Halloween can be a scary time for trick-or-treaters, but if you've invested in risky stocks over the years, looking at your portfolio at any time can be frightening. While stocks can, in general, deliver great long-term returns, risky investments can lead to crippling losses.

And while buying and holding a stock for the long term can result in a sizable return for investors, that's by no means going to be the case in all situations. Investors sometimes hope that a troubled stock today will be able to turn things around and become a good buy if they hold onto it long enough. That can, however, be an incredibly risky strategy.

Three stocks that have been downright awful and terrifying buys over the past five years are Intel (INTC -2.62%), iRobot (IRBT 2.06%), and Tilray Brands (TLRY -1.17%). Here's how much these companies have fallen in value during that time and whether any one of them has a realistic chance of turning things around.

Intel: Down 54%

Investing in technology has been a good move for many investors in recent years as growing excitement surrounding artificial intelligence (AI) has led to some incredible returns. But not every stock is going to turn out like Nvidia. While Intel wants to be a big player in the AI market, it may not be an easy path for it to get there.

Intel has been investing in building its foundry business, and that's been a struggle, to say the least. The company has been incurring losses and suspended its dividend for the sake of freeing up cash to focus on its growth strategy. There is, however, reason for hope in the long run, as news that it's making custom chips for Amazon has made some investors optimistic that the company is on the right path.

By no means is Intel's business doomed, given the need for domestic chips in the U.S. However, it may not be an easy or quick turnaround for the company and its stock. Intel has the potential to be an underrated buy, but this isn't an investment for the faint of heart. Holding the company's shares in your portfolio will require patience, as it could take years for the business to get back to generating consistent profits and being a safe investment again.

iRobot: Down 84%

Roomba-maker iRobot has been having a hard time growing its business, as many companies offer similar products at cheaper prices. For consumers, spending several hundreds of dollars on a robotic vacuum may seem like an unnecessary expense these days. A look at iRobot's financials seems to suggest that the company is not only finding it difficult to stay out of the red, but its top line also has been declining in recent years.

From an annual profit of $147 million in 2020 and revenue totaling more than $1.4 billion, iRobot's financials look drastically worse of late as it incurred a loss of just under $305 million last year and revenue was down to $891 million. Things haven't been looking good, though investors were optimistic that an acquisition might save the business with Amazon looking to buy the company. When that fell through earlier this year (due to regulatory issues), the stock crashed.

I'm not optimistic that iRobot's stock can recover unless there's news of another acquisition. Given the company's poor financials and lack of growth, this is a stock investors may want to avoid right now.

Tilray Brands: Down 93%

Investing in cannabis stocks seemed like a no-brainer investment five years ago. After all, a large chunk of the U.S. population was in favor of legalization, so it would seem to follow that investing in a top cannabis producer would make for a good investment idea. The problem is that legalization still hasn't occurred in the U.S. and there's no guarantee it will anytime soon.

Optimism in the cannabis industry has faded, and once high-flying pot stocks have become among the worst investments over the past five years. Canada-based Tilray Brands is down more than 90% over that stretch.

The company expanded its operations by acquiring alcohol companies as a way to at least grow its business without being entirely dependent on waiting for the U.S. pot market to open up. While many states have legalized marijuana, Tilray's cannabis products won't be able to cross the border into the U.S. until pot becomes legal on a federal level, and many investors have given up on waiting.

Unfortunately, even with its pivot to alcohol, Tilray is an unprofitable company with operating losses that totaled more than $108 million over the past four quarters. There may be a lot of upside for the stock should the U.S. government decide to legalize marijuana, but unless you have a high risk tolerance and are willing to wait for years, you may be better off pursuing other growth stocks instead of Tilray.