By definition, the ADs are stress-related phenomena in which a psychosocial stressor results in the development of maladaptive states and psychiatric symptoms. The condition is presumed to be time limited, that is, a transitory reaction; symptoms recede when the stressor is removed or a new state of adaptation is defined.
That the relationship between stress and the occurrence of a psychiatric disorder is both complex and uncertain has caused many to question the theoretical basis of AD. The linear model of stress–disease interaction, which serves as the model for AD, has been questioned as well. The linear model presupposes that direct and clearly identifiable pathological reaction may follow a stressful event, a scenario that no doubt occurs in some indi-viduals with AD but may not accurately characterize others. For example, there may be multiple stressors, insidious or chronic, as opposed to discrete events. Furthermore, relatively minor pre-cipitating events may generate a disturbance in an individual who has previously been sensitized to stress.
Several authors have criticized the stressor criterion in AD because stressors are difficult to specify and measure, and their clinical implications and impact are uncertain. Questions pertain to whether patients with AD are unusually sensitive to psycho-social events not likely to cause disturbance in others. Are there individuals who have been exposed to high levels of stress, the severity or accumulation of which would probably produce nega-tive consequences in most people?
Diverse variables and modifiers are involved in the pre-sentation of AD after exposure to a stress. Cohen (1981) argued that acute stresses are different from chronic ones in both psy-chological and physiological terms; that the meaning of the stress is affected by “modifiers” – ego strengths, support systems, prior mastery – and that one must differentiate manifest and latent meaning of the stressors (e.g., loss of a job may be a relief or a catastrophe). An objectively overwhelming stress could have little impact on one individual, whereas another individual could regard a minor one as cataclysmic. A recent minor stress super-imposed on a previous underlying (major) stress (which had no observable effect on its own) may have a significant impact, not operating independently but by its additive effect: the concatena-tion of events (Hamburg, personal communication).
Despite variable findings suggesting a correlation between the acknowledgment of stress and the assignment of an AD di-agnosis, stress is not universally related to the development of psychiatric illness, and this has implications for understanding the meaning of stressors in AD. Specific types of stressful events and individual patterns of stress response appear to be prefer-entially related to the development of psychiatric symptoms in vulnerable individuals.