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272 EFFECTS OF STRESSinsult, including the damaging effects of glucocorticoid elevations. As described,the HPA-hippocampal system also appears to potentiate the behavioral expressionof vulnerability for psychiatric symptoms. Thus, vulnerable individuals whoexperience dysregulation of, or damage to, this system may be at increased riskfor developing the clinical syndrome. The fact that these systems are hypersensitiveduring adolescence may account for the rise in prodromal symptoms that hasbeen observed in this developmental stage.Psychopharmacology, HPA Activity,and Preventive InterventionInterest in the possibility of preventing the onset of psychotic disorders has burgeonedin the past decade. To date, there is limited evidence that this may be feasible,in that antipsychotic drugs appear to delay or reduce the likelihood oftransition to psychosis in vulnerable young adults who show prodromal or schizotypalsigns (McGorry et al., 2002; McGlashan et al., 2003; Miller et al., 2003).The critical mechanisms of action responsible for such an effect are not understood.Although a reduction in dopaminergic activity figures prominently in theories aboutantipsychotic efficacy, these drugs have a myriad of other neurobiological effects,including a significant reduction in cortisol levels in adult patients (Walker &Diforio, 1997). The latter effect is of particular interest because it has potentialimplications for both neuromaturational processes and preventive mechanisms.Several studies have shown that both typical antipsychotics, such as haloperidol(Wik, 1995), and atypical antipsychotics (i.e., olanzapine or risperidone) candecrease plasma cortisol in adult schizophrenia patients (Ryan, Flanagan, Kinsella,Keeling, & Thakore, 2004). Clozapine may have similar effects (Markianos,Hatzimanolis, & Lykouras, 1999), and it can also reduce the cortisol response tod-fenfluramine challenge in schizophrenia (Curtis, Wright, Reveley, Kerwin, &Lucey, 1995). The apparent dampening effects of antipsychotics on cortisol areconsistent with dopamine antagonism. Given the evidence of more severe symptomsin patients with higher baseline and challenge-induced cortisol, it is possiblethat this effect also serves to reduce symptom severity. Moreover, cortisol reductionmay be implicated in the prophylactic effects of antipsychotic drugs.The effects of other psychotropics, especially antidepressants, on cortisol secretionhave been of particular interest because the HPA axis is assumed to play a rolein the etiology of mood disorders. In adults, some antidepressants have been shownto alter cortisol, although the direction of the effects varies (Pariante, Thomas,Lovestone, Makoff, & Kerwin, 2004). Discrepant findings can be attributed, at leastin part, to the differential effects of certain subtypes of antidepressants. For example,at least one antidepressant, citalopram, a selective serotonin reuptake inhibitor(SSRI), appears to heighten cortisol secretion in normal controls and depressed