Some possible adverse reactions of SSRIs include headache, gastrointestinal side effects, dry mouth, sedation or insomnia and activation. Activation refers to a state of psychomotor agitation that includes symptoms of insomnia, disinhibition and restlessness that may result in discontinuation of a medication. There is a rare risk of suicidal thoughts or behaviors with SSRIs especially when treatment is started or the dose is increased, with the rate being up to 0.7% as compared to placebo in early meta analyses of SSRIs in the treatment of adolescent depression. This led the FDA to issue a black box warning regarding this risk. Once remission is achieved, the medications are continued for at least 6 to 12 months and then there is consideration of discontinuing them. Early or premature discontinuation of medications, prior to 6 to 12 months of having achieved remission, is associated with an increased risk of relapse of the depression.The combination of psychotherapy with medications has been shown to be more effective for the treatment of depression in adolescence than medications alone.Other medications can be added to SSRIs if a partial response is achieved and further improvement is needed; these agents include lithium, bupropion and atypical antipsychotics. These options are medications that work in different ways. Bupropion (Wellbutrin) works through the neurotransmitters norepinephrine and dopamine, while mirtazapine (Remeron) affects transmission of norepinephrine and serotonin. The drugs venlafaxine (Effexor) and duloxetine (Cymbalta) work in part by simultaneously inhibiting the reuptake of serotonin and norepinephrine.
The oldest drugs on the market are not prescribed often, but may be a good option for some women. These include tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs). TCAs may cause side effects like dry mouth, constipation, or dizziness. MAOIs can cause sedation, insomnia, dizziness, and weight gain. To avoid the risk of a rapid rise in blood pressure, people taking MAOIs must also avoid eating a substance called tyramine, found in yogurt, aged cheese, pickles, beer, and red wine. Some drug side effects subside with time, while others may lessen when a drug dose is lowered. Research
Differences in the brains structure and function appear to be present in adolescents with depression though this may depend on age. Younger adolescents, mostly under the age of 18, with depression have shown greater white matter volume within frontal regions of the brain, greater cortical thickness in the anterior cingulate cortex and medial orbitofrontal cortex, as well as greater functional connectivity between cortico-limbic brain regions. Whereas older adolescents, mostly above the age of 18, appear to show lower cortical surface area in regions including the lingual, occipital gyri, as well as medial orbitofrontal and motor cortices. Results such as these have led to the hypothesis that the biological causes of depression may in part be neurodevelopmental, with its biological underpinnings forming early on in brain development.