Multihormonal responses to clonidine in patients with affective and psychotic symptoms

The neuroendocrine responses to the alpha(2)-adrenoreceptor agonist clonidine (CLO) (0.35 mg if body weight <65 kg or 0.375 mg if body weight> or =65 kg, PO) were studied in a large group of subjects: 134 drug-free inpatients--with either DSM-IV schizophrenia (SCZ, n=31), schizoaffective disorder (SAD, n=16), or major depressive episode (MDE, n=87) - and 22 hospitalized controls (HCs). Comparison with a previous placebo test performed in a subgroup of 92 subjects (46 MDEs, 20 SCZs, 8 SADs, and 18 HCs) showed that CLO induced a significant increase of growth hormone, prolactin (PRL) and thyrotropin (TSH) levels but no significant change in adrenocorticotropin and cortisol release. According to diagnostic categories, we found significantly lower GH stimulation in MDEs and in SADs compared to HCs or to SCZs. In addition, we found significantly lower CLO induced PRL and TSH stimulations in paranoid SCZ patients compared to controls and disorganized SCZ patients. Taken together, these results suggest a hyposensitivity of noradrenergic alpha(2)-receptors in patients with affective symptoms.