The differences between patients and normal comparison subjects that have stood up best have been due to challenge studies, eg, lactate infusion, sedation threshold, CO2 inhalation. Many psychopathologies may be due to adaptive deficiencies in cybernetic control mechanisms, best revealed by perturbing the system rather than simply observing Inhibitors,research,lifescience,medical it at rest. Combining challenges with genetic studies may prove a useful strategy in dealing with the multiple phenocopy problem. Congenital central hypoventilation syndrome The discovery that children with congenital central hypoventilation

syndrome (CCHS),who die from sleep apnea unless artificially ventilated, lack respiratory or affective response to C02 inhalation, makes it clear that. the suffocation alarm system actually exists. I speculate that the benefits of serotonergic antidepressants are due to downregulation of this hypersensitive system. That children with CCHS, who have hardly any suffocation alarm system at. all, should have their breathing inhibited by imipramine Inhibitors,research,lifescience,medical counterintuitively Inhibitors,research,lifescience,medical verifies that theory. Further, that these mortally endangered children, protected by anxious parents and fallible technology, should not. be anxious, directly contradicts modeling and conditioning theories of anxiety. CCHS is rather like PD inside out. Other findings support, this theory, in particular, the frequency of PD in respiratory

disease. Other findings suggest heterogeneity of the panic syndrome. In particular, the relationship to gastrointestinal disease, vestibular disorder, and premenstrual syndrome indicates that substantial extensions are in order. The marked parallelism between Freudian and learning theory is due to their common emphasis on contiguity Inhibitors,research,lifescience,medical conditioning, which leads to anxiety as a signal of anticipated traumatic states.

Neither theory distinguishes between panic attacks and chronic anticipatory anxiety, therefore, neither is consonant with the specific benefit of antidepressants on PDs. Separation anxiety Patients with agoraphobia often show clinging, dependent behavior and intolerance of being alone. The histories Inhibitors,research,lifescience,medical of severely impaired agoraphobic inpatients indicated that 50% recalled first distinct separation anxiety disorder. Moreover, initial panic episodes were often preceded by significant, personal losses, which perhaps indicated that some special early predilection for separation anxiety might, be later manifested as agoraphobia. The initial Freudian theory of separation was not much help because it. was simply another form of contiguity conditioning. Separation anxiety required recognition of the mother as a distinct object, the discrimination of her P450 inhibitor chemical structure presence versus her absence, and the association of states of mounting tension with her absence. Freudian theory offered no basis for postulating a distinctive drug effect on separation anxiety any more than on any other anxiety.