Hi, Thanks for consulting us. As your wife is a doctor herself she atleast should know the detailed mechanism of action of an antidepressant. Anyway it is not all true that antidepressant has no role except making drowsy. Depression occurs due to imbalance of Neurotransmitter-specifically SERTALINE & ADRENALINE(chemicals act in brain and nerve). Now, SENSIVAL 25 contains NORTRYPTYLLIN- A 2nd generation TRI CYCLIC ANTIDEPRESSANT, act primarily as serotonin-norepinephrine reuptake inhibitors (SNRIs) by blocking the serotonin transporter (SERT) and the norepinephrine transporter (NET), respectively, which results in an elevation of the synaptic concentrations of these neurotransmitters, and therefore an enhancement of neurotransmission. In this way it acts against DEPRESSION. And DRYNESS OF MOUTH is one of its side effect. Nortriptyline is FDA-approved for the treatment of major depression. Though it acts quick and fast Nortriptyline has poor long-term efficacy with a high relapse rate in individuals being treated for depression, possibly due to a toxic metabolite 10-hydroxynortriptyline, being produced. Thus it is significantly inferior to other antidepressants such as moclobemide and other older antidepressants. Hope you understand.