Your reasoning is correct. Depression is an umbrella term, which covers a range of disorders with different neurocognitive aetiologies. This is the reason why p

Your reasoning is correct. Depression is an umbrella term, which covers a range of disorders with different neurocognitive aetiologies. This is the reason why patients will respond to pharmacological interventions with distinct mechanisms of action, and not to others: dopaminergic stimulants, monoamine oxidase inhibitors, glutamate receptor antagonism, catecholamine reuptake inhibition, secretion of neurotrophic factors in a particular brain region, etc. – while other patients suffer still from refractory "depression".