms) (Table 29-4).

Table 29-4 DSM-IV Diagnostic Criteria for Major Depressive Episode

Presence of at least one core symptom and at least five of the following symptoms:

• Depressed mood (core symptom—can be irritable mood in children or adolescents) • Sleep disturbances (insomnia or hypersomnia—S) • Interest/pleasure in activities diminished (core symptom—I) • Guilt/feelings of worthlessness (G) • Energy decreased/fatigue (E) • Concentration diminished or indecisiveness (C) • Appetite or weight disturbed (increased or decreased) (A) • Psychomotor agitation or retardation (P) • Suicidal thoughts or thoughts of death or dying (S)

These symptoms cannot meet mixed-episode criteria, and must be cause for significant impairment in daily functioning. Symptoms cannot be direct effects of a substance or medical condition, or be better attributed to bereavement.

The DSM-IV classification of MDD has traditionally had a greater focus on the psychological symptoms of depression (such as depressed mood, lack of interest, excessive guilt, suicidal thoughts, feelings of worthlessness, and indecisiveness). Although some of the physical/somatic symptoms of MDD (primarily fatigue and both sleep and appetite disturbances) are included in the DSM-IV classification of this disorder, it is apparent that physical symptoms are underrepresented in the current nosology, despite the fact that they represent the chief complaint for a substantial proportion of patients who suffer from MDD. In fact, somatic symptoms are highly prevalent in MDD and are associated with significant disability and health care utilization. One could argue that the current, DSM-IV–based conceptualization of MDD that emphasizes psychological symptoms as key features of the disorder has led to a bias toward the underestimation of the rate of MDD in populations that primarily complain of somatic symptoms.

When this syndrome persists for at least 2 years it is called chronic depression. On the other hand, when depressed mood or lack of interest/pleasure are associated with only a few of the previously mentioned symptoms (not exceeding three), that mild syndrome lasting at least 2 weeks is called minor depression, or depressive disorder not otherwise specified (NOS). The persistence of this syndrome for at least 2 years is called dysthymic disorder (Table 29-5).³ In dysthymic disorder, the presence of a chronically (or at least intermittently) depressed mood for at least 2 years is heterogeneous clinically and etiologically, although it is clearly related to MDD. More than 70% of the patients with dysthymic disorder go on to develop MDD and to have recurrent major depressive episodes that are superimposed on the dysthymic disorder (i.e., double depression). As in the case of MDD, the majority of dysthymic patients have co-morbid medical or psychiatric disorders. Although milder than MDD, dysthymic disorder may have profound consequences on quality of life and for effective function in multiple life roles; this degree of morbidity is more reflective of the duration of dysthymic disorder than is the number of symptoms experienced.

Table 29-5 DSM-IV Diagnostic Symptom Criteria for Dysthymic Disorder

Presence of depressed mood (can be irritable mood in children/adolescents for longer than 1 year), for more days than not, for at least 2 years

Presence of at least two of the following:

• Poor appetite or overeating • Insomnia or hypersomnia • Low energy or fatigue • Low self-esteem • Poor concentration or difficulty making decisions • Feelings of hopelessness

These symptoms cannot be better accounted for by chronic major depressive disorder, or major depressive disorder, in partial remission. There cannot be a history of a prior manic episode, a mixed episode, or a hypomanic episode. This disturbance does not occur exclusively during a chronic psychotic disorder. Symptoms cause significant impairment in daily function and are not direct effects of a substance or medical condition.

DSM-IV SUBTYPES OF MDD

MDD is a fairly heterogeneous clinical entity, and the DSM-IV classification has attempted to capture these clinically variable presentations by providing specifiers that allow clinicians and clinical researchers to subtype it.