Can depression be diagnosed for under 18 year olds?

Adolescent depression is a disorder occurring during the teenage years marked by persistent sadness, discouragement, loss of self-worth, and loss of interest in usual activities. It can be a temporary response to various situational stressors including normal maturation, hormonal changes, and independence conflicts with parents, school and social stressors, and the stress associated with them. It may also be a reaction to a disturbing event, such as the death of a friend or relative, a breakup with a boyfriend or girlfriend, or failure at school. Adolescents, who have low self-esteem, are highly self-critical, and  feel little sense of control over negative events, are particularly vulnerable to depression when they experience stressful events. True depression in teens is often difficult to diagnose because normal adolescent behavior is marked by mood swings, with alternating periods of feeling ‘the world is a great place’ and ‘life sucks.’ These moods may alternate over a period of hours or days. Persistent depressed mood, faltering school performance, failing relations with family and friends, substance abuse, and other negative behaviors may indicate a serious depressive episode. These symptoms may be easy to recognize, but depression in adolescents often manifests very differently than these classic symptoms. Excessive sleeping, change in eating habits, even criminal behavior (like shoplifting) may be signs of depression. Another common symptom of adolescent depression is an obsession with death, which may take the form either of suicidal thoughts or of fears about death and dying.

Symptoms

depressed or irritable mood

temper, agitation

loss of interest in activities, apathy

reduced pleasure in daily activities

inability to enjoy activities which used to be sources of pleasure

change in appetite, usually a loss of appetite but sometimes an increase

change in weight (unintentional weight loss or unintentional weight gain)

persistent difficulty falling asleep or staying asleep

excessive daytime sleepiness

fatigue

difficulty concentrating

difficulty making decisions

memory loss (amnesia) episodes

preoccupation with self

feelings of worthlessness, sadness, or self-hatred

excessive or inappropriate feelings of guilt

acting-out behavior (missing curfews, unusual defiance)

thoughts about suicide or obsessive fears or worries about death

plans to commit suicide or actual suicide attempt

excessively irresponsible behavior pattern

If these symptoms persist for at least two weeks and cause significant distress or difficulty functioning, treatment should be sought.

That's untrue! You can definitely be diagnosed at 17. The only implication I can think of is you may need parental permission to take meds or see a therapist.

I had my first episode when I was 13. It can happen earlier than 18, although 18 is a rough estimate of when it typically shows up in people, but you could definitely be having your first episode. CBT will probably work great for you.

Ask about going on medication. Wellbutrin is energizing and does not affect your sex life, if anything it might increase it slightly, so that is good for romance.