Depression definitions

Nierenberg AA, Amsterdam JD Resistant depression definition and treatment approaches. J Chn Psychiatry 51 (suppl) 39-47, 1990 Nierenberg AA, Adler LA, Peselow E, et al Trazodone for antidepressant-associated insomnia. Am J Psychiatry 151 1069-1072, 1994a Nierenberg AA, Feighner JP, Rudolph R, et al Venlafaxine for treatment-resistant unipolar depression. J Chn Psychopharmacol 14 419-423, 1994b... 

Prange AJ, Mason GA, Garbutt JC Thyroid axis syndromes in depression definitions and interpretations, in Pharmacotherapy of Depression Applications for the Outpatient Practitioner. Edited by Amsterdam JD. New York, Marcel Dekker, 1990,... 

The product of force F and the rolling radius (R) of the tires on the drive wheels is the wheel torque (T). Power depends on both torque and rotational speed (N). By definition, power is given by P = 2tiNFR = 27tNT. Wlien driving at constant speed, the driver adjusts the accelerator pedal so the drive-wheel power exactly matches the power required (P,) to overcome the resistance of the vehicle (discussed later in this article). To accelerate the vehicle, the driver further depresses the accelerator pedal so that the power available at the drit c wheels (PJ exceeds P,.. 

The anxiety disorders are a case in point. They comprise a range of conditions contiguous with the affective disorders and the stress responses (Table 4.1). Much overlap and comorbidity exist. Furthermore, definitions and diagnostic criteria have changed substantially over the years. For example, generalized anxiety disorder is a rare condition in its pure form, but a common condition if comorbid phobic and depressive disorders are accepted. 

Lifetime prevalence rates of psychiatric comorbidity co-existing with bipolar disorder are 42% to 50%.16 Comorbidities, especially substance abuse, make it difficult to establish a definitive diagnosis and complicate treatment. Comorbidities also place the patient at risk for a poorer outcome, high rates of suicidal-ity, and onset of depression.2 Psychiatric comorbidities include ... 

When our most recent - and most definitive - meta-analysis was published, the headlines in many newspapers blazoned that antidepressants don t work .1 The Daily Telegraph headline phrased it more specifically, clarifying that antidepressants are no better than dummy pills ,2 but even this headline was not entirely accurate. What our analyses actually showed was that antidepressants work statistically better than placebos, but that this statistical difference was not clinically meaningful. It was too small a difference to be of much importance in the life of a severely depressed person. 

Approximately 30-40% of patients will not respond to a given antidepressant and 60-75% may fail to achieve complete remission [16]. Consequently, in its least restricted definition, treatment resistance could be detected in the majority of depressed patients under treatment. Moreover, prior treatment failure negatively influences the response to subsequent antidepressant treatment, decreasing the odds of treatment response by a factor of 15-20% for each failed treatment [17]. The delayed onset of symptom relief (which takes three to eight weeks to occur) and the presence of adverse drug reactions contribute significantly to low treatment compliance. 

It also seems likely that some mental disorders (perhaps major depressive disorder) in their present form will fail to show evidence of taxonicity, but definitional refinement would help elucidate underlying taxa (e.g., melancholia). Thus, taxometrics may be able to serve as an impetus and a guide for revising the diagnostic system. Of course, taxometric methods alone are not sufficient to tackle this task and should be used in conjunction with dimensional methods, such as exploratory factor analysis. Dimensions provide the building blocks for construction of taxa, and research on the structure of psychopathology should integrate dimensional and taxometric methods. 

Depue, R. A., Monroe, S. M. (1978). Learned helplessness in the perspective of the depressed disorders Conceptual and definitional issues. Journal of Abnormal Psychobgy, 87, 3-20. 

Some of the depressant behavioral effects of hallucinogens may involve inhibitory postsynaptic 5-HT receptors. For example, depressant effects of hallucinogens on startle and locomotor activity may result from activation of these receptors, since 5-HT itself has similar effects. Studies on supersensitivity are lacking, however, and, again, the absence of selective antagonists prevents definitive conclusions. 

---