Effects of dose and interdose interval on conditioned heart rate tolerance to smoking.

The effects of an environmental cue and smoking administration on heart rate (HR) responses to smoking were investigated in 2 studies. The 1st study was performed without smoking, to rule out the possibility that the cue manipulations alone could produce HR habituation. Thirty-six male nonsmokers were exposed to 6 trials of a changing or repeating cue (segments of a story on audiotape), followed by a paced-breathing period. HR habituation was not found. In the 2nd study, 40 male smokers smoked 4 puffs every 10 min (small-dose/long-interdose interval [IDI]) or 6 puffs every 5 min (large-dose/short-IDI) in 6 trials. The same repeating or changing cue preceded smoking. Only the repeating-cue, small-dose/long-IDI group developed HR tolerance. Modifying the cue on Trial 6 did not reverse tolerance. The results indicated that (a) tolerance to smoking appears to be subject to conditioning, (b) this effect depends on the dose and IDI, and (c) the observed tolerance is not likely to be a result of the effects of the cue alone. Nonassociative tolerance to smoking a high-dose/short-IDI did not occur in this study.

Anxiety and depression in patients receiving implanted cardioverter-defibrillators: a longitudinal investigation.

OBJECTIVE: The implantable cardioverter-defibrillator (ICD) has dramatically improved survival rates following sudden cardiac death episodes. However, researchers have devoted little attention to the psychosocial consequences of living with the device. The current study used a longitudinal design to evaluate the impact of adaptation to the ICD on incidence and severity of anxiety and depression. METHOD: ICD recipients were administered standardized anxiety and depression questionnaires as well as questions evaluating quality of life related to the ICD in two consecutive yearly assessments. A preliminary evaluation of potentially important theoretical variables, such as the perceived predictability and controllability of shock onset was also conducted. RESULTS: One-third of the study population (N = 38) had clinically significant levels of anxiety, depressed mood, and fear of symptoms of autonomic arousal. These negative affective states persisted over time, with 40 to 63 percent of subjects continuing to have ongoing difficulties over a one-year time period. Anxiety about the ICD firing was closely associated with the occurrence of depression, while avoidance of activities was associated with anxiety. "Worry" about the ICD and a belief that ICD firing can be predicted were associated with anxiety sensitivity. CONCLUSIONS: Depressive and anxiety states in ICD recipients may be frequent, clinically significant, and resistant to spontaneous resolution. Early signs of anxiety and depression in ICD recipients should be evaluated. Implications for future research are discussed.