This year hasn't been the easiest for investors. The three major indexes headed into bear territory. Many of even the strongest stocks suffered. And as a result, investors' portfolios suffered, too. But there's reason to be positive as we exit this year and enter a new one.

First of all, bear markets don't last forever. We don't know the timing of the next bull market -- but we know it will eventually come. Meanwhile, to end 2022 on a positive note, it's a good idea to invest in stocks that are on the rise -- or ones that are ripe for a rebound. Here are three that could add a positive spark to your portfolio.

1. Axsome Therapeutics

Axsome Therapeutics (AXSM 2.79%) has climbed a whopping 100% this year. But there's reason this supercharged biotech could gain more over time. Axsome launched its first two products this year. One -- sleep disorder drug Sunosi -- it acquired from Jazz Pharmaceuticals earlier this spring. The other, antidepressant Auvelity, it commercialized this fall.

So, we've got two revenue drivers right away. But there's even more ahead. Axsome plans on submitting its migraine treatment candidate to regulators in the third quarter of 2023. And just recently, the company reported it met its primary endpoint in a phase 3 trial of a candidate for Alzheimer's disease agitation. This could represent two additional products in the next couple of years.

But there's even more. The rest of Axsome's pipeline candidates are in phase 2 or later studies. So multiple product launches aren't too far off -- as long as everything goes well in clinical trials.

All of this means Axsome's earnings could take off as of 2023 -- and continue rising well beyond. So, yes, its shares have gained a lot this year. But if you're looking for stock to buy and hold for at least five years, you might win with Axsome.

2. Moderna

Moderna (MRNA 3.28%) brought investors big returns -- a 400% gain -- back in 2020. They bet on the biotech's development of a coronavirus vaccine. Moderna has since brought in billions of dollars in vaccine sales and profit.

Now it's heading for a new phase of growth. The company's vaccine market is shifting to an annual booster market. And instead of Moderna selling boosters to governments as it's done so far, it will be selling directly to distributors. This transition is set to happen next year. And its booster has the potential to bring in billions of dollars every year.

Moving forward, Moderna's revenue engine should expand beyond coronavirus vaccines and boosters. The company has 48 programs in development. And three -- vaccine candidates for flu, respiratory syncytial virus (RSV), and cytomegalovirus (CMV) -- are in phase 3 trials. Moderna even predicts the flu and RSV candidates could hit the market within three years.

Moderna shares are heading for a 27% loss this year. But they've rebounded over the past three months. Considering the company's long-term potential, gains likely aren't over.

3. Intuitive Surgical

Intuitive Surgical (ISRG 2.21%) is getting back on track after coronavirus disruptions. When hospitalizations peaked at various points of the pandemic, hospitals postponed surgeries. That meant fewer orders for the company's instruments and accessories -- and as hospitals focused on COVID-19, they focused less on buying new robots.

But the picture looks brighter for Intuitive these days. In the most recent quarter, it reported double-digit gains in procedures and revenue. It's also important to remember the past disruptions -- or any potential future ones -- are temporary. And they aren't linked to the quality of its product.

Market share is another reason to like Intuitive. The company holds nearly 80% of the robotic surgery market. And considering the million-dollar price tag on surgical robots, it's likely hospitals will stick with Intuitive once they've bought or leased a device.

All of this means we should be optimistic about Intuitive's long-term earnings prospects. What about the stock? The shares are trading for 57 times forward earnings estimates. That's down from more than 72 earlier this year. This looks like a deal for a company with solid market leadership and double-digit growth. So, buying this stock is a surefire way to brighten your portfolio not just right now -- but over time.