Opium perfume for women was launched in the year 1977, and has since become a milestone in the perfume world. Its spicy notes are easily recognisable, and even if in some countries there is still a ban against it because of its name, it goes without saying that it doesn't contain any opium poppy. 

The opening notes are deeply oriental, woody and spicy, a reminder of the resinous base notes of Rive Gauche, another classic perfume by Yves Saint Laurent. There are also floral notes to remind us that after all Opium perfume is for women.
After a couple of minutes, the woody notes almost disappear, and what is left is fresh cinnamon and something between pepper, nutmeg and clove. The floral notes also gain as much intensity: the presence of ylan-ylang (like in River Gauche) is clear, along with vanilla, plus more delicate florals like rose and jasmine.
If you stop smelling for a few seconds and then get your nose close again, the spicy woody notes will again be prominent, absorbing the florals. Here and there, an note of orange zest peeps in, bringing some freshness to the spices.
In Opium perfume's heart notes the spices become sweet, more resinous than woody, making cinnamon and vanilla notes stand out. I would say there is also a sandalwood touch, but the rose and the ylang-ylang notes are more clear.

Even though Opium parfum is traditionally described as an oriental fragrance, it's actually less thick than other perfumes by Yves Saint Laurent of the same years, like Rive Gauche or YSL Paris. Woods and spices are obviously there, but relatively soft, yet strong enough for Opium fragrance to be a perfume made for the winter, when it can be used everyday even in the office.
Is it a perfume for a first date? Unfortunately, like all perfumes with attitude, it can be a double edged sword: it may attract irresistibly, or have the opposite (irresistible) effect.
The strength of Opium perfume's notes make it more suitable for a woman of 30+ years of age, up to 60, even if the version Eau de Toilette can be worn by anybody around 25.