The hypothesis that ECT produces selective effects on hypothalamic–pituitary activity was investigated by determining the effect of ECT on pituitary hormone release in nine depressed patients. After ECT there were massive and rapid increases in the plasma concentrations of nicotine-and oestrogen-stimulated neurophysin (NSN and ESN), prolactin (PRL) and adrenocorticotropin (ACTH), smaller increases in plasma luteinizing hormone (LH) and cortisol, a significant decrease in plasma growth hormone (GH) concentration but no change in plasma thyrotropin (TSH). There was significant attenuation of PRL responses with repeated ECT. The hormonal responses to ECT cannot simply be attributed to stress, since a similar pattern of increases in plasma hormone concentrations did not occur in psychologically normal patients in whom plasma hormone concentrations were measured during induction of anaesthesia and abdominal incision for cholecystectomy. Analysis of these hormonal responses in terms of the knowledge available on the neurotransmitter control of pituitary hormone release suggests that some of these hormonal responses to ECT may be mediated by the activation of serotonergic neurones, while others are probadly due to direct stimulation of the neuroendocrine neurones themselves.

To determine whether high plasma cortisol concentrations are a distinctive feature of depression or whether plasma cortisol is also elevated in other forms of psychosis, cortisol concentrations were measured in 59 patients with acute functional psychoses, six non-psychotic depressed patients and 37 control subjects, all free of antidepressant and neuroleptic drugs for at least three months. Patients with schizoaffective disorder, manic type, had the highest concentrations throughout the day and those with major depressive disorder, psychotic sub-type had higher concentrations than controls in the afternoon and evening. Manic and schizophrenic patients had cortisol concentrations above controls in the afternoon only. Elevated concentrations were not related to the presence of depressed mood or to duration of stay in hospital, and a return to normal occurred irrespective of the type of treatment used. Thus raised plasma cortisol concentrations are a feature of psychotic illness, but in drug-free patients are not specific for severe depression.