Imipramine Binding as a Predictor of Fluoxetine Response in Depressed Patients

Abstract

We evaluated platelet ³H-imipramine (³H-IMI) binding parameters (B_max and K_d) at baseline (t₀) and 2 months after (t₁) treatment with fluoxetine in a group of outpatients affected by a major depressive episode, according to DSM-IIIR criteria. The possible relationships between biological parameters and the Hamilton Rating Scale for Depression (HRSD) total score were examined. The results confirmed previous reports that depressed patients possessed a lower density (B_max) of platelet ³H-IMI binding sites than healthy controls, but the B_max tended to decrease with fluoxetine. In addition, we observed a negative correlation between B_max values at t₀ and the HRSD total scores at t₁ indicating that the patients who responded better to fluoxetine were those with a lower B_max at t₀. Future studies will substantiate this preliminary observation on the possible usefulness of platelet ³H-IMI binding as a predictor of pharmacological response.

Decreased Platelet ³H-Paroxetine Binding in Obsessive-Compulsive Patients

“…In fact patients with depression [30,31] and social phobia [32] have been reported to have a normal binding, while controversial data exist for patients with panic disorder [33,34]. This is not surprising, since OC patients respond almost exclusively to SSRIs and a re duced IMI binding has been related to a positive response to SSRIs [35,36], The specificity of the reduced -^-parox etine binding in OCD is supported by our observation of a negative correlation between symptom severity, as rated by the Y-BOCS total score, and the number of 3H-paroxetine binding sites.…”

Differential Brain Metabolic Predictors of Response to Paroxetine in Obsessive-Compulsive Disorder Versus Major Depression

“…Many methods have been employed to investigate neurobiological predictors of response to antidepressant medications in OCD and major depressive disorder, including neurotransmitter and receptor assays (3)(4)(5)(6)(7)(8), neuroendocrine challenge tests (9)(10)(11)(12)(13), neurocognitive testing (14,15), auditory evoked potentials (16), quantitative electroencephalography (17)(18)(19)(20), and pharmacogenetics (21)(22)(23). Unfortunately, few of these findings have been replicated, and none have localized specific neuroanatomical substrates for treatment response.…”

Platelet serotonin transporter in coeliac disease

“…Changes in 'H-IMI binding sites have been reported in a broad range of neuropsychiatric disorders. including depression and headache (8), so that it is generally believed that such modifications represent markers of serotonergic dysfunctions crossing different diagnostic entities and probably linked to psychopathological dimensions (14), or to a possible positive pharmacological response to selective 5-HT re-uptake inhibitors (28). The link between the 5-HT transporter and depression is however questioned by the reports of negative findings when this structure was evaluated with the binding of paroxetine (15,16).…”