Withdrawn. Irritable. Sleepy. This could describe almost any teenager, but these are also symptoms of teen depression.

Teen depression sometimes gets overlooked because it doesn’t always look like depression in adults. For example, sadness is a core feature of most depression and what most people associate with depression, according to Dr. Ken Duckworth, medical director of the National Alliance on Mental Illness. Many teens also experience other symptoms—parents might miss these warning signs.

1.  Sleep disturbance. “Many adolescents sleep until noon on a Saturday, but if you notice a change in their sleep or their sleep is irregular even more than before, that’s something to worry about,” Dr. Duckworth says.

2.  Social changes. “Adolescents are typically very focused on social connections,” he says. “If they’re not interested in their social network and they want to quit sports, pay attention to that.”

3.  Physical symptoms. Some teens demonstrate their emotional distress through physical symptoms, such as headaches, stomach aches, weakness, and body aches.

4. Substance abuse. Some depressed teens use drugs and alcohol to change how they’re feeling. Abusing drugs and alcohol also increases the risk for depression or worsening depression.