9 Unexpected Signs Someone May Be Struggling With Substance Use

9 Unexpected Signs Someone May Be Struggling With Substance Use

Key Takeaways 

  • #1: A substance use disorder can develop in someone who still looks successful and put together, and outward performance is not a reliable way to rule it out.
  • #2: Many of the clearest signs are behavioral, not dramatic: defensiveness over small questions, quietly giving up old activities, or being around people without really connecting with them.
  • #3: None of the signs on this list confirm a diagnosis on their own. They’re a reason to pay closer attention or start a conversation, not to jump to conclusions.
  • #4: You don’t need proof before reaching out. Care ranges from outpatient support to inpatient residential treatment, and an assessment can help identify what fits. If someone you love is in crisis, call or text 988.

 

Your brother-in-law just got promoted. Your daughter still shows up to every family dinner. Your best friend answers every text within the hour. And yet something feels different, and you can’t quite name it. Substance use disorder rarely announces itself the way most people expect. It often hides behind normal routines and good performance, which is why the signs that matter most are the ones nobody thinks to look for. 

This list covers nine signs of substance use disorder that tend to get missed because they don’t match the picture most people carry around in their heads. It’s written for the people who usually notice something first: partners, parents, adult children, and close friends who have a feeling before they have proof. At Lakeside-Milam, our team hears from family members regularly who sensed something long before they had a name for it. In King County, fentanyl and methamphetamine are behind most of the drug-related overdose deaths public health officials track each year. None of the nine signs below confirm a diagnosis on their own, but each is a starting point for paying closer attention.

 

  1. They Could Have a Substance Use Disorder, Even If Things Appear to Be Normal
  2. They Need More to Feel Normal
  3. Small Questions Turn Into Big Arguments
  4. They’ve Quietly Stopped Doing Things They Used to Love
  5. Money Doesn’t Add Up the Way It Used To
  6. Sleep and Energy Are Out of Sync With Their Life
  7. They Keep Choosing Substances Over Things That Used to Matter
  8. Restlessness Shows Up Where Requests Used To
  9. They’re Around People Constantly, But Not Really With Them

They Could Have a Substance Use Disorder, Even If Things Appear to Be Normal.

A substance use disorder can exist right alongside a person who looks, by every outward measure, like their life is perfectly normal: going to work, showing up to family events, keeping the household running. In fact, someone can meet the clinical criteria for a substance use disorder while continuing to function at work, at home, and in relationships, sometimes for years before anything visibly slips. 

This is part of what the disease model of addiction, the framework behind how Lakeside-Milam approaches treatment, tries to explain: substance use disorder is a chronic, treatable condition, not a character flaw, and it can develop underneath a life that still looks put together on the surface. 

If something feels off even though everything on the surface looks normal, that instinct is worth trusting. Looking fine and being fine are not the same thing. 

They Need More to Feel Normal

Tolerance, needing markedly more of a substance to get the same effect, is one of the clearest markers used to identify a substance use disorder. 

In practice, this can look like someone who used to have a drink or two at a gathering now finishing most of what’s in front of them, or someone who needed one prescription pill for pain now needing several just to feel steady enough to get through an ordinary day. 

Pay attention to the amount, not just the presence, of use. A pattern of needing more to reach the same baseline matters on its own, even before anything else looks unusual. 

Small Questions Turn Into Big Arguments

A sudden defensiveness over ordinary questions, what time they got home, why a receipt looks different, who they were with, can be a sign that someone is protecting something they don’t want looked at closely. Sudden mood changes and irritability are among the behavioral signs worth watching for. 

This often shows up as a short fuse over questions that used to get a simple answer. A quick “why does it matter” or a flat refusal to engage can replace what used to be an easy exchange. 

If a normal question now reliably triggers an outsized reaction, that shift in itself is informative, regardless of what the answer eventually turns out to be. 

They’ve Quietly Stopped Doing Things They Used to Love

Giving up activities that used to matter, a hobby, a sport, a standing commitment with friends, is one of the patterns clinicians look for when they assess a substance use disorder. 

Often it doesn’t look dramatic. Someone stops signing up for the softball league, stops going to the gym, or stops volunteering, and explains each one away separately: too busy, too tired, not feeling it lately. 

Look at the pattern rather than any single explanation. When several things someone used to care about all quietly fall away around the same stretch of time, that’s worth noticing as a group, not one at a time. 

Money Doesn’t Add Up the Way It Used To

Unexplained financial strain, missed payments, sudden requests to borrow money, or accounts that don’t reconcile, is a recognized warning sign of substance use. 

