Nearly two-thirds of Americans own smartphones and 46 percent of those people say they “couldn’t live without” their smartphone. While smartphones can make life easier and more convenient, there are some downsides to consider.

Dr. Erica Herman of Novant Health Psychiatric Medicine in the Winston-Salem, North Carolina, area explained how smartphones can negatively impact your health.

1. Depression.

“The two major things I think about with smartphones are irregular sleep and isolation, and those two things are big components of depression,” Herman said.

Herman noted if people a lot of time on their smartphone at night, it can disrupt their sleep. And depression can stem from not getting enough sleep at the right time.

A study from the University of Pittsburgh showed that on average young adults use social media 61 minutes per day and visit social media accounts 30 times per week. More than 57 percent of the participants had moderate or high levels of sleep disturbance.

The National Sleep Foundation says the blue light emitted by screens on cell phones suppresses the production of melatonin, the hormone that controls your sleep/wake cycle. Reducing melatonin makes it harder to fall and stay asleep. Sleeping with a phone near your bed can also disturb your sleep with the chance of receiving texts, emails or calls.

Constantly spending time on a smartphone can also lead to isolation. In fact, one study estimates that people can spend up to five hours a day using their smartphone.

“We, as humans, have a need to be in community,” Herman said. “If all of our relationships are virtual, we aren’t getting the human-to-human contact we need. We have so much communication around us and we use it to ignore what’s really going on in our environment.”

2. Dulled memory.

Herman said always having access to the internet can dull your memory. Instead of memorizing, people can just look up the information they need on their phone.

3. Weight gain.

“There are two components of weight gain,” Herman said. “On one side, the phone serves as a distraction to avoid exercise. But on the other side, it plays into mindfulness. If you are completely engaging in your smartphone instead of paying attention to what you’re eating, you aren’t aware of how much food you’re consuming.”

Herman also said that while fitness apps are great, if people are too into using their phone the entire time they’re working out, they aren’t actually engaging deeply in the workout.

4. Spread of germs.

There are more germs on your smartphone than you think. A study commissioned by the Wall Street Journal showed that cell phones can pick up germs from all sorts of places. In fact, it has been shown that cell phones can have upward of 30,000 bacteria colonies growing on them. Those bacteria can cause skin breakouts and illnesses.

5. Strained neck and lower back.

Looking down at a smartphone for hours a day can also lead to neck and upper back pain, more commonly referred to as “text neck.” A recent study reported than people spend an average of two to four hours a day with their heads tilted over reading or texting on their smartphones. This position can lead to poor posture and wear and tear on the neck and upper back.

“In general, there are a lot of great things that smartphones bring to our lives,” Herman said. “But as with anything, it should be used in moderation and should be helping your life instead of being your life.”