Which of the following is NOT a type of antidepressant?

Neuroleptic agents, also known as antipsychotics, are primarily used to treat psychiatric conditions such as schizophrenia and bipolar disorder, rather than depression. They function by altering the effects of neurotransmitters in the brain, particularly dopamine and serotonin, which can help to manage symptoms of psychosis but do not serve the purpose of alleviating depressive symptoms in the way antidepressants do.

In contrast, selective serotonin reuptake inhibitors (SSRIs), phenothiazines, and tricyclic antidepressants are all types of antidepressants. SSRIs specifically target serotonin levels to help improve mood, while tricyclics work by affecting multiple neurotransmitters, and phenothiazines, although primarily antipsychotics, can have mood-lifting effects in certain cases and are sometimes used as adjunct therapies for depression. The question focuses on differentiating between classes of medication, with neuroleptic agents standing out as not fitting into the category of antidepressants.