This can look like a paycheck that seems to disappear faster than it used to, new debt that doesn’t match any purchase anyone can point to, or a person who used to be careful with money suddenly asking to borrow some without a clear reason. 

If the numbers stop making sense and the explanations keep changing, treat that as its own signal, separate from whatever story accompanies it. 

Sleep and Energy Are Out of Sync With Their Life

Substance use disorder often shows up physically before it shows up anywhere else: disrupted sleep, unusual fatigue, or energy that doesn’t match the day someone actually had. 

This might look like someone who’s sleeping most of the weekend away, or the opposite, someone who seems wired well past when they should be winding down. 

A body that’s consistently out of sync with a person’s actual schedule and workload is a physical sign, not just a mood or a phase, and it’s worth paying attention to as one. 

They Keep Choosing Substances Over Things That Used to Matter

Continuing to use in ways that get in the way of responsibilities at work, at home, or in relationships, and doing it repeatedly rather than as a one-time lapse, is one of the core patterns behind a substance use disorder diagnosis. 

In everyday terms, this can look like missing a kid’s recital because “something came up,” being late to work more often than not, or being present at a family event but checked out for most of it. 

Notice when the same kind of commitment keeps losing out, not just once, but as a repeating pattern. 

Restlessness Shows Up Where Requests Used To

Craving, an intense urge to use that shows up on its own timeline rather than in response to anything happening around them, is one of the diagnostic markers in the current clinical criteria for substance use disorder. 

Family members often notice this as a kind of restlessness that doesn’t match the moment: someone who suddenly needs to step out, gets fidgety at a specific point in the evening, or seems distracted in a way that has nothing to do with the conversation happening around them. 

If restlessness reliably shows up at certain times or in certain settings, it’s worth treating as information rather than a personality quirk. 

They’re Around People Constantly, But Not Really With Them

Substance use disorder tends to push people toward isolation, even when they’re physically surrounded by others. Withdrawal from family and friends is a common warning sign, but that withdrawal doesn’t always mean fewer plans or less time together. Sometimes it means being present without really being there. 

This can look like someone who still comes to every dinner but rarely says much, or who’s around constantly but stops being honest about what’s going on in their life. 

If a relationship feels less honest or less mutual than it used to, even though the two of you still spend plenty of time together, that shift matters as much as any absence would. 

None of these nine signs are proof of anything on their own. What they have in common is that they hide inside routines that still look mostly normal: the job that’s still getting done, the person who still shows up. Substance use disorder is easier to address early than late. 

If you’re worried, you don’t need to have all the answers before you reach out. Care ranges from outpatient support to inpatient residential treatment, and an assessment can help sort out what actually fits the situation in front of you, rather than what you’re picturing. 

If someone you love is in crisis, call or text 988 for immediate support. 

At Lakeside-Milam, our team can talk through what you’re seeing and help you figure out a next step. If you have questions about what’s right for your situation, our admissions team is here to help. 

Frequently Asked Questions 

What is a substance use disorder?

A substance use disorder is a diagnosable, treatable medical condition in which a person’s use of alcohol or drugs causes ongoing problems with their health, relationships, or daily responsibilities, but they continue to use anyway. It exists on a spectrum from mild to severe, based on how many diagnostic criteria a person meets. 

What’s the difference between substance use and substance abuse?

Substance use refers to any use of alcohol or drugs, which on its own isn’t necessarily a disorder. It becomes a diagnosable disorder when that use causes real problems, at work, at home, physically, or in relationships, and continues despite those problems. Clinicians now use “substance use disorder” rather than “abuse,” in part because it focuses on the pattern and its effects rather than passing judgment on the person. 

Is addiction a disease?

Yes. Addiction, or substance use disorder, is understood as a chronic, treatable medical condition that changes how the brain manages reward, stress, and self-control. Framing it as a disease rather than a moral failing is central to how Lakeside-Milam approaches treatment. 

Can someone have a substance use disorder and still function normally?

Yes, and it’s one of the more misunderstood parts of the condition. A person can meet the clinical criteria for a substance use disorder while still performing well at work, maintaining relationships, and meeting most day-to-day obligations, sometimes for a long stretch of time. Outward functioning is not a reliable way to rule out a substance use disorder. 

What should I do if I think someone I love has a substance use disorder?

Start by paying attention to patterns rather than single incidents, and consider having a direct, non-judgmental conversation about what you’ve noticed. A licensed treatment provider can complete an assessment and help identify what level of care, if any, actually fits the situation. If the person is in crisis, call or text 988 for immediate support. 

Sources 

Reach Out to Our Recovery Experts 24/7

FREE Drug & Alcohol Evaluations.