| Antidepressants are used commonly in medical and | | | | benzodiazepines (alprazolam and clonazepam).OCD |
| psychiatric practice. As a class, antidepressants have | | | | has been shown to respond to the serotonin-selective |
| in common their ability to treat major depressive illness. | | | | tricyclic clomipramine (Anafranil) and to SSRIs at high |
| Most antidepressants are also effective in the | | | | doses (e.g., fluoxetine at 60-80mg/ day). Obsessions |
| treatment of panic disorder and other anxiety | | | | tend to be more responsive to pharmacotherapy than |
| disorders. Some antidepressants effectively treat | | | | compulsions. Symptoms of OCD respond more slowly |
| obsessive-compulsive disorder (OCD) and a variety of | | | | than symptoms of major depression. Trials of 12 |
| other conditions (see indications below).The most | | | | weeks or more are needed before a medication can |
| commonly prescribed antidepressants are listed in | | | | be ruled a failure for an OCD patient.The binging and |
| Table 12-1. Antidepressants are subdivided into groups | | | | purging behavior of bulimia has been shown to |
| based on structure or prominent functional activity: | | | | respond to SSRls, TCAs, and MAOls in several open |
| selective serotonin reuptake inhibitors (SSRls), tricyclic | | | | and controlled trials. Because SSRIs have the most |
| antidepressants (TCAs), monoamine oxidase inhibitors | | | | benign side-effect profile of these medications, they |
| (MAOls), and other antidepressant compounds with a | | | | are often the first-line psychopharmacologic |
| variety of mechanisms of action. Antidepressants are | | | | treatment.Mechanisms of ActionAntidepressants are |
| typically thought to act on either the serotonin or | | | | thought to exert their effects at particular subsets of |
| norepinephrine systems, or both. Choice of medications | | | | neuronal synapses throughout the brain. Their major |
| typically depends on diagnosis, history of response (in | | | | interaction is with the monoamine neurotransmitter |
| patient or relative), and the side-effect profile of the | | | | systems (dopamine, norepinephrine, and serotonin). |
| medication. Antidepressant effects are typically not | | | | Dopamine, norepinephrine, and serotonin are released |
| seen until 2 to 4 weeks into treatment. Side effects | | | | throughout the brain by neurons that originate in the |
| must be carefully monitored, especially for TCAs and | | | | ventral brainstem, locus ceruleus and the raphe nuclei, |
| MAOls.IndicationsTable 12-2 lists the indications for | | | | respectively. These neurotransmitters interact with |
| antidepressants. | | | | numerous receptor subtypes in the brain that are |
| The main indication for antidepressant medications is | | | | associated with the regulation of global state functions |
| major depressive disorder as defined by the | | | | including appetite, mood states, arousal, vigilance, |
| Diagnostic and Statistical Manual of Mental Disorders, | | | | attention, and sensory processing.SSRls act by binding |
| 4th edition (DSM-IV). Antidepressants are used in the | | | | to presynaptic serotonin reuptake proteins, thereby |
| treatment of all subtypes of depression, including | | | | inhibiting reuptake and increasing the levels of serotonin |
| depressed phase of bipolar disorder, psychotic | | | | in the synaptic cleft.TCAs act by blocking presynaptic |
| depression (in combination with an antipsychotic | | | | reuptake of both serotonin and norepinephrine. MAOls |
| medication), atypical depression, and seasonal | | | | act by inhibiting the presynaptic enzyme (monoamine |
| depression. Antidepressants also are indicated for the | | | | oxidase) that catabolizes norepinephrine, dopamine, |
| prevention of recurrent depressive | | | | and serotonin, thereby increasing the levels of these |
| episodes.Antidepressant medications may be effective | | | | neurotransmitters presynaptically.These immediate |
| in the treatment of patients with dysthymic disorder, | | | | mechanisms of action are not sufficient to explain the |
| especially when there are clear neurovegetative signs | | | | delayed antidepressant effects (typically 2 to 4 |
| or a history of response to antidepressants.Panic | | | | weeks). Other unknown mechanisms must play a role |
| disorder with or without agoraphobia has been shown | | | | in the successful psychopharmacologic treatment of |
| to respond to SSRls, MAOls, TCAs, and high-potency | | | | depression. |